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Objective: To study the effect of leptin on neuron apoptosis in mice with cerebral ischemia injury., Methods: Seventy-five male Kuming mice were randomly divided into 3 groups:sham, model and leptin intervention group, respectively. Focal cerebral ischemia/reperfusion injury model in mice was established by middle cerebral artery occlusion. Leptin intervention group was injected with leptin (1 μ g/g weight, I. P.) at 0 min of ischemic injury. Neuron apoptosis was detected by TUNEL staining. The mRNA expression of apoptosis relative gene bcl-2 and caspase-3 were detected by RT-PCR. The protein expression of bcl-2 and caspase-3 were detected by immunohistochemistry., Results: In model group, most of the neurons in the central area of cerebral ischemia had necrosis obviously, and the amount of neuron apop-tosis was much higher than that in sham group ( P <0.01). Compared with sham group, both expression of pro-apoptosis gene caspase-3 and anti-apoptosis gene bcl-2 increased significantly in model group ( P <0.01). Compared with model group, the amount of neuron apoptosis and expression level of caspase-3 were decreased significantly ( P <0.01), whereas the mRNA and protein expression of bcl-2 were increased sig-nificantly in leptin intervention group ( P <0.01)., Conclusions: Leptin could reduce neuron apoptosis through down-regulation the expression of caspase-3 and up-regulation the expression of bcl-2. It suggests that leptin could play a neuroprotective role in cerebral ischemia injury.

Objective: To explore the effect of repeated hypoxic preconditioning (RHP) on renal ischemia-reperfusion-induced hepatic dysfunction in rats and the underlying mechanism., Methods: A total of 120 normal SD rats were randomly divided into 4 groups (n=40), namely RHP surgical group, RHP sham-operated (RHPS) group, nonhypoxic surgical group (IRI group), and nonhypoxic sham-operated group (S group). The rats in the hypoxic groups were exposed to hypoxia in a hypoxic chamber for 5 days prior to establishment of renal ischemia-reperfusion model by resection of the right kidney and clamping the left renal hilum. Serum alanine aminotransferase (ALT), IL-17 A, TNF-a, liver superoxide dismutase (SOD) and nitric oxide (NO) were detected at 2, 8 and 24h after reperfusion, and Western blotting was used to determine the expression of p-PI3K and p-AKT;HE staining was used to observe the structural changes in the liver., Results: Compared with IRI group, RHP group showed significantly milder hepatic damage, lower ALT levels and higher NO levels at 2, 8, and 24 after reperfusion (P<0.05); TNF-a levels were lowered at 24 h (P<0.05) and SOD increased at 8 h after the reperfusion (P<0.05). Compared with S group, IRI group and RHP group showed significantly higher IL-17A levels (P<0.05) but without significant difference between the latter two groups (P>0.05). The expressions of p-PI3K and P-Al

Background: Previous studies have demonstrated that both curcumin and leptin are protective factors against acute injuries. Here, we investigated whether leptin and its signaling pathway mediate the protective effects of curcumin., Methods: A solid dispersion of curcumin-polyvinylpyrrolidone K30 was prepared and administered intraperitoneally. In vivo intestinal ischemia/reperfusion (I/R) injury in mice determined the effects of curcumin administration on inflammation, oxygen radical production, and leptin expression. In vitro studies using the venous epithelial cell line ECV-304 examined hypoxia/reoxygenation-induced leptin expression and release after curcumin administration. Furthermore, the effects on the leptin-regulated ERK1/2 and p38 MAPK signaling pathways were also explored., Results: Intestinal I/R induced marked bowel injuries. Curcumin treatment significantly improved animal survival and reduced the pathologic injuries in the intestines. Furthermore, the elevated intestinal water content and levels of malondialdehyde, interleukin 1β (IL-1β) and IL-6 were significantly decreased, but levels of superoxide dismutase increased. Interestingly, we found that the decreased leptin and its receptor Ob-Rb were restored by curcumin administration. In addition, in vitro studies showed that curcumin increased leptin expression and release after hypoxia/reoxygenation-induced cell injuries. Moreover, curcumin treatment restored decreased ERK1/2 phosphorylation (p-ERK1/2) and inhibited overactive p38 (p-p38) after injuries, and the effect was reversed by a leptin-specific antibody or Ob-R blocker., Conclusion: These data suggest that leptin and Ob-Rb-dependent ERK and p38 MAPK signaling pathways may be involved in curcumin protection against intestinal I/R injury, and leptin may be a potential target of curcumin in intestinal I/R injury and other related acute diseases.

