肢体缺血预处理对大鼠肝缺血-再灌注损伤的延迟性保护作用

Delayed protective effects of limb ischemic preconditioning on liver ischemia-reperfusion injury in rats

目的观察肢体缺血预处理(LIPC)对大鼠肝缺血-再灌注(I-R)损伤的延迟性保护作用。方法雄性SD大鼠36只,随机分为对照组(S组),I-R组,LIPC组,每组12只。S组仅行开腹,不作其他处理;I-R组行肝缺血1h,再灌注3h;LIPC组先行双后肢缺血5min,反复3次24h后行肝缺血1h,再灌注3h。手术完毕,腹主动脉采血用于检测总超氧化物歧化酶(T-SOD)、丙二醛(MDA)、血清ALT与AST;切取肝组织,测定肝脏的湿干比(W/D),免疫组化检测肿瘤坏死因子α(TNF-α)的表达,同时光电镜观察肝组织显微、超微结构的变化。结果与I-R组比较,LIPC组T-SOD活性增加(P<0.01),MDA水平、ALT、AST、W/D值及TNF-α的阳性表达均明显降低(P<0.01),肝脏的显微及超微结构损伤减轻。结论 LIPC对大鼠肝脏I-R损伤有明显的延迟性保护作用。其机制可能与增加机体抗氧化能力、抑制肝脏炎症反应、减轻肝脏水肿、抑制TNF-α的表达和改善肝组织微循环有关。

Objective To study the delayed protective effects of limb ischemia preconditioning （LIP（2） on liver ischemia-reperfusion（I-R） injury in rats. Methods Thirty-six SD rats were equally randomized into there groups of S（sham operated）, I-R（I-R model） and LIPC （LIPC before I-R）. I-R model was established by 70% liver ischemia for 1 hour and reperfusion for 3 hours. LIPC was performed by 5-min ischemia of two posterial limbs for three times. Blood and liver samples were obtained to determine the activity of total superoxide dismutase（tSOD）, malondialdehyde（MDA）, ALT and AST, liver wet/dry weight（W/D）, and the expression of TNF-a. The ultrastructural damage of the liver was observed as well. Results Compared with group I-R,the activities of MDA,ALT and AST were significantly decreased, tSOD level was increased and W/D and the expression of TNF-a were obviously reduced in group LIPC（P〈0. 01）. The damage of liver tissue was significantly less in group LIPC than that in group I-R. Conclusion LIPC has an delayed protective effect on liver I-R injury in rats,which is possibly related to an increase of the antioxidant capacity, suppression of liver inflammatory reaction, inhibition of the expression of TNF-a and improvement of liver microcirculation.