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NADPH oxidase (NOX) is a main producers of reactive oxygen species (ROS) that may contribute to the early pathogenesis of diabetic retinopathy (DR). ROS has harmful effects on endogenous neuro-survival factors brain-derived neurotrophic factor (BDNF) and sirtuin 1 (SIRT1) are necessary for the growth and survival of the retina. The role of NOX isoforms NOX4 in triggering ROS in DR is not clear. Here we determine the protective effects of a plant-derived NOX inhibitor apocynin (APO) on NOX4-induced ROS production which may contribute to the depletion of survival factors BDNF/SIRT1 or cell death in the diabetic retinas. Human retinal Muller glial cells (MGCs) were treated with hypoxia mimetic agent cobalt chloride (CoCl2) in the absence or presence of APO. Molecular analysis demonstrates that NOX4 is upregulated in CoCl2-treated MGCs and in the diabetic retinas. Increased NOX4 was accompanied by the downregulation of BDNF/SIRT1 expression or in the activation of apoptotic marker caspase-3. Whereas, APO treatment downregulates NOX4 and subsequently upregulates BDNF/SIRT1 or alleviate caspase-3 expression. Accordingly, in the diabetic retina we found a positive correlation in NOX4 vs ROS (p = 0.025; R2 = 0.488) and caspase-3 vs ROS (p = 0.04; R2 = 0.428); whereas a negative correlation in BDNF vs ROS (p = 0.009; R2 = 0.596) and SIRT1 vs ROS (p = 0.0003; R2 = 0.817) respectively. Taken together, NOX4-derived ROS could be a main contributor in downregulating BDNF/SIRT1 expression or in the activation of caspase-3. Whereas, APO treatment may minimize the deleterious effects occurring due to hyperglycemia and/or diabetic mimic hypoxic condition in early pathogenesis of DR.

PURPOSE: Inflammation, angiogenesis and fibrosis are pathological hallmarks of proliferative diabetic retinopathy (PDR). The CD146/sCD146 pathway displays proinflammatory and proangiogenic properties. We investigated the role of this pathway in the pathophysiology of PDR. METHODS: Vitreous samples from 41 PDR and 27 nondiabetic patients, epiretinal fibrovascular membranes from 18 PDR patients, rat retinas, human retinal microvascular endothelial cells (HRMECs) and human retinal Müller glial cells were studied by ELISA, Western blot analysis, immunohistochemistry and immunofluorescence microscopy analysis. Blood-retinal barrier breakdown was assessed with fluorescein isothiocyanate-conjugated dextran. RESULTS: sCD146 and VEGF levels were significantly higher in vitreous samples from PDR patients than in nondiabetic patients. In epiretinal membranes, immunohistochemical analysis revealed CD146 expression in leukocytes, vascular endothelial cells and myofibroblasts. Significant positive correlations were detected between numbers of blood vessels expressing CD31, reflecting angiogenic activity of PDR, and numbers of blood vessels and stromal cells expressing CD146. Western blot analysis showed significant increase of CD146 in diabetic rat retinas. sCD146 induced upregulation of phospho-ERK1/2, NF-κB , VEGF and MMP-9 in Müller cells. The hypoxia mimetic agent cobalt chloride, VEGF and TNF-α induced upregulation of sCD146 in HRMECs. The MMP inhibitor ONO-4817 attenuated TNF-α-induced upregulation of sCD146 in HRMECs. Intravitreal administration of sCD146 in normal rats significantly increased retinal vascular permeability and induced significant upregulation of phospho-ERK1/2, intercellular adhesion molecule-1 and VEGF in the retina. sCD146 induced migration of HRMECs. CONCLUSIONS: These results suggest that the CD146/sCD146 pathway is involved in the initiation and progression of PDR. ispartof: INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE vol:62 issue:9 ispartof: location:United States status: published

PURPOSE: To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR). METHODS: Vitreous samples from 29 PDR and 19 nondiabetic patients, epiretinal fibrovascular membranes from 15 patients with PDR and Müller cells were studied by enzyme-linked immunosorbent assay, immunohistochemistry and Western blot analysis. RESULTS: We showed a significant increase in expression of IL-11, soluble(s) IL-11Rα, sCD163 and VEGF in vitreous samples from PDR patients compared to nondiabetic controls. Significant positive correlations were found between levels of VEGF and levels of IL-11 and sCD163. Significant positive correlations were found between microvessel density and number of blood vessels and stromal cells expressing IL-11, IL-11Rα and CD163 in PDR epiretinal membranes. The hypoxia mimetic agent cobalt chloride induced upregulation of IL-11 and IL-11Ra in cultured Müller cells. CONCLUSIONS: IL-11/IL-11Rα signaling and CD163+ M2 macrophages might be involved in PDR angiogenesis. ispartof: OCULAR IMMUNOLOGY AND INFLAMMATION vol:28 issue:4 pages:575-588 ispartof: location:England status: published

