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This study investigates the effect of chronic consumption of a high‐fat diet rich in corn oil (CO‐HFD) on atrial cells ultrastructure, antioxidant levels and markers of intrinsic cell death of both control and type 1 diabetes mellitus (T1DM)‐induced rats. Adult male rats (10 rats/group) were divided into four groups: control fed standard diet (STD) (3.82 kcal/g, 9.4% fat), CO‐HFD (5.4 kcal/g, 40% fat), T1DM fed STD, and T1DM + CO‐HFD. CO‐HFD and T1DM alone or in combination impaired systolic and diastolic functions of rats and significantly reduced levels of GSH and the activity of SOD, enhanced lipid peroxidation, increased protein levels of P53, Bax, cleaved caspase‐3, and ANF and decreased levels of Bcl‐2 in their atria. Concomitantly, atrial cells exhibited fragmentation of the myofibrils, disorganized mitochondria, decreased number of atrionatriuretic factor (ANF) granules, and loss of gap junctions accompanied by changes in capillary walls. Among all treatments, the severity of all these findings was more severe in T1DM and most profound in the atria of T1DM + CO‐HFD. In conclusion, chronic consumption of CO‐HFD by T1DM‐induced rats elicits significant biochemical and ultrastructural damage to rat atrial cells accompanied by elevated oxidative stress and mitochondria‐mediated cell death. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the role of the liver in lowering fasting blood glucose levels (FBG) in rats native to high (HA) and low altitude (LA) areas. As compared with LA natives, besides the improved insulin and glucose tolerance, HA native rats had lower FBG, at least mediated by inhibition of hepatic gluconeogenesis and activation of glycogen synthesis. An effect that is mediated by the enhancement of hepatic insulin signaling mediated by the decreased phosphorylation of TSC induced inhibition of mTOR function. Such effect was independent of activation of AMPK nor stabilization of HIF1α, but most probably due to oxidative stress induced REDD1 expression. However, under insulin stimulation, and in spite of the less activated mTOR function in HA native rats, LA native rats had higher glycogen content and reduced levels of gluconeogenic enzymes with a more enhanced insulin signaling, mainly due to higher levels of p-IRS1 (tyr612). [ABSTRACT FROM AUTHOR]

Context: Camel milk is used in traditional medicine to treat diabetes mellitus hypertension and other metabolic disorders. Objective: This study evaluated the antisteatotic and antihypertensive effects of camel milk protein hydrolysate (CMH) in high fructose (HF)-fed rats and compared it with the effects afforded by the intact camel milk protein extract (ICM). ICM (1000mg/kg), 3) CMH (1000mg/kg), 4) HF (15% in drinking water), 5) HF (15%) þ ICM (1000 mg/kg), and 6) HF (15%) þ CMH (1000mg/kg). All treatments were given orally for 21 weeks, daily. Results: Both ICM and CMH reduced fasting glucose and insulin levels, serum and hepatic levels of cholesterol and triglycerides, and serum levels of ALT and AST, angiotensin II, ACE, endothelin-1, and uric acid in HF-fed rats. In addition, both ICM and CMH reduced hepatic fat deposition in the hepatocytes and reduced hepatocyte damage. This was associated with an increase in the hepatic activity of AMPK, higher PPARa mRNA, reduced expression of fructokinase C, SREBP1, SREBP2, fatty acid synthase, and HMG-CoAreductase. Both treatments lowered systolic and diastolic blood pressure. However, the effects of CMH on all these parameters were greater as compared to ICM. Discussion and conclusions: The findings of this study encourage the use of CMH in a large-scale population and clinical studies to treat metabolic steatosis and hypertension. [ABSTRACT FROM AUTHOR]

