无创性肢体缺血预适应对大鼠心肌缺血/再灌损伤后心肌凋亡的影响

目的观察无创性肢体缺血预适应(NLIP)对心脏缺血/再灌损伤后心肌凋亡的影响而进一步探讨其对心脏的延迟保护作用。方法通过连续3 d每天1次,3个循环下肢无创性5 min缺血5 min再灌建立NLIP模型。实验分3组:心肌缺血/再灌组(I/R)、心脏缺血预适应组(IP)、NLIP组。再灌末取心肌组织,以四氮唑染色法测定心肌梗死面积(IS/AAR×100%);以TUNEL法检测细胞凋亡并且用免疫组织化学法检测凋亡基因的表达;分离心肌细胞,用流式细胞仪检测细胞凋亡率以及凋亡基因表达率。结果与I/R组(47.6%±7.5%)比较,IP和NLIP能明显降低梗死面积(24.6%±8.7%和23.1%±7.4%,P<0.01);流式细胞仪检测结果表明,在I/R组,细胞凋亡率高(16.21%±2.12%),Bcl-2/Bax比值低(0.66±0.03),IP和NLIP能明显降低细胞凋亡率(5.30%±0.81%,4.82%±1.15%,P<0.01),提高Bcl-2/Bax的比值(1.44±0.08,1.51±0.09,P<0.01);免疫组化染色结果与其一致。结论NLIP对心肌缺血/再灌损伤具有保护作用,机制可能与其对抗心肌细胞凋亡有关。

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

Aim To observe the effects of limb atraumatic ischemic preconditioning(NLIP) on the apoptosis after myocardial ischemia-reperfusion(I/R) injury in rats.Methods NLIP was performed in rats by a repeated three-cycle 5-min ischemia-reperfusion of hind limb everyday for three days.Three experimental groups were included:I/R,IP and NLIP.The area at risk(AAR) and infarct area(IS) were determined using Trypan blue and triphenyl tetrazolium choride(TTC) staining respectively.The infarct size was defined as IS/AAR×100%.To detect the apoptosis and the rate of Bcl-2/Bax,TUNEL,immunohistochemistry and flow cytometry method were adopted.Results Compared with I/R group(47.6%±7.5%),IP and NLIP could decrease IS/AAR(24.6%±8.7% and 23.1%±7.4%,P<0.01).The results detected by flow cytometry showed that in I/R group,apoptosis rate was high(16.21%±2.12%),and the rate of Bcl-2/Bax was low (0.66±0.03),but IP and NLIP could decrease apoptosis rate(5.30%±0.81%,4.82%±1.15%,P<0.01),and increase Bcl-2/Bax(1.44±0.08,1.51±0.09,P<0.01).Results of TUNEL and immunohistochemistry were in coincidence with the above.Conclusions NLIP can protect against myocardial injury,and the mechanism may be related to preventing apoptosis.