Objective: To explore the effect of leptin on expression of Cx43 after rat cerebral ischemia/ reperfusion injury and its related mechanism., Methods: Forty-five male kunming mice were randomly divided into 3 groups: sham group, model group and leptin group. Mouse models of transient focal cerebral ischemia were established by occlusion of the right middle cerebral artery for 2 h followed by 24 h reperfusion in model and leptin group. Mice of leptin group were intraperitoneally injected with 1 mg/kg leptin at 0 minute after ischemia. The infarct volume and neurological deficit scores following leptin treatment were determined using TTC staining and the Longa's score, respectively, to evaluate the protective effect of leptin against ischemic cerebral injury. The histopathological changes in the brain were observed with HE staining. The astrocytes of SD rat cerebral cotex were cultured primaryly and purified, and then divided them into four groups: control, model, leptin 100 microg/L, and leptin 500 microg/L. The cerebral astrocytes with hypoxia/reoxygenation injury were induced. The cellular viability of injury was detected by MTT assay. The effect of leptin on Cx43 expression was detected by Western blot in brain tissues and astrocytes., Results: Compared with the model group, the neurological deficits and cerebral infarct volume of leptin group were reduced (P< 0.05), the histopathological injury in the brain tissues was alleviated and the expression of Cx43 was decreased markedly (P < 0.01). The survival rate of astrocytes was increased significantly in leptin 500 microg/L group (P < 0.01), whereas the Cx43 expression of astrocytes decreased (P < 0.01). But the difference of leptin 100 mcirog/L was not significant (P > 0.05)., Conclusion: Leptin can ameliorate cerebral pathological changes in the event of IR injury by suppressing the expression of Cx43 both in vivo and vitro experiments.

Background: Recently, research has indicated that leptin plays a protective role in traumatic brain and liver injury. We studied the protective effect of leptin on intestinal I/R injury and examined its mechanism by using mice intestinal I/R model and murine peritoneal macrophage hypoxia/reoxygenation (H/R) injury model., Methods: Leptin was intraperitoneally administrated at 45 minutes after ischemia, then reperfusion for two hours. Cells were treated with different concentrations of leptin at three hours after hypoxia, then reoxygenation for six hours. Mice intestines were harvested for histopathologic properties. The malondialdehyde, nitric oxide (NO), interleukin-6, and total antioxidative capacity were detected according to respective assay kit. Phosphorylated extracellular regulated kinase1/2 (p-ERK1/2) and phosphorylated cytosolic phospholipase A(2) (p-cPLA2) were determined by Western blot assay., Results: Here, we show that leptin reduced intestinal histologic alterations, malondialdehyde and interleukin-6 levels but increased the endogenous leptin expression and NO production in the intestines. Leptin also increased the NO and total antioxidative capacity levels in cells. We further demonstrated that leptin markedly activated ERK1/2 in the intestines and activated ERK1/2 and cPLA2 in the cells. Moreover, the protective effect of leptin against intestinal I/R injury and elevated NO production was attenuated by blocking the ERK1/2 pathway., Conclusions: These data demonstrate that leptin ameliorated intestinal I/R and peritoneal macrophage H/R injury by enhancing ERK1/2 phosphorylation and promoting the NO production signaling pathway.