The transmembrane chemokine pathways CXCL16/CXCR6 and CX3CL1/CX3CR1 are strongly implicated in inflammation and angiogenesis. We investigated the involvement of these chemokine pathways and their processing metalloproteinases ADAM10 and ADAM17 in the pathophysiology of proliferative diabetic retinopathy (PDR). Vitreous samples from 32 PDR and 24 non-diabetic patients, epiretinal membranes from 18 patients with PDR, rat retinas, human retinal Müller glial cells and human retinal microvascular endothelial cells (HRMECs) were studied by enzyme-linked immunosorbent assay, immunohistochemistry and Western blot analysis. In vitro angiogenesis assays were performed and the adherence of leukocytes to CXCL16-stimulated HRMECs was assessed. CXCL16, CX3CL1, ADAM10, ADAM17 and vascular endothelial growth factor (VEGF) levels were significantly increased in vitreous samples from PDR patients. The levels of CXCL16 were 417-fold higher than those of CX3CL1 in PDR vitreous samples. Significant positive correlations were found between the levels of VEGF and the levels of CXCL16, CX3CL1, ADAM10 and ADAM17. Significant positive correlations were detected between the numbers of blood vessels expressing CD31, reflecting the angiogenic activity of PDR epiretinal membranes, and the numbers of blood vessels and stromal cells expressing CXCL16, CXCR6, ADAM10 and ADAM17. CXCL16 induced upregulation of phospho-ERK1/2, p65 subunit of NF-κB and VEGF in cultured Müller cells and tumor necrosis factor-α induced upregulation of soluble CXCL16 and ADAM17 in Müller cells. Treatment of HRMECs with CXCL16 resulted in increased expression of intercellular adhesion molecule-1 (ICAM-1) and increased leukocyte adhesion to HRMECs. CXCL16 induced HRMEC proliferation, formation of sprouts from HRMEC spheroids and phosphorylation of ERK1/2. Intravitreal administration of CXCL16 in normal rats induced significant upregulation of the p65 subunit of NF-κB, VEGF and ICAM-1 in the retina. Our findings suggest that the chemokine axis CXCL16/CXCR6 and the processing metalloproteinases ADAM10 and ADAM17 might serve a role in the initiation and progression of PDR. ispartof: FRONTIERS IN IMMUNOLOGY vol:11 ispartof: location:Switzerland status: published

The macrophage migration inhibitory factor (MIF)/CD74 signaling pathway is strongly implicated in inflammation and angiogenesis. We investigated the expression of MIF and its receptor CD74 in proliferative diabetic retinopathy (PDR) to reveal a possible role of this pathway in the pathogenesis of PDR. Levels of MIF, soluble (s)CD74, soluble intercellular adhesion molecule-1 (sICAM-1) and vascular endothelial growth factor (VEGF) were significantly increased in the vitreous from patients with PDR compared to nondiabetic control samples. We detected significant positive correlations between the levels of MIF and the levels of sICAM-1 (r = 0.43; p = 0.001) and VEGF (r = 0.7; p < 0.001). Through immunohistochemical analysis of PDR epiretinal membranes, significant positive correlations were also found between microvessel density (CD31 expression) and the numbers of blood vessels expressing MIF (r = 0.56; p = 0.045) and stromal cells expressing MIF (r = 0.79; p = 0.001) and CD74 (r = 0.59; p = 0.045). Similar to VEGF, MIF was induced in Müller cells cultured under hypoxic conditions and MIF induced phosphorylation of ERK1/2 and VEGF production in Müller cells. Intravitreal administration of MIF in normal rats induced increased retinal vascular permeability and significant upregulation of phospho-ERK1/2, NF-κB, ICAM-1 and vascular cell adhesion molecule-1 expression in the retina. MIF induced migration and proliferation of human retinal microvascular endothelial cells. These results suggest that MIF/CD74 signaling is involved in PDR angiogenesis. ispartof: FRONTIERS IN IMMUNOLOGY vol:10 ispartof: location:Switzerland status: published

PURPOSE Galectin-1 regulates endothelial cell function and promotes angiogenesis. We investigated the hypothesis that galectin-1 may be involved in the pathogenesis of proliferative diabetic retinopathy (PDR). METHODS Vitreous samples from 36 PDR and 20 nondiabetic patients, epiretinal fibrovascular membranes from 13 patients with PDR, rat retinas and human retinal Muller glial cells were studied by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry and Western blot analysis. In vitro angiogenesis assays were performed and the adherence of leukocytes to galectin-1-stimulated human retinal microvascular endothelial cells (HRMECs) was assessed. RESULTS The ELISA analysis revealed that galectin-1 and vascular endothelial growth factor (VEGF) levels were significantly higher in vitreous samples from PDR patients than in those from nondiabetics (p

Background— The fibronectin-splicing variant containing extra domain A (Fn-EDA) is present in negligible amounts in the plasma of healthy humans but markedly elevated in patients with comorbid conditions, including diabetes mellitus and hypercholesterolemia, which are risk factors for stroke. It remains unknown, however, whether Fn-EDA worsens stroke outcomes in such conditions. We determined the role of Fn-EDA in stroke outcome in a model of hypercholesterolemia, the apolipoprotein E–deficient (Apoe −/− ) mouse. Methods and Results— In a transient cerebral ischemia/reperfusion injury model, Apoe −/− mice expressing fibronectin deficient in EDA (Fn-EDA −/− Apoe −/− mice) exhibited smaller infarcts and improved neurological outcomes at days 1 and 8 ( P −/− mice). Concomitantly, intracerebral thrombosis [assessed by fibrin(ogen) deposition] and postischemic inflammation (phospho–nuclear factor-κB p65, phospho–IκB kinase α/β, interleukin 1β, and tumor necrosis factor-α) within lesions of Fn-EDA −/− Apoe −/− mice were markedly decreased ( P −/− mice). In an FeCl 3 injury–induced carotid artery thrombosis model, thrombus growth rate and the time to occlusion were prolonged in Fn-EDA −/− Apoe −/− mice ( P −/− mice). Genetic ablation of TLR4 improved stroke outcome in Apoe −/− mice ( P −/− Apoe −/− mice. Bone marrow transplantation experiments revealed that nonhematopoietic cell–derived Fn-EDA exacerbates stroke through Toll-like receptor-4 expressed on hematopoietic cells. Infusion of a specific inhibitor of Fn-EDA into Apoe −/− mouse 15 minutes after reperfusion significantly improved stroke outcome. Conclusions— Hypercholesterolemic mice deficient in Fn-EDA exhibit reduced cerebral thrombosis and less inflammatory response after ischemia/reperfusion injury. These findings suggest that targeting Fn-EDA could be an effective therapeutic strategy in stroke associated with hypercholesterolemia.

