黄芩苷对再灌注心肌细胞保护作用及与心肌细胞自噬的相关性

摘要

目的：：探讨黄芩苷对再灌注心肌细胞保护作用及与心肌细胞自噬的相关性。方法：将48只大鼠随机分为4组（n=12）：假手术组，假手术+黄芩苷组，缺血再灌注组，黄芩苷处理组。术前7天每日1次灌胃，建立各组模型。统计各组同时间点的血流动力学及再灌注45 min 后心肌梗死面积情况，免疫印迹试验（Western blot）测定再灌注30 min 后心肌微管相关蛋白（ LC3-Ⅱ）及自噬体膜标记蛋白（Becl-1）表达情况，再灌注30 min 后检测线粒体膜通道转换孔（mPTP）开放情况。结果：假手术组和假手术+黄芩苷组心肌梗死面积极小，不便进行比较。缺血再灌注组心肌梗死面积（41.32±1.85）％，黄芩苷处理组心肌梗死面积（23.30±1.60）％，两组差异有统计学意义（P<0.001）。再灌注30 min 后 LC3-Ⅱ及 Becl-1蛋白表达量，缺血再灌注组（LC3-Ⅱ：1.051±0.005，Becl-1：1.169±0.002）和黄芩苷处理组（LC3-Ⅱ：0.863±0.009，Becl-1：0.943±0.005）较假手术组（LC3-Ⅱ：0.763±0.007，Becl-1：0.647±0.014）明显增加（P<0.01）；黄芩苷处理组较缺血再灌注组明显下降（P<0.01）。再灌注30 min 后烟酰胺腺嘌呤=核苷酸（NAD+）含量（nmol/mg），缺血再灌注组（6.02±0.33）和黄芩苷处理组（9.56±0.53）较假手术组（11.28±0.37）明显下降（P<0.01）；黄芩苷处理组较缺血再灌注组明显增加（P<0.01）。结论：黄芩苷对正常心肌细胞自噬无影响，但能显著减少缺血再灌注心肌梗死面积，降低再灌注后的过度自噬发生，其机制可能通过抑制 mPTP 开放从而减少自噬的相关诱导因素发挥作用。%Objective: To study the protective effect of baicalin on myocardial ischemia reperfusion injury and its correlation to myocardial cell autophagy in experimental rats. Methods: The animal models were established by intragastric infusion at 7 days prior operation in different groups.Atotal of 48 rats were divided into 4 groups: Sham operation group, Sham+baicalin group, Ischemia reperfusion (IR) group and Baicalin treatment group. n=12 in each group. Hemodynamics at different time points and myocardial infarction (MI) size at 45 min after reperfusion were recorded; protein expressions of LC3-II and autophagy-related Becl-1 at 30 min after reperfusion were examined by Westernblot analysis; the opening condition of mitochondrial membrane channel transition pore (mPTP) was detected by NAD+ content. Results: The MI sizes in Sham operation group and Sham+baicalin group were too small to compare; MI sizes in IR group and Baicalin treatment group were (41.32±1.85) % vs (23.30±1.60) %, P<0.001. Protein expressions of LC3-II in IR group and Baicalin treatment group were (1.051±0.005) and (0.863±0.009) which were both higher than Sham operation group (0.763±0.007), P<0.01;Becl-1 were (1.169±0.002) and (0.943±0.005) which were both higher than Sham operation group (0.647±0.014),P<0.01; LC3-II and in Becl-1 expressions in Baicalin treatment group were decreased than IR group, P<0.01. NAD+ contents (by nmol/mg) in IR group and Baicalin treatment group were (6.02±0.33) and (9.56±0.53) which were both lower than Sham operation group (11.28±0.37), P<0.001; NAD+ content in Baicalin treatment group was increased than IR group,P<0.01. Conclusion: Baicalin had no autophagy effect in normal myocardial cells, but it may decrease the MI size and reduce excessive autophagy in myocardial cells after IR which might be related to inhibiting mPTP opening.