β_2-AR过表达对大鼠心肌细胞存活率的影响及机制

The Changes of Survival Rate of Cardiomyocytes Influenced by Overexpressing β_2-adrenoceptors and its Mechanisms in Rat

目的观察β2肾上腺素能受体(β2-AR)过表达对成年大鼠心肌细胞在不同浓度的异丙肾上腺素(isoproter-enol,ISO)刺激下的保护作用及机制。方法分离培养成年大鼠心肌细胞,随机分为3组:正常组、转染EGFP基因的腺病毒组和转染人β2-AR-EGFP基因的腺病毒组。心肌细胞培养48 h后,用异丙肾上腺素在不同剂量(10-6mol/L,10-5mol/L,10-4mol/L)下刺激2 h,观察细胞在刺激前后的存活率的变化。采用Western blot检测心肌细胞β2-AR的表达。结果Western blot结果显示转染β2-AR-EGFP基因的腺病毒组β2-AR蛋白的表达量明显高于其余两组(P<0.05),在10-6mol/L,10-5mol/L浓度的ISO刺激下3组细胞的存活率校正值无显著性差异,在高浓度(10-4mol/L)ISO刺激下β2-AR过表达组细胞存活率校正值明显高于其余两组(P<0.05)。结论β2-AR过表达对高浓度(10-4mol/L)ISO刺激的成年大鼠心肌细胞的死亡有保护作用,其可能的机制是通过β2-AR与Gi蛋白的耦联作用。

Objective To investigate the protective effects of overexpression of β2-adrenoceptors on adult rat cardiomyocytes stimulated by different concentrations of isoproterenol （ISO） and its mechanisms. Methods Individual cells were isolated and cultured from adult rats. Cultured cardiomyocytes were randomly divided into a normal group and two groups which were infected with adenoviruses containing the sequence of EGFP and human 132-adrenoceptor-EGFP- Cultured for 48 h, observed the survival rates of the cardiomyocytes which were stimulated by different concentrations （10-6 mol/L, 10-5 mol/L, 10-4 mol/L）of isoproter- enol（ISO） pre and after 2 h, β2-AR expression was detected by Western blot . Results Western blot indicated that the group which transfected the Adv. with β2-AR gene β2-AR protein expression was obviously higher than the other two groups （P 〈 0.05 ）. There was no obviously difference in the correction value of the two groups stimulated by ISO of 10 -6 mol/L and 10 -5 mol/L, when stimulated by 10-4 mol/L ISO 132-adrenoceptors of transfected group was obviously higher than the other two groups （ P 〈 0.05 ）. Conclusion Overexpression of β2-adrenoceptors protect cultured adult rat cardiomyocytes from the high concentration（ 10-4 mol/L） of ISO,the mechanisms may be that β2-AR coupled to Gi Protein.