Ischemic stroke is a medical emergency triggered by a rapid reduction in blood supply to localized portions of the brain, usually because of thrombosis or embolism, which leads to neuronal dysfunction and death in the affected brain areas. Leptin is generally considered to be a strong and quick stress mediator after injuries. However, whether and how peripherally administered leptin performs neuroprotective potency in cerebral stroke has not been fully investigated. It has been reported that CGRP(8-37), an antagonist of the CGRP receptor, could reverse the protective effect of leptin on rats with CIP (caerulein-induced pancreatitis). However, the question remains: are leptin and CGRP associated in cerebral ischemia/reperfusion injury? The present study attempted to evaluate the relationship between CGRP expression and leptin neuroprotective effects (1mg/kg in 200 μL normal saline, i.p.) on focal cerebral ischemia/reperfusion injury in mice and the protective effect of leptin (500 μg/L) on neurons during hypoxia/reoxygenation injury. Peripheral administration of leptin alleviated injury-evoked brain damage by promoting CGRP expression, improving regional cerebral blood flow, and reducing local infarct volume and neurological deficits. Furthermore, leptin also promoted bcl-2 expression and suppressed caspase-3 in vivo and vitro after injury. Administration of CGRP(8-37) (4 × 10(-8)mol/L) partly abolished the beneficial effects of leptin, and restored the normal expression levels of bcl-2 and caspase-3 in neurons, which indicated that leptin-induced protection of neurons was correlated with release of CGRP. These results indicate that the neuroprotective effect of leptin against cerebral ischemia/reperfusion injury may be strongly relevant to the increase of CGRP expression., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Objective: To study the effect of Leptin on neuron apoptosis in mice with cerebral ischemia injury and its mechanism., Methods: Seventy-five mice were randomly divided into three groups. Focal cerebral ischemia/reperfusion injury model in mice was reproduced by middle cerebral artery occlusion for 2 hours followed by reperfusion. In Leptin intervention group mice were given Leptin 1 μg/g during cerebral ischemia by intraperitoneal injection. Mice in the model group were given equal amount of phosphate buffer saline. After reperfusion for 24 hours, the neuron apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. The mRNA and protein expression of apoptosis relative gene caspase-3 and bcl-2 were determined by reverse transcription-polymerase chain reaction (RT-PCR) and immuno histochemistry., Results: Most of neuron necrosis was observed in cerebral ischemia center in model group. Compared with sham-operation group, neuron apoptosis rate, mRNA and protein expression of caspase-3 and bcl-2 in model group increased significantly [apoptosis rate: (68.65 ± 0.79)% vs. (4.40 ± 0.00)%, caspase-3 mRNA: 2.563 ± 0.250 vs. 0.153 ± 0.020, bcl-2 mRNA: 0.337 ± 0.100 vs. 0.125 ± 0.030, caspase-3 protein (absorbance value, A value): 0.57 ± 0.05 vs. 0.37 ± 0.03, bcl-2 protein (A value): 0.51 ± 0.04 vs. 0.35 ± 0.01, all P<0.01]. The apoptosis rate of penumbra neurons was reduced in Leptin intervention group significantly compared with model group [(42.30 ± 8.45)% vs. (68.65 ± 0.79)%, P<0.01]. Compared with model group, the mRNA and protein expression of caspase-3 in Leptin intervention group were reduced significantly [caspase-3 mRNA: 2.267 ± 0.040 vs. 2.563 ± 0.250, caspase-3 protein (A value): 0.45 ± 0.04 vs. 0.57 ± 0.05, P>0.05 and P<0.01], and the mRNA and protein expression of bcl-2 in Leptin intervention group upregulated significantly [bcl-2 mRNA: 0.662 ± 0.040 vs. 0.337 ± 0.100, bcl-2 protein (A value): 0.76 ± 0.09 vs. 0.51 ± 0.04, both P<0.01]., Conclusion: Leptin could reduce apoptosis of neurons through down-regulation of the expression of caspase-3 and up-regulation of the expression of bcl-2. The results suggest that Leptin plays a neuroprotective role in cerebral ischemia injury.