Esculeoside A (ESA) is a tomato-derived glycoside with antioxidant and anti-inflammatory properties. The protective effect of ESA against diabetic retinopathy is not well-investigated and was the core objective of this study. In addition, we tested if such protection involves the activation of Nrf2 signaling. Type 1 diabetes mellitus (T1DM) was induced in adult Wistar male rats by an intraperitoneal injection of streptozotocin (65 mg/kg). Non-diabetic and T1DM rats were divided into two subgroup groups given either the vehicle or ESA (100 mg)/kg. An additional T1DM group was given ESA (100 mg/kg) and an Nrf2 inhibitor (2 mg/kg) (n=8 rats/group). Treatments continued for 12 weeks. In this study, according to the histological features, ESA improved the structure of ganglionic cells and increased the number of cells of the inner nuclear and plexiform layers in the retinas of T1DM rats. Concomitantly, it reduced the retina levels of malondialdehyde (lipid peroxides), vascular endothelial growth factor, interleukin-6, tumor necrosis factor-α, Bax, and caspase-3. In the retinas of the control and diabetic rats, ESA boosted the levels of total glutathione, superoxide dismutase, heme-oxygenase-1, and Bcl2, reduced the mRNA levels of REDD1, and enhanced cytoplasmic and nuclear levels of Nrf2. However, ESA failed to alter the mRNA levels of Nrf2 and keap1, protein levels of keap1, plasma glucose, plasma insulin, serum triglycerides, cholesterol, and LDL-c in both the control and T1DM rats. In conclusion, ESA alleviates retinopathy in T1DM rats by suppressing REDD1-associated degradation and inhibiting the Nrf2/antioxidant axis. [Display omitted] • Esculeoside A (ESA) attenuates retinal damage in STZ-diabetic rats and improves retinal histology. • ESA effects include suppressing oxidative stress, inflammation, and apoptosis. • This is associated with keap1-independent activation of the Nrf2/antioxidant axis. • The effect of ESA is parallel with the upregulation of REDD1. • Brusatol, an Nrf2 inhibitor, completely abolished all the ocular benefits of ESA. [ABSTRACT FROM AUTHOR]

This study investigated the protective effect of Kaempferol against CdCl2-induced hippocampal damage and memory deficit in rats and investigated if such effects involve modulating the activity of AMPK/PTEN/Akt/mTOR axis. Adult male rats (n = 12/group) were divided into control or CdCl2-treated rats received the vehicle of Kaempferol for consecutive 6 weeks. Also, hippocampal cells were treated with CdCl2 in the presence or absence of Kaempferol for 24 h with or without 1 h pre-incubation with compound C, an AMPK inhibitor or with bpV a PTEN inhibitor. Kaempferol improved the behavioral of CdCl2-treated rats, preserved hippocampus structure and reduced hippocampal levels of ROS and protein levels of Bax and cleaved caspase-3. In both control and CdCl2-treated rats, Kaempferol significantly increased hippocampal levels of GSH levels and protein levels of Nfr2, Bcl2 and synaptic proteins (SNAP-25, PSD-25, and synapsin). Concomitantly, it increased the activity of PTEN and AMPK and subsequently, decreased the activity of Akt and mTOR. In cultured cells, individual pharmacological inhibition of PTEN by bpv or AMPK of compound C (CC) partially prevented the stimulatory effect of Kaempferol on Akt/mTOR and its inhibitory effect on cell death whereas a combination of both inhibitors completely prevented this. Also, inhibition of PTEN alone completely abolished the inhibitory effect of Kaempferol by synaptic proteins, whereas inhibition of AMPK completely abolished its stimulatory effect of Nfr2. In conclusion, Kaempferol protects against CdCl2-induced memory deficits and hippocampal apoptosis by its antioxidant potential and inhibition of Akt/mTOR axis and requires the activation of PTEN and AMPK. [ABSTRACT FROM AUTHOR]

This study investigated the expression pattern, regulation of expression, and the role of hippocampal small-conductance Ca2+-activated K+ (SK) channels in memory deficits after cerebral hypoperfusion (CHP) with or without melatonin treatment, in rats. Adults male Wistar rats (n = 20/group) were divided into (1) a sham (2) a sham + melatonin (3) a two-vessel occlusion (2-VO) model, and (4) a 2-VO + melatonin. Melatonin was administered (i.p.) to all rats at a daily dose of 10 mg kg−1 for 7 days starting at the time of 2-VO-induction. In contrast to 2-VO rats, melatonin increased the latency of the passive avoidance learning test and decreased time to find the hidden platform in Water Morris Test in all tested rats. In addition, it concomitantly downregulated SK1, SK2, and SK3 channels, downregulated mRNA levels of TNFα and IL-1β, enhanced BDNF levels and activity of PKA levels, and restored the levels of cholinergic markers in the hippocampi of the treated-rats. Mechanistically, melatonin significantly prevented CHP-induced activation of ERK1/2, JNK, and P38 MAPK at least by inhibiting ROS generation and enhancing the total antioxidant potential. In cultured hypoxic hippocampal neurons, individual blockage of MAPK signaling by the MEK1/2 inhibitor (U0126), but not by the P38 inhibitor (SB203580) or JNK inhibitor (SP600125), completely prevented the upregulation of all three kinds of SK channels. These data clearly confirm that upregulation of SK channels plays a role in CHP-induced memory loss and indicate that melatonin reverses memory deficits after CHP in rats, at least by, downregulation of SK1, SK2, and SK3 channels in their hippocampi. [ABSTRACT FROM AUTHOR]

