肢体缺血预处理对大鼠肝脏缺血再灌注致心肌损伤的影响

Effects of limb ischemic preconditioning on myocardial injury induced by hepatic ischemia-reperfusion in rats

目的探讨单侧后肢缺血预处理对大鼠肝脏缺血再灌注致心肌损伤的影响。方法成年雄性wistar大鼠72只，体重200～250g，随机分为3组（n=24），假手术组（S组）仅暴露肝门；肝脏缺血再灌注组（IR组）肝脏缺血60min后恢复灌注；后艘缺血预处理组（LIP组）阻断右侧后肢动脉、静脉和肌间侧支血流10min后恢复灌注，30min后建立肝脏缺血再灌注模型。于肝脏再灌注即刻、1、6h各处死8只大鼠，测定血清脑钠素（BNP）浓度和心肌细胞膜Na^＋-K^＋-ATP酶活性，观察心肌超微结构。结果与S组比较，IR组和LIP组心肌细胞膜Na^＋-K^＋-ATP酶活性降低，血清BNP浓度升高（P〈0．05或0．01）。与IR组比较，LIP组心肌细胞膜Na^＋-K^＋-ATP酶活性升高（P〈0．05），心肌病理损伤程度减轻。结论单侧后肢缺血预处理可减轻大鼠肝脏缺血再灌注致心肌损伤的程度。

Objective To investigate the effects of unilateral lower limb ischemic preconditioning（LTP） on myocardial injury induced by hepatic ischemia-reperfusion （I/R）. Methods Seventy-two adult male Wistar rats weighing 200-250 g were used in this study. The animals were anesthetized with intraperitoneal 10% chloral hydrate 3 ml/kg, tracheostomized and mechanically ventilated. Hepatic I/R was produced by occluding portal vein and hepatic artery for 60 min followed by reperfusion according to Pringle＇ s method. LIP was produced by tourniquet occlusion of right femoral artery and vein for 10 min followed by 30 min reperfusion before hepatic I/R. The animals were randomly divided into 3 groups （ n = 24 each） ： group Ⅰ sham operation; group H hepatic I/R and group Ⅲ LIP ＋ I/R. Eight animals were sacrificed at 0, 1 and 6 h of reperfusion respectively in each group for determination of the activity of Na^＋ -K^＋ -ATPase in cardiac myocyte and serum BNP concentration （ELISA） and electron-micrescopic examination of inyocardium. Results The ultrastructure of myocardium was normal in group S. There were vacuolization and condensation of mitochondria, endothelial cell necrosis and broken myofilament in I/R group. The cell damages were ameliorated in LIP group. The Na^＋ -K^＋ -ATPase activity was significantly decreased in I/R and LIP group as compared with S group and was significantly higher in LIP group than in I/R group. The serum BNP concentration was significantly higher in I/R and LIP group than in S group but there was no significant difference between I/R and LIP groups. Conclusion LIP can attenuate myocardial injury induced by hepatic I/R.