Aim: To evaluate the role of leptin in the internal disorders during hepatic ischemia/reperfusion injury., Methods: A rat model of 70% hepatic ischemia/reperfusion injury was established, with groups of sham-operation (Sham), 60 min ischemia/60 min reperfusion (I60'R60'), I60'R150', I60'R240' and I60'R360'. Serum leptin was detected by a self-produced radioimmunoassay; serum glucose, total anti-oxidation capacity, myeloperoxidase, alanine transaminase and diamine oxidase were determined by relevant kits, while histological alterations and protein levels of leptin in the lung, liver and duodenum were examined by hematoxylin-eosin staining and immunohistochemistry. Spearman's rank correlation between leptin and other variables or grading of tissue impairment were analyzed simultaneously., Results: Serum leptin in I60'R360' was significantly higher than in Sham and I60'R240' groups (both P < 0.05), serum glucose in I60'R360' was higher than in Sham and I60'R150' (both P < 0.05), and serum total anti-oxidation capacity in I60'R240' and I60'R360' were higher than in Sham (both P < 0.05) and I60'R150'groups (both P < 0.01). Serum myeloperoxidase in groups of I60'R240' and I60'R360' were lower than in I60'R150'group (both P < 0.05), serum alanine transaminase in the four reperfusion groups were higher than in the Sham group (all P < 0.05), while serum DAO in I60'R360' was lower than in I60'R60' (P < 0.05). Histological impairment in the lung, liver and duodenum at the early phase of this injury was more serious, but the impairment at the later phase was lessened gradually. Protein levels of leptin in the lung in the four reperfusion groups were significantly lower than in the Sham group (all P < 0.01), decreasing in the order of I60'R150', I60'R60', I60'R360' and I60'R240'; the levels in the liver in I60'R60' and I60'R240' were higher than in the Sham group (both P < 0.01), while the levels in I60'R240' and I60'R360' were lower than in I60'R60' (both P < 0.01); the levels in duodenum in I60'R240' and I60'R360' were higher than in Sham, I60'R60' and I60'R150' (all P < 0.01), while the level in I60'R150' was lower than in I60'R60' (P < 0.05). There was a significantly positive correlation between serum leptin and alanine transaminase (ρ = 0.344, P = 0.021), a significantly negative correlation between the protein level of leptin in the lung and its damage scores (ρ = -0.313, P = 0.036), and a significantly positive correlation between the protein level of leptin in the liver and its damage scores (ρ = 0.297, P = 0.047)., Conclusion: Endogenous leptin fluctuates in hepatic ischemia/reperfusion injury, exerts a potency to rehabilitate the internal disorders and represents a potential target for supportive therapy.

Objective: To investigate the effect of leptin on apoptosis of rat cerebral astrocytes with ischemia/ hypoxia injury and its mechanism., Methods: The cerebral astrocytes with ischemic/hypoxia injury were induced in neonatal SD rats. The cellular viability of injury of astrocytes was detected by MTT assay. The apoptosis of astrocyte were detected with Annexin V-FITC kit. The effect of leptin on the expression of apoptosis factor bcl-2, bax, caspase-3 was detected by RT-PCR and Western blot., Results: Compared with the ischemia group, the cellular viability of leptin intervention group increased significantly (P < 0.01), while the astrocytes apoptosis of leptin intervention group decreased significantly (P < 0.01). The mRNA and protein expression level of antiapoptosis factor bcl-2 in leptin intervention group was much higher than that of ischemia group (P < 0.01), whereas the mRNA and protein expression of bax and caspase-3 was much lower than that of ischemia group (P < 0.01)., Conclusion: Leptin could significantly decrease the apoptosis of astrocytes with ischemia/hypoxia injury, and it i relevant to the increase of bcl-2 expression and the decrease of bax caspase-3 expression level.

Unlabelled: OBJECTIVE; To study the changes of leptin after hepatic ischemia/reperfusion (H-I/R) and its effects on H-I/R-induced hepatic injury., Methods: A 70% H-I/R model of rats was established. The rats were divided into groups with different reperfusion times and sham-operation group. Radioimmunoassay was applied to measure protein levels of leptin in serum and adipose tissues of the rats. Enzyme-colorimetry was used to detect serum alanine transaminase. Hematoxylin-eosin staining and immunohistochemistry were applied to investigate pathological variations and protein expressions of leptin in livers, respectively. RT-PCR was used to detect leptin mRNA expressions in adipose tissues and livers., Results: Compared with the sham-operation group, serum leptin increased significantly in the 60 min ischemia/360 min reperfusion (I60' R360') group; protein level of leptin in adipose tissues increased significantly in the I60'R60' group; serum alanine transaminase increased significantly in all of the four reperfusion groups; protein expressions of leptin in livers increased significantly in the I60'R60' and 160'R240' groups; leptin mRNA expression in adipose tissues decreased significantly in the I60'R150' group; leptin mRNA expression in livers increased significantly in the 160'R60' group; leptin mRNA expressions in livers decreased significantly in the I60'R150', I60'R240' and I60'R360' groups. Pathological investigation showed that hepatic impairments at the early phase of H-I/R were more serious. The impairments at the later phase lessened gradually., Conclusion: The change of leptin expressions after H-I/R may be a protective factor to withstand H-I/ R-induced hepatic injury.