This study investigated if calcineurin/nuclear factor of activated T cells (NFAT) axis mediates the cardiac apoptosis in rats with type 1 diabetes mellitus (T1DM)-induced rats or administered chronically high-fat diet rich in corn oil (CO-HFD). Also, it investigated the impact of chronic administration of CO-HFD on Fas/Fas ligand (Fas/FasL)-induced apoptosis in the hearts of T1DM-induced rats. Adult male Wistar rats (140-160 g) were classified as control: (10% fat) CO-HFD: (40% fat), T1DM, and T1DM + CO-HFD (n=20/each). In vitro, cardiomyocytes were cultured in either low glucose (LG) or high glucose (HG) media in the presence or absence of linoleic acid (LA) and other inhibitors. Compared to the control, increased reactive oxygen species (ROS), protein levels of cytochrome C, cleaved caspase-8 and caspase-3, myocardial damage and impeded left ventricular (LV) function were observed in the hearts of all treated groups and maximally in T1DM + CO-HFD-treated rats. mRNA of all NFAT members (NFAT1-4) were not affected by any treatment. CO-HFD or LA significantly up-regulated Fas levels in both LVs and cultured cardiomyocytes in a ROS dependent mechanism and independent of modulating intracellular Ca2+ levels or calcineurin activity. T1DM or hyperglycemia significant up-regulated mRNA and protein levels of Fas and FasL by activating Ca2+/calcineurin/NFAT-4 axis. Furthermore, Fas/FasL cell death induced by recombinant FasL (rFasL) or HG media was enhanced by pre-incubating the cells with LA. In conclusion, activation of the Ca2+/calcineurin/NFAT4 axis is indispensable for hyperglycemia-induced Fas/FasL cell death in the cardiomyocytes and CO-HFD sensitizes this by up-regulation of Fas. [ABSTRACT FROM AUTHOR]

Context: Mechanisms by which ghrelin affords its cardioprotection in mammals remained unclear. Objective: To examine if ghrelin confers cardio-protection during cardiac remodelling post-MI by modulating the RAF-1-MEK1/2-ERK1/2 signalling pathway. Materials and methods: Rats were divided into control, sham, sham + ghrelin, myocardial infarction (MI), and MI + ghrelin groups. Ghrelin (100 µg/kg) was administered for 21 days, starting one-day post-MI. Results: Ghrelin enhanced cardiac contractility and the activities of antioxidant enzymes, lowered serum levels of enzyme markers of cardiac dysfunction, and lowered inflammatory mediator levels. Ghrelin increased levels of phospho-Raf-1 (Ser338), phospho-MEK1/2 (Ser217/221), phospho-ERK1/2 (Thr202/Tyr204), and of their downstream target p-BAD (Ser112) and inhibited the cleavage of caspase-3. Concomitantly, ghrelin prevented the increases in the levels of fibrotic markers, including α-smooth muscle actin (α-SMA), metalloproteinase-9 (MPP-9), and type III collagen. Conclusion: Post-MI in rats, ghrelin stimulated Raf-1-MEK1/2-ERK1/2-BAD signalling in the LV infarct areas, accounting for its anti-apoptotic effect, enhancing cardiac function, and inhibiting cardiac fibrosis during cardiac remodelling. [ABSTRACT FROM AUTHOR]

