肢体缺血后处理和肾脏缺血后处理对大鼠肾脏缺血-再灌注损伤的影响

摘要

Objective To investigate the effects of limb or renal ischemia postconditionings (IPC)on renal ischemia-reperfusion(I-R)injury in rats.Methods Twenty-four rats were randomly divided into four groups of I-R,the left hind limb IPC(LIP),renal IPC(RIP)and shanl operation(S)with 6 rats each.The renal I-R model was established by clamping of the left renal artery for 45 minutes followed by 6 hours reperfusion.The fight kidneys were removed just after the beginning of the reperfusion of left kidneys.The rats in group S subjected to the same surgical procedure without clamping the left renal artery.One minute before the reperfusion following 45 minutes ischemia in the left kidney,the left femoral arteries of group RIP had been clipped for 5 minutes.:Kidneys of group IPC were subjected to six cycles of 10 seconds of reperfusion followed bv 10 seconds ischemia immediately after 45 min of ischemia The rats were killed at 6 h of reperfusion,and blood samples were collected from right atrium for the measurements of serum ereatinine(Cr)and blood urea nitrogen (BUN).The renal expressions of Fas and Caspase-3 were detected by immunohistochemistry and the apoptotic cells were exarned by TUNEL method.Pathological changes of renal tissues were observed under light microscope and electron microscopy.The apoptotic cells in tubular epithelial cell were calculated for apoptosis index(AI).Results Compared to group S,BUN and SCr of other three groups were significantly increased with marked pathologic changes and the increases in the expressions of Caspase-3 and Fas in kidney cells(P<0.01).Compared with group I-R,BUN and SCr of groups of LIP and RIP were decreased with the decreases in the expressions of Fas and Caspase-3 and apoptosis(P<0.01).The apoptosis was less in group RIP than that in group LIP[(2.03±0.09)vs.(2.39±0.03)(P<0.05).Conclusion The apoptosis of tubular epithelial cells occure by activating Fas in the pathological process of I-R injury.Both of the ischemic postconditionings can inhibit the apoptosis in tubular epithelial cells and attenuate the I-R injury.%目的 探讨肢体缺血后处理和肾脏缺血后处理对大鼠肾脏缺血-再灌注(I-R)损伤的影响.方法 24只大鼠随机均分为假手术组(S组)、缺血-再灌注组(I-R组)、左下肢缺血后处理组(LIP组)及肾脏缺血后处理组(RIP组).S组仅对左肾动脉进行游离;I-R组:夹闭左肾动脉45 min后松开,左肾再灌注6 h;LIP组在左肾复灌前6 min时左股动脉夹闭5 min;RIP组在左肾缺血45min后灌注10 s,停灌10 s,反复6次;检测复灌6 h时血清肌酐(Cr)、血尿素氮(BUN);光镜下观察肾组织病理改变,TUNEL法检测肾组织中凋亡细胞并计算凋亡指数(AI);免疫组化法检测肾组织Fas、Caspase-3表达;电镜下观察肾单位超微结构改变.结果 与S组比较,其他三组大鼠BUN、Cr浓度升高(P<0.01)、肾组织病理改变明显、肾组织Fas、Caspase-3阳性指数和AI增加(P<0.01).与I-R组比较,LIP、RIP组大鼠BUN、Cr浓度降低(P<0.01),肾组织Fas、Caspase-3阳性指数和AI降低(P<0.01).RIP组AI明显低于LIP组(P<0.05).结论 在肾脏I-R损伤的病理过程中,肾小管上皮细胞凋亡可以由胞膜上的Fas被激活而最终导致靶细胞凋亡;两种后处理都可以抑制肾小管上皮细胞凋亡,减轻I-R损伤.