To investigate the effects of blocking Rho kinase pathway on the expression of inflammatory signaling pathways in the retina of diabetic mice and in human retinal Müller glial cells stimulated with high-glucose to replicate hyperglycemia.Retinas from diabetic mice and human retinal Müller glial cells (MIO-M1) were studied. Western blot analysis, immunofluorescence, and enzyme-linked immunosorbent assay were utilized to study the effect of the Rho kinase inhibitor fasudil on the expression of Rho-associated protein kinase-1 (ROCK-1), extracellular signal-regulated kinases12(ERK ½), phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (p-NF-κB), inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1/CCL2).Treatment of human retinal Müller cells with high-glucose induced significant upregulation of ROCK-1, VEGF, and MCP-1/CCL2. Fasudil co-treatment normalized the high-glucose-induced upregulation of these mediators. Similarly, fasudil attenuated high-glucose-induced enhanced immunoreactivity for ROCK-1 and VEGF. Diabetes induced upregulation of ROCK-1, p-ERK ½, p-NF-κB and iNOS expression in retinas of mice. Constant fasudil intake from the onset of diabetes did not affect the metabolic status of diabetic mice but it attenuated diabetes-induced upregulation of these inflammatory signaling pathways.Our finding suggests that Rho-associated protein kinase-1 activation mediates regulation of inflammatory signaling pathways in diabetic retina.

Purpose Extracellular matrix metalloproteinase inducer (EMMPRIN) promotes angiogenesis through matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) production. We investigated the expression levels of EMMPRIN and correlated these levels with VEGF, MMP-1 and MMP-9 in proliferative diabetic retinopathy (PDR). In addition, we examined the expression of EMMPRIN in the retinas of diabetic rats and the effect of EMMPRIN on the induction of angiogenesis regulatory factors in human retinal microvascular endothelial cells (HRMECs). Methods Vitreous samples from 40 PDR and 19 non-diabetic patients, epiretinal membranes from 12 patients with PDR, retinas of rats and HRMECs were studied by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, Western blot analysis, zymography analysis and RT-PCR. Results We showed a significant increase in the expression of EMMPRIN, VEGF, MMP-1 and MMP-9 in vitreous samples from PDR patients compared with non-diabetic controls (p

We investigated the expression of the proinflammatory and proangiogenic factor osteoprotegerin (OPG) and its ligands, receptor activator of nuclear factor-κB ligand (RANKL), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and the receptor RANK in proliferative diabetic retinopathy (PDR).Vitreous samples from PDR and nondiabetic control patients and epiretinal membranes from PDR patients were studied by enzyme-linked immunosorbent assay, immunohistochemistry, and Western blot analysis.Vascular endothelial growth factor, OPG, and soluble RANK levels in vitreous samples from PDR patients were significantly higher than that in nondiabetic controls. Soluble TRAIL levels were significantly lower in PDR patients than that in nondiabetic control, whereas soluble RANKL levels did not differ significantly. RANKL, RANK, and TRAIL were expressed in vascular endothelial cells, myofibroblasts, and CD45-expressing leukocytes in PDR epiretinal membranes.Dysregulated expression of OPG/RANKL/RANK pathway and TRAIL might be related to inflammation and angiogenesis in PDR.

Purpose We investigated the link among the proinflammatory cytokine high-mobility group box 1 (HMGB1) and 8-hydroxy-2’-deoxyguanosine (8-OHdG) as a marker of oxidative DNA damage, the endothelial adhesion molecule and oxidase enzyme vascular adhesion protein-1 (VAP-1), and the inducible cytoprotective molecule heme oxygenase-1 (HO-1) in proliferative diabetic retinopathy (PDR). We correlated the levels of these molecules with clinical disease activity and studied the proinflammatory activities of HMGB1 on rat retinas and human retinal microvascular endothelial cells (HRMECs). Methods Vitreous samples from 47 PDR and 19 non-diabetic patients, epiretinal membranes from 11 patients with PDR, human retinas (16 from diabetic patients and 16 from non-diabetic subjects), rat retinas, and HRMECs were studied by enzyme-linked immunosorbent assay, immunohistochemistry, western blot immunofluorescence, and RT-PCR analyses. In addition, we assessed the adherence of leukocytes to HMGB1-stimulated HRMECs. Results HMGB1, 8-OHdG, and soluble VAP-1 (sVAP-1) levels were significantly higher in vitreous samples from PDR patients than in those from non-diabetics (p = 0.001

Oxidative loads in the brain are involved in age related impairments like learning and memory as well as neurodegeneration. Taurine, the most abundant free amino acid in humans has many potential health benefits through its anti-oxidant and anti-inflammatory properties. Therefore, we investigated the neuroprotective potential of taurine on oxidative stress, neuronal loss and memory impairments in streptozotocin model of cognitive impairments in rats. The cognitive impairment was developed by giving single intracerebroventricular (ICV) injection of streptozotocin (STZ) 3 mg/kg body weight bilaterally. An increased latency and path length was observed in ICV-STZ group animals as compared to sham group animals and these were inhibited significantly in STZ group pre-treated with taurine (50 mg/kg body weight orally once daily for 15 days). Moreover, the significantly depleted content of GSH and elevated level of thiobarbituric acid reactive substances (TBARS) in ICV-STZ group animals were protected significantly with pre-treatment of taurine. The activity of antioxidant enzymes, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, catalase, and superoxide dismutase was decreased in STZ group as compared to sham group and pre-treatment of STZ group with taurine has protected their activities significantly. Furthermore, the increased activity of acetylcholine esterase and decreased expression of choline acetyl transferase were attenuated by the pre-treatment of taurine. Taurine also protected the morphology of the hippocampal pyramidal neurons. This study concludes that the prophylactic intervention of taurine may be used to prevent the deterioration of cognitive functions and neurobehavioral activities, often associated with the generation of free radicals.