Objective: To investigate the protective effect of leptin against cerebral ischemia/reperfusion injury in mice., Methods: Mouse models of transient focal cerebral ischemia were established by occlusion of the right middle cerebral artery for 2 h followed by 24 h reperfusion. The infarct volume and neurological deficit scores following leptin treatment were determined using TTC staining and the Longa's score, respectively, to evaluate the protective effect of leptin against ischemic cerebral injury. The levels of lactate dehydrogenase (LDH), malondialdehyde (MDA) and nitric oxide (NO) in the brain tissue were measured by colorimetry. The histopathological changes in the brain were observed with HE staining, and the expression of glial fibrillary acidicprotein (GFAP) was detected by immunohistochemistry., Results: Leptin treatment markedly reduced cerebral infarct volume and neurological deficits induced by transient ischemia. The LDH, MDA and NO levels in the brain tissues were significantly decreased after leptin treatment, which also alleviated the histopathological injury, maintained the normal morphology of the astrocytes and increased the expression of GFAP., Conclusion: Leptin produces obvious protective effect against cerebral ischemia/reperfusion injury by inhibiting lipid peroxidation, stabilizing the internal environment and adjusting the activity of the astrocytes.

Objective: To investigate the effect of intestinal ischemia/reperfusion (I/R) injury on orexin-A levels in plasma and hypothalamus, and to find out the role of orexin-A in acute inflammatory responses., Methods: Fifty-four SD rats were randomly divided into a sham-operation group and 5 experiment groups. Then we established the intestinal I/R injury model of rats and setup the 5 experiment groups of 60 min ischemia followed by different periods of time for reperfusion. Protein levels of orexin-A in plasma and hypothalamus were measured by radioimmunoassay, and the changes of orexin-A mRNA expression in hypothalamus were detected by RT-PCR., Results: By analyses on the orexin-A levels in plasma of rats before and after injury, no significant change was observed in the 5 experiment groups (P > 0.05), and the 5 groups' post-injury orexin-A levels in plasma and hypothalamus were not significantly different from the sham-operation group's (P > 0.05). However, by comparison with the sham-operation group after injury, the experiment groups were found to have orexin-A mRNA levels in hypothalamus significantly decreased step by step from 60 min ishchemia/30 min reperfusion (160' R30') to 160'R150'; the lowest level was seen at 160'R150'; and at 160'R240' and I60'R360', the level recovered slowly, but it was still lower than that seen in the sham-operation group., Conclusion: Orexin-A makes a delayed response to intestinal I/R injury and may function as inflammatory cytokine in the metabolic disorders caused by acute inflammation.

