肠缺血/再灌注损伤对leptin及orexin-A水平的影响

Effect of intestinal ischemia/reperfusion injury on leptin and orexin-A levels

目的研究肠缺血/再灌注(I/R)损伤对外周血及中枢分泌组织leptin及orexin-A水平的影响,探讨leptin及orexin-A在急性炎症反应中的作用。方法建立大鼠肠I/R损伤模型,设立缺血60min后不同时间的再灌注损伤组。采用放射免疫分析法测量血清及脂肪组织leptin、血浆及下丘脑orexin-A蛋白水平的变化,并用逆转录-聚合酶链式反应法检测脂肪组织leptin、下丘脑orexin-AmRNA表达水平的变化。结果与损伤前自身对照相比,缺血60min/再灌注30min组(I60'R30')血清leptin显著降低,I60'R360'组显著增高。与损伤后假手术组(sham)相比,I60'R360'组血清Leptin水平显著增高。与损伤后sham组相比,I60'R30'、I60'R90'组脂肪leptin蛋白水平显著降低,I60'R360'组显著增高。与损伤后Sham组相比,I60'R30'、I60'R240'、I60'R360'组脂肪leptinmRNA表达显著增高,I60'R150'组显著降低。各组损伤前、后的血浆及下丘脑orexin-A蛋白水平无显著性差异。与损伤后sham组相比,I60'R30'、I60'R90'组下丘脑orexin-AmRNA表达逐步降低,I60'R150'组最低,I60'R240'、I60'R360'组逐步回升但仍低于sham组。结论Leptin及orexin-A对肠I/R损伤的应答具有时间依赖效应,leptin比orexin-A的应答较迅速,两者可能在急性炎症反应的能量代谢障碍中发挥一定的作用。

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 hypothalarnns 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 alter 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 eider in the plasma or hypothalamns 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 lime-dependent response to intestinal I/R injury, but the former appears to exhibit a roster response, and they may play a certainrole in the metabolic disorders of acute inflammation.