远端缺血预处理对心肌缺血再灌注损伤后抗氧化能力的影响

Effect of remote ischemia preconditioning on antioxidant ability after myocardial ischemia/reperfusion injury

摘要:

目的：通过对心肌缺血再灌注损伤（ischemia/reperfusion injury，IRI）大鼠给予不同部位远端缺血预处理（remote is－chemia preconditioning, RIPC），观察其对心肌IRI保护作用的差异，并探讨抗氧化作用在其中的机制。方法：50只雄性SD大鼠随机分配成5组：对照组、股动脉对照组（无预处理措施，暴露双侧股动脉）、股动脉组（行双侧股动脉阻断的IPC）、主动脉对照组（无预处理措施，暴露主动脉）和主动脉组（行主动脉肾下水平阻断的IPC），预处理措施为3个循环的5 min阻断和5 min再灌注，之后建立心肌IRI模型（30 min缺血180 min再灌注）。实验结束后用黄嘌呤氧化酶法测定血清和心肌组织的超氧化物歧化酶（superoxide dismutase，SOD）活力，硫代巴比妥酸法测定丙二醛（malondialdehyde，MDA），自动生化仪测定血清乳酸脱氢酶（lactate dehydrogenase，LDH）、肌酸激酶同工酶（creatine kinase MB，CK-MB），酶联免疫吸附法测定肌钙蛋白Ⅰ（cardiac Troponin Ⅰ，cTnⅠ），取心脏标本行梗死面积、HE染色和TUNEL荧光染色，计算凋亡指数。结果：各组大鼠平均动脉血压基础值和缺血前无统计学差异（P＞0.05）。缺血后，除对照组，其余4组的平均动脉血压均有不同程度地下降（P＜0.05），主动脉组血压下降最明显和心肌梗死面积最大（P＜0.05）。与对照组比，其余4组血清的MDA增高（P＜0.05），SOD、LDH、CK-MB和cTnI降低（P＜0.05），心肌组织的MDA增高（P＜0.05），SOD降低（P＜0.05），其中主动脉对照组血清的MDA增高最明显（P＜0.05），SOD、LDH、CK-MB和cTnI降低最明显（P＜0.05），心肌组织的MDA增高最明显（P＜0.05），SOD降低最明显（P＜0.05）。对照组大鼠心肌细胞配列紧密，横纹清晰，其他4组均有不同程度的心肌细胞排列紊乱、血管扩张、炎性细胞浸润、出血，其中主动脉组的病变最明显。股动脉组和主动脉组心肌细胞凋亡指数均与对照组无统计学差异（P＞0.05）。结论：RIPC可能通过降低机体的脂质过氧化程度来发挥心肌IRI保护作用，但扩大RIPC的范围却并不能增大这种保护作用，表现为机体的抗氧化水平亦相应有所下降。

Abstract:

Objective：To discuss on the effect of remote ischemia preconditioning（RIPC） on antioxidant ability after myocardial ischemia/reperfusion injury（IRI） in rats. Methods：Totally 50 male SD rats were randomly allocated to 5 groups：control group，femoral control group，femoral group，aorta group and aorta control group. The same RIPC protocol was given and then heart IRI was created. At the end of the experiment，serum and heart tissue was obtained to test anti-/oxidation indexes and myocardial injury marker. Hearts were stained to HE and calculate cardiomyocyte apoptosis index（AI）. Results：There was no significant difference in the mean arterial blood pressure within 5 groups before ischemia（P>0.05）. After ischemia，compared with that of control group，mean arterial blood pressure of the other 4 groups was decreased（P<0.05）. The mean arterial blood pressure of the aorta group was the lowest and the area of myocardial infarction was the largest（P＜0.05）. Compared with that of control group，malondialdehyde（MDA） in the other 4 groups was increased（P<0.05），superoxide dismutase（SOD），lactate dehydrogenase（LDH），creatine kinase MB（CK-MB） and cardiac Troponin Ⅰ（cTnⅠ） were decreased（P<0.05）. The serum MDA in the aorta control group was significantly higher（P<0.05），and the SOD，LDH，CK-MB and cTnI were the lowest（P<0.05），and SOD was decreased（P<0.05）. In the control group，the myocardial cells were closely packed and the stripes were clear. The other 4 groups had disorganized cardiomyocytes，vasodilatation，inflammatory cell infiltration and hemorrhage，and the lesions in the aortic group were the most obvious. The apoptosis index of cardiomyocytes in the femoral artery and aorta groups was not significantly different from that in the control group（P>0.05）. Conclusion：RIPC may act against myocardial IRI thorough decreasing the lipid pero-xidation. However，the increased area of RIPC can not promote the cardioprotection and the antioxidant ability is also declined.