Oxidative stress and inflammation play an integral role in the pathogenesis of cerebral ischemia that leads to a cascade of events culminating in the death of neurons and their supporting structures. The signaling pathways that link these events are not fully understood. Recent studies have demonstrated a close link between the nuclear factor-κB (NF-κB) signaling pathway and cerebral ischemia/reperfusion (I/R)-induced inflammation. Flavonoids have been suggested to exert human health benefits by anti-oxidant and anti-inflammatory mechanisms. In this study we undertook a pharmacological approach to investigate the ability of naringenin, a potent flavonoid, to prevent oxidative stress and NF-κB-mediated inflammatory brain damage in the rat model of focal cerebral I/R injury. To test this hypothesis, male Wistar rats were pretreated with naringenin once daily for 21 days and then subjected to 1h of middle cerebral artery occlusion followed by 23 h of reperfusion. Naringenin treatment successfully upregulates the antioxidant status, decreases the infarct size and lowers the levels of myeloperoxidase, nitric oxide and cytokines, besides functional recovery returned close to the baseline. Moreover, immunohistochemical and Western blot analyses clearly demonstrated that naringenin treatment limits glial activation and downregulates the NF-κB expression level and their target genes. These results show, prophylactic treatment with naringenin improved functional outcomes and abrogated the ischemic brain injury by suppressing NF-κB-mediated neuroinflammation. The present study suggests that naringenin may be used as a potential neuroprotectant in patients at high risk of ischemic stroke.

Oxidative stress is involved in Alzheimer's disease (AD)-type neurodegeneration with cognitive impairment (AD-TNDCI) as well as age related cognitive deficit. The present study was designed to investigate the pre-treatment effects of naringenin (NAR), a polyphenolic compound on cognitive dysfunction, oxidative stress in the hippocampus, and hippocampal neuron injury in a rat model of AD-TNDCI. The rats were pre-treated with NAR at a selective dose (50mg/kg, orally) for 2 weeks followed by intracerebroventricular-streptozotocin (ICV-STZ) (3mg/kg; 5μl per site) injection bilaterally. Behavioral alterations were monitored after 2 weeks from the lesion using passive avoidance test and Morris water maze paradigm. Three weeks after the lesion, the rats were sacrificed for measuring non-enzymatic [4-hydroxynonenal (4-HNE), malonaldehyde (MDA), thiobarbituric reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), protein carbonyl (PC), reduced glutathione (GSH)] content and enzymatic [glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and Na(+)/K(+)-ATPase] activity in the hippocampus, and expression of choline acetyltransferase (ChAT) positive neuron, and histopathology of hippocampal neurons. The non-enzymatic level and enzymatic activity was significantly increased and decreased, respectively, with striking impairments in spatial learning and memory, loss of ChAT positive neuron and severe damage to hippocampal neurons in the rat induced by ICV-STZ. These abnormalities were significantly improved by NAR pre-treatment. The study suggests that NAR can protect against cognitive deficits, neuronal injury and oxidative stress induced by ICV-STZ, and may be used as a potential agent in treatment of neurodegenerative diseases such as AD-TNDCI.

Epidemiologic studies have shown that foods rich in polyphenols, such as flavonoids, can lower the risk of ischemic disease; however, the mechanism of protection has not been clearly investigated. In this study, we hypothesized that pretreatment effect of catechin hydrate (CH) on functional outcome, neuronal damage and on secondary injuries in the ischemic brain of rats. To test this hypothesis, male Wistar rats were pretreated with CH (20 mg/kg b.wt) for 21 days and then subjected to 2 h middle cerebral artery occlusion (MCAO) followed by 22 h of reperfusion. After 2 h MCAO/22 h reperfusion, neurological deficit, infarct sizes, activities of antioxidant enzymes and cytokines level were measured. Immunohistochemistry and western blot were used to analyse the expression of glial fibrillary acidic protein (GFAP), inducible nitric oxide (iNOS) and NF-kB in ischemic brain. The administration of CH showed marked reduction in infarct size, reduced the neurological deficits, suppressed neuronal loss and downregulate the iNOS, GFAP and NF-kB expression in MCAO rats. A significantly depleted activity of antioxidant enzymes and content of glutathione in MCAO group were protected significantly in MCAO group pretreated with CH. Conversely, the elevated level of thiobarbituric acid reactive species and cytokines in MCAO group was attenuated significantly in CH pretreated group when compared with MCAO group. The results indicated that CH protected the brain from damage caused by MCAO, and this effect may be through downregulation of NF-kB expression.

Oxidative stress and inflammatory damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The present study examined the hypothesis that S-allyl cysteine (SAC), organosulfur compounds found in garlic extract, would reduce oxidative stress-associated brain injury after middle cerebral artery occlusion (MCAO). To test this hypothesis, male Wistar rats were subjected to MCAO for 2 hours and 22-hour reperfusion. S-allyl cysteine was administered (100 mg/kg, b.wt.) intraperitoneally 30 minutes before the onset of ischemia and after the ischemia at the interval of 0, 6, and 12 hours. After 24 hours of reperfusion, rats were tested for neurobehavioral activities and were killed for the infarct volume, estimation of lipid peroxidation, glutathione content, and activity of antioxidant enzymes (glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase). S-allyl cysteine treatment significantly reduced ischemic lesion volume, improved neurologic deficits, combated oxidative loads, and suppressed neuronal loss. Behavioral and biochemical alterations observed after MCAO were further associated with an increase in glial fibrillary acidic protein and inducible nitric oxide expression and were markedly inhibited by the treatment with SAC. The results suggest that SAC exhibits exuberant neuroprotective potential in rat ischemia/reperfusion model. Thus, this finding of SAC-induced adaptation to ischemic stress and inflammation could suggest a novel avenue for clinical intervention during ischemia and reperfusion.