This study investigated the effect of ghrelin on cardiomyocytes function, apoptosis and ultra-structural alterations of remote myocardium of the left ventricle (LV) of rats, 21 days post myocardial infarction (MI). Rats were divided into 4 groups as a control, a sham-operated rats, a sham-operated+ghrelin, an MI + vehicle and an MI + ghrelin-treated rats. MI was induced by LAD ligation and then rats were recievd a concomitant doe of either normal saline as a vehicle or treated with ghrelin (100 μg/kg S.C., 2x/day) for 21 consecutive days. Ghrelin enhanced myocardial contractility in control rats and reversed the decreases in myocardial contractility and the increases in the serum levels of CK-MB and LDH in MI-induced rats. Additionally, it inhibited the increases in levels of Bax and cleaved caspase 3 and increased those for Bcl-2 in the remote myocardium of rat's LV, post-MI. At ultra-structural level, while ghrelin has no adverse effects on LV myocardium obtained from control or sham-treated rats, ghrelin post-administration to MI-induced rats reduced vascular formation, restored normal microfilaments appearance and organization, preserved mitochondria structure, and prevented mitochondrial swelling, collagen deposition and number of ghost bodies in the remote areas of their LV. Concomitantly, in remote myocardium of MI-induced rats, ghrelin enhanced endoplasmic reticulum intracellular organelles count, decreased number of atrophied nuclei and phagocytes, diminished the irregularity in the nuclear membranes and inhibited chromatin condensation. In conclusion, in addition to the physiological, biochemical and molecular evidence provided, this is the first study that confirms the anti-apoptotic effect of ghrelin in the remote myocardium of the LV during late MI at the level of ultra-structural changes. [ABSTRACT FROM AUTHOR]

Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12% of calories as fat); Group II: fed HFD (40% of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8% decrease in sperm count, 44.72% decrease in sperm motility, as well as 47.09% increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8% (P=0.0012) and 45.6±4.6% (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9%, P≤0.0001). Finally, endurance exercise training and Orlistat administration in dividually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat testes, diet induced obesity down regulates SCF expression, upregulates Ghrelin expression, and deteriorate oxidative stress levels, which are collectively detrimental to semen parameters. Exercise, and to a lesser extent Orlistat administration, protected effectively against this detrimental effect. [ABSTRACT FROM AUTHOR]

This study compared the effect of low‐fat diet (LFD) and high‐fat diet rich in corn oil (HFD‐CO) on left ventricular (LV) fibrosis in rats and examined their effect of angiotensin II (ANG II), JAK/STAT, and TGF‐1β/smad3 pathways. As compared to LFD which didn't affect any of the measured parameters, HFD‐CO‐induced type 2 diabetes phenotype and increased LV collagen synthesis. Mechanistically, it increased LV levels of ROS, ANG II, ACE, IL‐6, s‐IL‐6Rα, TGF‐β1, Smad‐3, and activities of JAK1/2 and STAT1/3. AG490, a JAK2 inhibitor, partially ameliorated these effect while Losartan, an AT1 inhibitor completely abolished collagen synthesis. However, with both treatments, levels of ANG II, IL‐6, and s‐IL‐6Rα, and activity of JAK1/STAT3 remained high, all of which were normalized by co‐administration of NAC or IL‐6 neutralizing antibody. In conclusion: HFD‐CO enhances LV collage synthesis by activation of JAK1/STAT3/ANG II/TGF‐1β/smad3 pathway. Practical applications: We report that chronic consumption of a high‐fat diet rich in corn oil (HFD‐CO) induces diabetes mellitus phenotype 2 associated with left ventricular (LV) cardiac fibrosis in rats. The findings of this study show that HFD‐CO, and through the increasing generation of ROS and IL‐6 levels and shedding, could activate LV JAK1/2‐STAT1/3  and  renin‐angiotensin system (RAS) signaling pathways, thus creating a positive feedback between the two which ultimately leads to activation of TGF‐1β/Smad3 fibrotic pathway. Herein, we also report a beneficial effect of the antioxidant, NAC, or IL‐6 neutralizing antibody in preventing such adverse effects of such HFD‐CO. However, this presents a warning message to the current sudden increase in idiopathic cardiac disorders, especially with the big shift in our diets toward n‐6 PUFA. [ABSTRACT FROM AUTHOR]