无创性肢体缺血预适应对大鼠缺血再灌注损伤心肌基质金属蛋白酶的影响

Effect of noninvasive limb ischemic preconditioning on myocardium matris metalloproteinases induced by ischemia/reperfusion in rats

目的观察大鼠无创性肢体缺血预适应(LIP)对心肌缺血再灌注损伤后心肌形态学、梗死面积和心肌MMP-2、MMP-9和TIMP-1的影响。方法通过连续3 d每天1次3个循环的下肢无创性5 min缺血、5 min再灌建立LIP模型。大鼠随机分成3组,心肌缺血再灌注组(I/R)、心肌缺血预适应组(CIP)和LIP组。以HE染色法观察心肌形态学改变;红四氮唑染色法确定心肌梗死范围,IS=IA/AAR×100%;免疫组化法测定心肌MMP-2、MMP-9和TIMP-1水平。结果缺血30 min再灌注120 min后,I/R组IS为(44.5±8.1)%;与I/R组比较,CIP和LIP均能明显改善心肌损伤的形态学改变,降低心肌细胞的肿胀、减少间质出血和炎性细胞的浸润。CIP使IS降低35.7%,缺血区心肌MMP-2降低42.1%,MMP-9降低43.3%,TIMP-1水平增加40.0%;LIP使IS降低42.9%,缺血区心肌MMP-2降低41.2%,MMP-9降低46.6%,TIMP-1水平增加53.8%。结论LIP不仅能改善缺血再灌注损伤大鼠心肌形态学改变、减少心肌梗死面积,而且能降低心肌细胞基质的损伤,起到保护心肌的作用。

Objective To determine whether noninvasive limb ischemic preconditioning （LIP） produces cardioprotective effect on ischemia-reperfused myocardium and to observe the role of matris metalloproteinases （MMPs） in this effect. Methods LIP was performed in rats by a repeated three-cycle （5 min ischemia 5 rain reperfusion） of hind limb everyday for three days. The rats were randomly divided into 3 groups： I/R group, myocardial ischemic preconditioning （CIP） group and LIP group. The morphologic changes were observed using HE dyeing. The area at risk （AAR） and infarct area （IA） were determined using Trypan blue and triphenyl tetrazolium choride （TTC） staining respectively. The infarct size （IS） was defined as IA/AAR 100%. MMP-2,MMP-9 and TIMP-1 in different myocardial areas were determined by immunohistochemistry. Results During 30 min myocardial ischemia and subsequent 120 rain reperfusion, the IS was （44. 5 ± 8.1 ）%. Comparing with I/R, the myocardial swelling, inter-stitial hemorrhage and inflammatory cell infiltrate decreased in both of CIP group and LIP group, and the IS reduced 35.7% in CIP group and 42. 9% in LIP group. The level of MMP-2, MMP-9 decreased in CIP group （42. 1% and 43.3% ） and LIP group was 41.2% and 46. 6%, but the level of TIMP-1 increased in CIP group （40. 0% ） and LIP group （53.8%）. Conclusion LIP only reduces the infarct area in myocardium but also prevents cardiac matrix from degrading after the myocardial ischemia-reperfusion. The MMPs play an important role in the myocardial protection provided by LIP.