Stroke is an enormous public health problem with an imperative need for more effective therapy. Free radicals have been reported to play a role in the expansion of ischemic brain lesions, and the effect of free radical scavengers is still under debate. The present study investigated the neuroprotective effect of Ocimum sanctum (OS) to reduce brain injury after middle cerebral artery occlusion (MCAO). Male Wistar rats were subjected to MCAO for 2 h and reperfused for 22 h. The administration of OS (200 mg/kg bwt., orally) once daily for 15 days before MCAO showed marked reduction in infarct size, reduced the neurological deficits, and suppressed neuronal loss in MCAO rats. A significantly depleted activity of antioxidant enzymes and content of glutathione in MCAO group were protected significantly in MCAO group pretreated with OS. Conversely, the elevated level of thiobarbituric acid-reactive substances (TBARS) in MCAO group was attenuated significantly in OS-pretreated group when compared with MCAO group. Consequently, OS pretreatment may reduce the deterioration caused by free radicals, and thus may used to prevent subsequent behavioral, biochemical and histopathological changes that transpire during cerebral ischemia. This finding reflects that supplementation of OS intuitively by reasonable and understandable treatment effectively ameliorates the cerebral ischemia-induced oxidative damage.

Cerebral stroke is the third largest cause of death and the severe leading cause of disability, thus have astronomical financial and social burden worldwide. Accumulated evidence suggests that ROS can be scavenged through utilizing natural antioxidant compounds present in foods and medicinal plants. In this study, we examined whether silymarin, an antioxidant, present in the milk of thistle can prevent or slowdown neuronal injury in focal cerebral ischemia. Male Wistar rats were pre-treated with silymarin (200 mg/kg body weight, dissolved in 0.3 % sodium carboxymethyl cellulose, once orally) for 15 days. On day 16, they underwent a transient 2 h suture-occlusion of the middle cerebral artery followed by 22 h of reperfusion. Rats were tested for neurobehavioral activity after 22 h reperfusion. Silymarin was found to be successful in upregulating the antioxidant status and lowering the apoptotic responses, and functional recovery returned close to the baseline. This study revealed that silymarin, a naturally occurring flavone from the milk thistle ( Silybum marianum ), may be helpful in slowing down the progression of neurodegeneration in focal cerebral ischemia. These results suggest that the neuroprotective potential of silymarin is mediated through its anti-oxidative and anti-apoptotic properties.

Incidence of stroke is considered to be a major cause of death throughout the world. The middle cerebral artery occlusion (MCAO) for 2h followed by 22h of reperfusion model was used in male Wistar rats to study the protection of stroke by hesperidin. Hesperidin administration (50mg/kg b.wt.) once daily for 15days has improved the infarct size, reduced the neurological deficits in terms of behaviors, and protected the elevated level of thiobarbituric acid reactive species (TBARS). A significantly depleted activity of antioxidant enzymes, glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD) and content of glutathione (GSH) in MCAO group were protected significantly in MCAO group pretreated with hesperidin. Moreover, inflammatory mediators like TNF-α, IL-1β levels, expression of iNOS and glial fibrillary acidic protein (GFAP) were significantly attenuated in H+MCAO group as compared to MCAO group. In conclusion, prophylactic treatment with hesperidin ameliorated the functional and histological outcomes with elevated endogenous antioxidants status as well as reduced induction of proinflammatory cytokines in MCA occluded rat. We theorized that hesperidin is among the pharmacological agents that reduce free radicals and its associated inflammation and have been found to limit the extent of brain damage following stroke.

The synergistic scavenger effects of selenium and melatonin collectively we called Se-Mel was studied on the prevention of neuronal injury induced by ischemia/reperfusion. Male Wistar rats were treated with sodium selenite (0.1 mg/kg, i.p.) and melatonin (10 mg/kg, i.p.) 30 min before the middle carotid artery occlusion (MCAO) and immediately after MCAO to male Wistar rats and was continued for 3 days once daily at the interval of 24 h. Behavioral activity (spontaneous motor activity and motor deficit) was improved in Se-Mel-treated rats as compared to MCAO group rats. The level of glutathione and the activity of antioxidant enzymes was depleted significantly while the content of thiobarbituric acid reactive substances, protein carbonyl, and nitric oxide radical (NO(·)) was increased significantly in MCAO group. Systemic administration of Se-Mel ameliorated oxidative stress and improves ischemia/reperfusion-induced focal cerebral ischemia. Se-Mel also inhibited inducible nitric oxide synthase expression in Se-Mel+MCAO group as compared to MCAO group rats. Thus, Se-Mel has shown an excellent neuroprotective effect against ischemia/reperfusion injury through an anti-ischemic pathway. In conclusion, we demonstrated that the pretreatment with Se-Mel at the onset of reperfusion, reduced post-ischemic damage, and improved neurological outcome following transient focal cerebral ischemia in male Wistar rat.

