不同β受体阻滞剂对大鼠心肌间隙连接结构作用的对比研究

目的比较三代β受体阻滞剂的代表药物卡维地洛、美托洛尔及普萘洛尔对大鼠心肌缺血再灌注损伤心肌间隙连接（GJ）结构的不同作用。方法将大鼠随机分为假手术组、缺血再灌注组、卡维地洛组、美托洛尔组及普萘洛尔组。除假手术组只穿线不结扎外,其余各组均结扎左冠状动脉前降支30min,然后松开结扎线复灌4h,建立心肌缺血再灌注损伤模型。于再灌4h末用免疫荧光和激光扫描共聚焦显微镜技术观察心肌间隙连接蛋白43（CX43）的分布及组成变化,用激光扫描共聚焦显微镜对CX43进行定量。结果与假手术组相比,缺血再灌注组CX43-GJ结构明显异常。与缺血再灌注组比较,卡维地洛组、美托洛尔组和普萘洛尔组CX43-GJ损伤减轻。各药物治疗组间比较,卡维地洛组CX43-GJ结构损伤最轻。结论各种β受体阻滞剂均具有保护心肌GJ结构的作用,以卡维地洛的作用最明显。

The effects of various beta-blockers on myocardial gap junction structure in rat with myocardial ischemia-reperfusion injury

OBJECTIVE: To compare the effects of carvedilol, metoprolol and propranolol on myocardial gap junction (GJ) structure in rat with myocardial ischemia and reperfusion injury. METHODS: Rats were divided randomly into five groups: sham operation group (SO), myocardial ischemia and reperfusion group (IR), IR + carvedilol group (CV), IR + metoprolol group (MT), and IR + propranolol group (PP). The left anterior descending branch was ligated for 30 minutes and reperfused for 4 hours (IR). After 4 h reperfusion, the distribution and composition of gap junctional connexin 43 (CX43) were observed by immunofluorescence and laser scanning confocal microscopy (LSCM), and the quantification of CX43 was measured by LSCM. RESULT: Compared with SO group, IR resulted in abnormal distribution and composition of CX43-GJ and the impairment of CX43-GJ was significantly attenuated by CV, MT and PP treatments with the best effect observed in CV group (P<0.05 vs. MT and PP). CONCLUSION: These results suggest that beta-blokers, especially, carvedilol, could significantly attenuate IR induced CX43-GJ impairment.