Effect of intestinal ischemia-reperfusion injury on protein levels of leptin and orexin-A in peripheral blood and central secretory tissues

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. (C) 2005 The WJG Press and Elsevier Inc. All rights reserved.