β受体阻滞剂对乳鼠心肌细胞内质网应激致凋亡途径的影响

Effects of β-blockers on apoptosis of cultured myocardial cells induced by endoplasmic reticulum stress

目的通过体外培养乳鼠心肌细胞,探讨β受体阻滞剂对乳鼠心肌细胞凋亡率及内质网应激作用的影响。方法培养乳鼠心肌细胞,确定β受体阻滞剂的饱和浓度,原代培养乳鼠心肌细胞72h后给予β受体阻滞剂溶液和衣霉素溶液干预,实验分4组:空白对照组、50μg/ml美托洛尔组、10μg/ml衣霉素组、10μg/ml衣霉素+50μg/ml美托洛尔组。确定美托洛尔的饱和浓度;反转录-聚合酶链反应(RT-PCR)检测各组内质网应激指标GRP78、内质网应激致凋亡指标Caspase12,流式细胞术检测实验各组乳鼠心肌细胞凋亡率,确定美托洛尔对内质网应激致凋亡途径的影响作用。结果①美托洛尔的浓度为50μg/ml时,对内质网应激的影响已达最大。②与空白对照组比较,50μg/ml美托洛尔组心肌细胞内质网应激致凋亡指标Caspase12表达及心肌细胞凋亡率差异无统计学意义(P>0.05)。10μg/ml衣霉素组、50μg/ml美托洛尔+10μg/ml衣霉素组心肌细胞内质网应激致凋亡指标Caspase12及心肌细胞凋亡率较空白对照组均明显增加(均P<0.05),且在衣霉素组时心肌细胞中内质网应激致凋亡指标Caspase12及心肌细胞凋亡率均最高,而50μg/ml美托洛尔+10μg/ml衣霉素组与10μg/ml衣霉素组比较,心肌细胞内质网应激致凋亡指标Casepase12及心肌细胞凋亡率降低,差异有统计学意义(均P<0.05)。结论美托洛尔浓度在50μg/ml时为内质网应激保护的饱和浓度,β受体阻滞剂可以减轻内质网应激所致的凋亡途径。

Objective To explore the effects of β-blockers on apoptosis of cultured myocardial cells induced by endoplasmic reticulum stress in neonatal mice. Methods Neonatal rat cardiomyocytes were cultured and saturated concentration of β-blockers were determined. After primary culture for 72 h, neonatal rat cardiomyocytes were divided into the blank control group, 50 μg/ml β-blocker treated group, 10 μg/ml tunicamycin treated group, and 10 μg/ml tu-nicamycin plus 50 μg/ml β-blocker treated group. GRP78 as an indicator of endoplasmic reticulum stress and Casepase 12 as an indicator of endoplasmic reticulum stress induced apoptosis in each group were detected by RT-PCR, and the apoptosis rates of cardiomyocytes by flow cytometry, so as to explore the role of β-blockers in apoptosis induced by en-doplasmic reticulum stress. Results ①GRP78 was shown to achieve the greatest effect on endoplasmic reticulum stress with 50 μg/ml β-blocker. ②Compared with the control group, treatment with 50 μg/ml β-blocker alone did not singnificantly increased （P〉0.05）, but treatment with 10 μg/ml tunicamycin or 10 μg/ml tunicamycin plus 50 μg/ml β-blocker did significantly increase the expression of casepase12 and apoptosis rates of myocardial cells （both P〈0.05）. Such effect was stronger with 10 μg/ml tunicamycin treatment alone as compared with 10 μg/ml tunicamycin plus 50 μg/ml β-blocker （P〈0.05）. Conclusion β-blocker may be best protective against endoplasmic reticulum stress at the saturated concentration of 50 μg/ml. Moreover, β-blockers may ameliorate the endoplasmic reticulum stress-induced apoptosis.