The present study was undertaken to investigate the neuroprotective effects of resveratrol (RES) on 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease (PD) in rats. PD is an age-related neurodegenerative disorder in which the role of reactive oxygen species (ROS) is strongly implicated. RES, a polyphenolic antioxidant compound enriched in grapes, has been shown to have antioxidant and anti-inflammatory actions and thus was tested for its beneficial effects using 6-OHDA-induced PD rat model. Male Wistar rats were pretreated with RES (20mg/kg body weight i.p.) once daily for 15 days and subjected to unilateral intrastriatal injection of 6-OHDA (10 microg in 0.1% ascorbic acid in normal saline). Three weeks after 6-OHDA infusion, rats were tested for neurobehavioral activity and were killed after 4 weeks of 6-OHDA infusion for the estimation of lipid peroxidation, glutathione content, and activity of antioxidant enzymes (glutathione peroxidase [GPx], glutathione reductase [GR], catalase [CAT], and superoxide dismutase [SOD]. RES was found to be successful in upregulating the antioxidant status and lowering the dopamine loss. Conversely, the elevated level of thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC), and activity of phospholipase A2 in 6-OHDA group was attenuated significantly in RES-pretreated group when compared with 6-OHDA-lesioned group. These results were supported by the immunohistochemical findings in the substantia nigra that has shown the protection of neurons by RES from deleterious effects of 6-OHDA. Thus, RES may be used to reduce the deterioration caused by free radicals thereby preventing subsequent behavioral, biochemical, and histopathological changes that occur during PD.

Free radical induced neural damage is implicated in cerebral ischemia-reperfusion (IR) injury and antioxidants are reported to have neuroprotective activity. The present study was designed to assess the neuroprotective role of rutin (Vitamin P), and mechanism of action. The middle cerebral artery (MCA) of an adult male Wistar rat was occluded for 2 h and reperfused for 22 h. The administration of rutin (25 mg/kg bwt., orally) once daily for 21 days before middle cerebral artery occlusion (MCAO) showed marked reduction in infarct size, reduced the neurological deficits in terms of behaviors, suppressed neuronal loss and diminished the p53 expression in MCAO rats. A significantly depleted activity of antioxidant enzymes, glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD) and content of glutathione (GSH) in MCAO group were protected significantly in MCAO group pretreated with rutin. Conversely, the elevated level of thiobarbituric acid reactive species (TBARS), H(2)O(2) and protein carbonyl (PC) in MCAO group was attenuated significantly in rutin-pretreated group when compared with MCAO group. These results indicate that rutin attenuates ischemic neural apoptosis by reducing the expression of p53, preventing morphological changes and increasing endogenous antioxidant enzymatic activities. Thus, rutin treatment may represent a novel approach in lowering the risk or improving the function of ischemia-reperfusion brain injury-related disorders.

Selenium (Se), a nutritionally essential trace element with known antioxidant potential, protects the brain from oxidative damage in various models of neurodegeneration. Intracerebroventricular-streptozotocin (ICV-STZ) in rats causes impairment of brain glucose and energy metabolism along with oxidative damage and cholinergic dysfunction, and provides a relevant model for sporadic dementia of Alzheimer's type (SDAT). The present study demonstrates the therapeutic efficacy of Se on cognitive deficits and oxidative damage in ICV-STZ in rats. Male Wistar rats were pre-treated with sodium selenite, a salt of Se (0.1 mg/kg; body weight) for 7 days and then were injected bilaterally with ICV-STZ (3 mg/kg), while sham rats received the same volume of vehicle. After two ICV-STZ infusions, rats were tested for memory deficits in passive avoidance and Morris water maze (MWM) tests and then were sacrificed for biochemical and histopatholgical assays. ICV-STZ-infused rats showed significant loss in learning and memory ability, which were significantly improved by Se supplementation. A significant increase in thio-barbituric acid reactive species (TBARS), protein carbonyl (PC) and a significant decrease in reduced glutathione (GSH), antioxidant enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]) and adenosine triphosphate (ATP) in the hippocampus and cerebral cortex and choline acetyltransferase (ChAT) in hippocampus were observed in ICV-STZ rats. Se supplementation significantly ameliorated all alterations induced by ICV-STZ in rats. Our study reveals that Se, as a powerful antioxidant, prevents cognitive deficits, oxidative damage and morphological changes in the ICV-STZ rats. Thus, it may have a therapeutic value for the treatment of SDAT.

Oxidative stress is a critical contributing factor to age-related neurodegenerative disorders. Therefore, the inhibition of oxidative damage, responsible for chronic detrimental neurodegeneration, is an important strategy for neuroprotective therapy. Withania somnifera (WS) extract has been reported to have potent antioxidant and free radical quenching properties in various disease conditions. The present study evaluated the hypothesis that WS extract would reduce oxidative stress-associated neurodegeneration after intracerebroventricular injection of streptozotocin (ICV-STZ) in rats. To test this hypothesis, male Wistar rats were pretreated with WS extract at doses of 100, 200, and 300 mg/kg body weight once daily for 3 weeks. On day 22nd, the rats were infused bilaterally with ICV-STZ injection (3 mg/kg body weight) in normal saline while sham group received only saline. Two weeks after the lesioning, STZ-infused rats showed cognitive impairment in the Morris water maze test. The rats were sacrificed after 3 weeks of the lesioning for the estimation of the contents of lipid peroxidation, reduced glutathione, and activities of glutathione reductase, glutathione peroxidase, and catalase. Pretreatment with WS extract attenuated behavioral, biochemical, and histological alterations significantly in dose-dependent manner in the hippocampus and cerebral cortex of ICV-STZ-infused rats. These results suggest that WS affords a beneficial effect on cognitive deficit by ameliorating oxidative damage induced by streptozotocin in a model of cognitive impairment.