Objective: To explore the effect of intestinal ischemia/reperfusion (I/R) injury on leptin and orexin-A levels in peripheral blood and central secretory tissues, and investigate the roles of leptin and orexin-A in acute inflammatory responses., Methods: An intestinal I/R injury rat model was established, and the rats were grouped according to duration of the reperfusion time following a 60-min ischemia. Radioimmunoassay was used to examine the protein levels of leptin in the serum and adipose tissue, and the protein levels of orexin-A in the plasma and hypothalamus. Reverse transcriptase-polymerase chain reaction was also performed to detect the mRNA expressions of adipose leptin and hypothalamus orexin-A., Results: Compared with that before injury, serum leptin level of 60-min ischemia with 30-min reperfusion (I60'R30') group decreased significantly and that of I60'R360' increased significantly. Compared with the sham-operation group (sham) after injury, serum leptin level of I60'R360' group increased significantly, and adipose leptin protein levels of I60'R30' and I60'R90' groups decreased significantly, whereas that of I60'R360' group increased obviously. Compared with sham group after injury, adipose leptin mRNA expressions of I60'R30', I60'R240' and I60'R360' groups all increased significantly, while that of I60'R150' showed significant decrease. No significant changes were noted in the protein levels of orexin-A either in the plasma or hypothalamus after I/R injury. In comparison with sham group after injury, hypothalamus orexin-A mRNA expressions of I60'R30' and I60'R90' groups showed gradual but significant decrease, and till 150 min of reperfusion, the expression reached its lowest, followed then by slow recovery at 240 and 360 min, though still remaining significantly lower than that of sham group., Conclusion: Leptin and orexin-A have a time-dependent response to intestinal I/R injury, but the former appears to exhibit a faster response, and they may play a certain role in the metabolic disorders of acute inflammation.

To explore the role and the rule of leptin levels in severe traumatism, an ischemia-reperfusion injury model was established to observe change of leptin levels, and platelet activating factor, noradrenaline, lipopolysaccharide, and endothelin-1 were utilized to induce vascular endothelial cells. Leptin concentrations in serum and supernatant were detected by murine and human leptin radioimmunoassay. The results showed that the first serum leptin level significantly decreased after an injury of 60 min ischemia and 30 min reperfusion versus pre-experimental serum values, and leptin level in serum showed a variational trend to increase as reperfusion time extended; the second, supernatant leptin level significantly decreased after PAF and ET-1 treatments of 6 and 24 h versus the control group. It can be concluded that leptin maybe an inflammatory cytokine to play a protection role in acute inflammation and traumatism.

Objective: To explore the distribution of Orexin-A mRNA expression in different organs, and its variation in acute inflammation, and to evaluate the role of Orexin-A in acute inflammatory responses., Methods: Hypothalamus, adipose tissue, lung, stomach, duodenum, liver, spleen and testis of male Sprague-Dawley rats (including normal and those of intestinal ischemia/reperfusion injury model) were harvested, and reverse transcription-polymerase chain reaction(RT-PCR) was used to assess Orexin-A mRNA expression in different tissues of normal rats, and that in the hypothalamus of ischemia/reperfusion injured rats., Results: All tissues expressed Orexin-A mRNA, and it was especially high in the stomach, lung and kidney. After the acute stimulus of ischemia/reperfusion injury, Orexin-A mRNA expression showed a trend of fluctuant declination in the hypothalamus., Conclusion: Orexin-A mRNA is widely expressed in the major organs, and it has a time-dependent response to acute inflammatory stimuli. The results suggest that its expression variation may be used as a novel marker for acute inflammation.

Aim: To explore the effect of intestinal ischemia-reperfusion injury on protein levels of leptin and orexin-A in peripheral blood and their central secretory tissues and to find out the role leptin and orexin-A play in acute inflammatory responses., Methods: An intestinal ischemia-reperfusion (I/R) injury model of rats was established and rats were divided randomly into six groups: sham-operation group, 60 min ischemia/30 min reperfusion group (I60'R30'), I60'R90', I60'R150', I60'R240' and I60'R360', 9 rats each group. Two highly-sensitive radioimmunoassays for leptin and orexin-A were established and used to check the change of their concentrations in peripheral blood and central secretory tissues before and after intestinal I/R injury., Results: Compared with the serum leptin level before injury, it decreased significantly in I60'R30' group and increased significantly in I60'R360' group; compared to sham-operation group after injury, serum leptin level increased significantly in I60'R360' group; compared to sham-operation group after injury, adipose leptin levels decreased significantly in I60'R30' and I60'R90' groups, while increased significantly in I60'R360' group. There was no significant difference between the expression levels of orexin-A before and after I/R injury., Conclusion: Leptin has a time-dependent response and orexin-A has a delayed response to acute inflammatory stimuli such as intestinal I/R injury and they may participate in metabolic disorders in injury as inflammatory cytokines.

