右冠状动脉急性缺血/再灌注时窦房结细胞凋亡与iNOS蛋白的表达

目的 观察在体兔右冠状动脉急性缺血/再灌注(L/R)时窦房结细胞凋亡与诱导型一氧化氮合酶(iNOS)蛋白表达的关系。方法 在体兔右冠状动脉根部结扎或放松制作窦房结缺血/再灌注模型,健康成年新西兰兔70只分7组:假手术对照组、I2h组、I2hR2h组、I2h+NS(生理盐水)组、I2h+SMT(iNOS抑制剂Smethylisothiourea,SMT)组、I2hR2h+NS组和I2hR2h+SMT组。采用末端标记TUNEL法、SP免疫组化法结合彩色图像分析技术,检测窦房结细胞凋亡指数(AI)及iNOS蛋白表达的积分光密度(A)值。结果 ①I2hR2h组AI及iNOS A值明显高于12h组(P<0.01);②应用iNOS抑制剂后,I2h+SMT组、I2hR2h+SMT组AI及iNOS A值均明显低于I2h组和I2hR2h。组(P<0.05或P<0.01)。结论 缺血诱导窦房结细胞凋亡,再灌注加重细胞凋亡和增加iNOS表达,且细胞凋亡指数与iNOS表达变化相一致。提示iNOS生成增多可能与缺血再灌注窦房结细胞凋亡密切相关。

Apoptosis and expression of iNOS protein in sino-atrial node cells during right coronary artery acute ischemia/reperfusion in rabbits

Objective To observe apoptosis and expression of iNOS protein in sino-atrial node cells during right coronary artery acute ischemia/reperfusion(I/R) of rabbit in vivo. Methods I/R model of SAN was established by occluding or loosening the root of right coronary artery. Seventy healthy adult rabbits were divided randomly into the following seven groups( n = 10) : Sham group, I2h group, I2hR2h group, I2h + NS group,I2h + SMT(inhibition of iNOS:Smethylisothiourea, SMT)group, I2hR2h + NS group, I2hR2h + SMT group. Apoptosis index (AI) of ischemia/reperfusion of sino-atrial node cells was checked by TUNEL staining method and optical density(A) of protein expression of iNOS was observed by means of immunohistochemistry and analysed by image analysis system. Results ①AI and iNOS A of I2hR2h group sino-atrial node cells were increased significantly as compared with that of I2h group( P < 0.01) ; ②AI and iNOS A of I2h + SMT group and I2hR2h + SMT group sino-atrial node cells were decreased significantly as compared with that of I2h group and I2hR2h group after injecting SMT( P < 0.01 or P < 0.05) .Conclusion Ischemia can induce apoptosis and reperfusion can aggravate apoptosis and increase expression of iNOS protein in the sino-atrial node cells, the change of AI is congruous with iNOS A. It shows that expression of iNOS protein probably has relation to apoptosis of ischemia reperfusion sino-atrial node cells.