Stroke is a life-threatening disease with major cause of mortality and morbidity worldwide. The neuronal damage following cerebral ischemia is a serious risk to stroke patients. Oxidative stress and apoptotic damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The objective of this study was to test the hypothesis that administration of edaravone (Edv) maintains antioxidant status in brain, improves the cholinergic dysfunction and suppresses the progression of apoptosis response in rat. To test this hypothesis, male Wistar rats were subjected to middle cerebral artery occlusion (MCAO) of 2 h followed by reperfusion for 22 h. Edv was administered (10 mg/kg bwt) intraperitoneally 30 min before the onset of ischemia and 1 h after reperfusion. After reperfusion, rats were tested for neurobehavioral activities and were sacrificed for the infarct volume, estimation of oxidative damage markers. Edv treatment significantly reduced ischemic lesion volume, improved neurological deficits, contended oxidative loads, and suppressed apoptotic damage. In conclusion, treatment with Edv ameliorated the neurological and histological outcomes with elevated endogenous anti-oxidants status as well as reduced induction of apoptotic responses in MCA occluded rat. We theorized that Edv is among the pharmacological agents that reduce free radicals and its associated cholinergic dysfunction and apoptotic damage and have been found to limit the extent of brain damage following stroke.

The objective of the present study was to assess the neuroprotective role of rutin (vitamin P) and delineate the mechanism of action. Recent evidence indicates that rutin exhibits antioxidant potential and protects the brain against various oxidative stressors. More precisely, the aim of the present study was to examine the modulating impacts of rutin against cognitive deficits and oxidative damage in intracerebroventricular-streptozotocin (ICV-STZ)-infused rats. Rats were injected bilaterally with ICV-STZ (3 mg/kg), whereas sham rats received the same volume of vehicle. After 2 weeks of streptozotocin (STZ) infusion, rats were tested for cognitive performance using Morris water maze tasks and thereafter euthanized for further biochemical, histopathological, and immunohistochemical studies. Rutin pretreatment (25 mg/kg, orally, once daily for 3 weeks) significantly attenuated thiobarbituric acid reactive substances (TBARS), activity of poly ADP-ribosyl polymerase, and nitrite level and decreased level of reduced glutathione (GSH) and activities of its dependent enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]) and catalase in the hippocampus of ICV-STZ rats. ICV-STZ rats showed significant cognitive deficits, which was improved significantly by rutin supplementation. The results indicate that rutin attenuates STZ-induced inflammation by reducing the expression of cyclooxygenase-2 (COX-2), glial fibrillary acidic protein (GFAP), interleukin-8 (IL-8), inducible nitric oxide synthase (iNOS), nuclear factor-kB, and preventing the morphological changes in hippocampus. The study thereby suggests the effectiveness of rutin in preventing cognitive deficits and might be beneficial for the treatment of sporadic dementia of Alzheimer type (SDAT).

Oxidative stress leads to complex biochemical alterations, and has been implicated in the progressive loss of learning and memory. Supplementing and boosting the endogenous antioxidant defense system could impede the progression of various types of neurodegeneration. In the present study, we have investigated the neuroprotective efficacy of a low-dose combination of certain promising and powerful natural antioxidants in an experimental model of cognitive impairment. Combined pretreatment with the extract of Nardosatchys jatamansi (N), crocetin (C) and selenium (Se) as sodium selenite (N, 200 mg/kg + C, 25 μg/kg + Se, 0.05 mg/kg body weight) for 15 days led to improved behavioral outcomes in streptozotocin (STZ)-induced cognitive impairment in rats. While intracerebroventricular (ICV) infusion of STZ resulted in the significant elevation of markers of oxidative stress and depletion of endogenous antioxidant defense system in the vehicle-pretreated group, these markers of oxidative stress and antioxidant enzymatic as well as non-enzymatic defense lines were attenuated in the group pretreated with the combination of antioxidants (NCSe). NCSe pretreatment markedly improved the performance of animals in passive avoidance test and Morris water maze (MWM) tasks, significantly reduced the level of TBARS, and elevated the content of glutathione and activities of antioxidant enzymes (glutathione peroxidase, glutathione-S-transferase and catalase). Our study reflects the synergistic potential of the above combination and concludes that a multimodal approach could be beneficial rather than a singular intervention.

In the present study, we examined the molecular mechanism by which Piperine (bioactive compound of Piper nigrum) inhibits neuronal cell apoptosis. We further investigated the anti-inflammatory effect of Piperine on 6-OHDA induced Parkinson's disease. Consistent with its antioxidant properties, Piperine (10 mg/kg bwt) reduced 6-OHDA-induced lipid peroxidation and stimulated glutathione levels in striatum of rats. Furthermore, Piperine treatment diminished cytochrome-c release from mitochondria and reduced caspase-3 and caspase-9 activation induced by 6-OHDA. Treatment with Piperine markedly inhibited poly(ADP-ribose) polymerase activation, pro-apoptotic Bax levels and elevation of Bcl-2 levels. Piperine reduces contralateral rotations induced by apomorphine. Further narrow beam test and rotarod also showed improvement in motor coordination and balance behavior in rats treated with Piperine. In addition Piperine depletes inflammatory markers, TNF-α and IL-1β in 6-OHDA-induced Parkinson's rats. We propose that, in addition to its antioxidant properties Piperine exerts a protective effect via anti-apoptotic and anti-inflammatory mechanism on 6-OHDA induced Parkinson's disease.

Experimental studies have demonstrated that oxidative stress and apoptosis play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The purpose of this study was to determine whether the quercetin dihydrate (Q) protects against cerebral ischemia neuronal damage. Male Wistar rats were subjected to transient middle cerebral artery occlusion (MCAO) for 2 h and reperfused for 72 h. Quercetin (30 mg/kg, i.p) was administrated 30 min before the onset of ischemia and after the ischemia at interval of 0, 24, 48, and 72 h. The administration of Q showed marked reduction in infarct size, reduced the neurological deficits in terms of behaviors, suppressed neuronal loss and diminished the p53 expression in MCAO rats. Q was found to be successful in upregulating the antioxidant status and lowering the TBARS level. Conversely, the elevated activity of poly (ADP-ribose) polymerase (PARP), and activity of caspase-3 in MCAO group was attenuated significantly in Q treated group when compared with MCAO group. Our study reveals that Q, as a powerful antioxidant, could prevent free radicals associated oxidative damage and morphological changes in the MCAO rats. Thus, it may have a therapeutic value for the treatment of stroke.