As leptin is an active mediator mainly secreted by adipose tissue and is closely related with energy metabolism, we evaluate both the changes of leptin levels in serum and adipose tissue with a concise radioimmunoassay and the changes of leptin mRNA expression in adipose tissue with RT-PCR, during the severe metabolic impediment in rat intestinal ischemia-reperfusion (I/R) injury. Results show that not only leptin levels in serum and adipose tissue but also its mRNA expression in adipose tissue undergo a fluctuation according to different injury times. Therefore, we conclude that leptin has a time-dependent response to acute inflammatory stimuli and acts as an anti-inflammatory cytokine.

Objective: To investigate the effect of intestinal ischemia/reperfusion injury on Leptin levels in serum and adipose tissue, and evaluate the potential role of Leptin in acute inflammatory response., Methods: An intestinal ischemia/reperfusion injury model of rats was reproduced. Serum and adipose tissue Leptin concentrations and Leptin mRNA expression in adipose tissue were determined by a highly-sensitive murine Leptin radioimmunoassay and reverse transcription-polymerase chain reaction (RT-PCR), respectively., Results: Compared with animals prior to injury, serum Leptin level decreased significantly in ischemia for 60 minutes followed by reperfusion for 30 minutes (I60R30), but it tended to increase in I60R150 and significantly increased in I60R360. Compared with sham group, serum Leptin level tended to increase in I60R240 and elevated significantly in I60R360; Leptin levels in adipose tissue significantly decreased in I60R30 and I60R90, while they increased significantly in I60R360. Compared with sham group, Leptin mRNA levels elevated significantly in I60R30, I60R240 and I60R360, but lowered significantly in I60R150., Conclusion: Leptin has a time-dependent response to acute inflammatory stimuli such as intestinal ischemia/reperfusion injury, and it migh play a role as an inflammatory cytokine.

Objective: To explore the effect of intestinal ischemia/reperfusion injury on Leptin concentrations in serum and adipose tissue, and to find out the role of Leptin in acute inflammatory responses., Methods: An intestinal ischemia-reperfusion injury model of rats was established, and used a highly-sensitive murine Leptin radioimmunoassay to check the change of Leptin concentrations in serum and adipose tissue., Results: Serum Leptin level (10.82+/-0.83) microg/L significantly decreased after an injury of 60-minute ischemia and 30-minute reperfusion versus pre-experimental serum levels (16.46+/-3.21) microg/L; Leptin level in serum was higher than that in adipose tissue (4.466+/-2.63) mg/100g, and they both showed a similar changeable trend to increase step by step as reperfusion time extended (P=0.047)., Conclusion: Leptin may be an inflammatory cytokine and may play a role in inflammatory responses such as intestinal ischemia/reperfusion.

The experiments were carried out to explore the interactions between IL-1 beta gene expression, protein level and phospholipase A(2) PLA(2) inhibition after intestinal ischemia/reperfusion injury. Using a rat intestinal ischemia/reperfusion injury model, after collecting the serum, lung lavage, abdomen cavity lavage and important organ tissue samples from control, injury and PLA(2) inhibitor treated groups, IL-1 beta level was measured by radioimmunoassay, and the mRNA expression of IL-1 beta and type II PLA (2)was determined by RT-PCR. After 6 h of injury, the IL-1 beta level in serum was significantly higher than that in the control group; an increase in IL-1 beta was also observed in abdomen cavity lavage 1 or 3 h after injury. IL-1 beta was significantly increased in liver tissue after injury, but was not changed obviously in the lung, kidney and intestinal tissues. IL-1 beta in the lung lavage was significantly higher than that of control group. The mRNA expression of IL-1 beta in lung tissue was increased after injury, but type II PLA(2) mRNA expression was decreased. There were different changes in IL-1 beta level and gene expression after treatment with PLA(2) inhibitor chloroquine, cyclo-oxidase inhibitor indomethacin, or PAF receptor antagonist SR27417 respectively after injury. All these results indicate that after intestinal ischemia/reperfusion injury, the IL-1 beta level and mRNA gene expression are significantly increased, however, the relationship among IL-1 beta, PLA(2) activation and its metabolite release remains to be further elucidated.