Curcumin, the active principle of turmeric used in Indian curry is known for its antitumor, antioxidant, antiarthritic, anti-ischemic and anti-inflammatory properties and might inhibit the accumulation of destructive beta-amyloid in the brains of Alzheimer's disease patients. A Parkinsonian model in rats was developed by giving 6-hydroxydopamine (10 μg/2 μl in 0.1% ascorbic acid–saline) in the right striatum. After 3 weeks of lesioning, the behavior activities (rotarod, narrow beam test, grip test and contra-lateral rotations) were increased in a lesioned group as compared to a sham group and these activities were protected significantly with the pretreatment of curcumin. A significant protection on lipid peroxidation, glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, tyrosine hydroxylase and D2 receptor binding was observed in the striatum of lesioned group animals pretreated with 80 mg/kg body weight of curcumin for 21 days as compared to lesion group animals. No significant alterations on behavior and biochemical parameters were observed in sham group animals and the animals of sham group pretreated with curcumin. This study indicates that curcumin, which is an important ingredient of diet in India and also used in various systems of indigenous medicine, is helpful in preventing Parkinsonism and has therapeutic potential in combating this devastating neurologic disorder.

This study was undertaken to investigate the neuroprotective effects of rutin (vitamin P) on 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease (PD) in rats. Oxidative stress and inflammation is an important event, play a crucial role in neurodegenerative diseases. Rutin has been shown to have antioxidant and anti-inflammatory actions, and thus was tested for its beneficial effects using 6-OHDA-induced PD rat model. Male Wistar rats were pre-treated with rutin (25 mg/kg bwt, orally) for 3 weeks and subjected to unilateral intrastriatal injection of 6-OHDA (10 μg in 0.1% ascorbic acid in normal saline). Three weeks after 6-OHDA infusion, rats were tested for neurobehavioral activity, and were killed after 4 weeks of 6-OHDA infusion for the estimation of thiobarbituric acid reactive substances, glutathione, and its dependent enzymes (glutathione peroxidase and glutathione reductase), dopamine (DA) and its metabolite 3,4-dihydroxyphenyl acetic acid. The increase in 6-OHDA-induced rotations and deficits in locomotor activity and motor coordination and decrease in antioxidant level, DA content and its metabolite and increase in the number of dopaminergic D2 receptors in striatum were protected significantly with lesioned group pre-treated with rutin. These findings were further supported by the histopathological and immunohistochemical findings in the substantia nigra that showed that rutin protected neurons from deleterious effects of 6-OHDA. These results suggest that the consumption of rutin, which is novel vitamin, may have the possibility of protective effect against the neurological disorder such as PD.

Restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species (ROS) with consequent reperfusion injury. ROS cause lipid peroxidation, protein oxidation, and DNA damage, all of which are deleterious to cells. So diminishing the production of free radicals and scavenging them may be a successful therapeutic strategy for the protection of brain tissue in cerebral stroke. The present study investigated the neuroprotective effect of sesamin (Sn) to reduce brain injury after middle cerebral artery occlusion (MCAO). The middle cerebral artery (MCA) of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. Sesamin is the most abundant lignan in sesame seed oil is a potent antioxidant. Sesamin (30 mg/kg) was given orally twice, 30 min before the onset of ischemia and 12 h after reperfusion. The initial investigations revealed that sesamin reduced the neurological deficits in terms of behavior and reduced the level of thiobarbituric acid reactive species (TBARS), and protein carbonyl (PC) in the different areas of the brain when compared with the MCAO group. A significantly depleted level of glutathione and its dependent enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]) in MCAO group were protected significantly in MCAO group treated with sesamin. The present study suggests that sesamin may be able to attenuate the ischemic cell death and plays a crucial role as a neuroprotectant in regulating levels of reactive oxygen species in the rat brain. Thus, sesamin may be a potential compound in stroke therapy.

Recent evidence indicates that curcumin (CUR), the principal curcuminoid of turmeric, exhibits antioxidant potential and protects the brain against various oxidative stressors. The aim of the present study was to examine the modulating impacts of CUR against cognitive deficits and oxidative damage in intracerebroventricular-streptozotocin (ICV-STZ) infused rats. Rats were injected bilaterally with ICV-STZ (3 mg/kg), while sham rats received the same volume of vehicle and then supplemented with CUR (80 mg/kg) for three weeks. After two weeks of ICV-STZ infusion, rats were tested for cognitive performance using passive avoidance and water maze tasks and then sacrificed for biochemical and histopathological assays. ICV-STZ rats showed significant cognitive deficits, which were significantly improved by CUR supplementation. CUR supplementation significantly augmented increased 4-hydroxynonenal (4-HNE) and malonaldehyde (MDA), thiobarbituric reactive substances (TBARS), hydrogen peroxide (H2O2), protein carbonyl (PC) and oxidized glutathione (GSSG); decreased levels of reduced glutathione (GSH) and its dependent enzymes (Glutathione peroxidase [GPx] and glutathione reductase [GR]) in the hippocampus and cerebral cortex; and increased choline acetyltransferase (ChAT) activity in the hippocampus of ICV-STZ rats. The study suggests that CUR is effective in preventing cognitive deficits, and might be beneficial for the treatment of sporadic dementia of Alzheimer's type (SDAT).