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背景:在转基因小鼠、大鼠等小动物实验中发现,心肌细胞特异性过表达β-肾上腺素受体可以改善其收缩功能,但目前尚缺乏在大型哺乳动物进行的有关实验报道。目的:探讨犬心肌细胞过表达β2-肾上腺素受体后心肌细胞收缩功能的改变及其可能机制。方法:采用胶原酶消化法分离培养犬心肌细胞,用携带β2-肾上腺素受体目的基因的重组腺病毒转染心肌细胞。转染48h后观察心肌细胞β2-肾上腺素受体蛋白表达及在基础状态和最大收缩状态下(以异丙肾上腺素10-6mol/L刺激)心肌细胞cAMP水平及收缩功能的变化。结果与结论:转染β2-肾上腺素受体的心肌细胞β2-肾上腺素受体蛋白表达及胞内cAMP水平明显增多(P<0.05),基础状态下收缩功能明显增强,但不改变最大收缩幅度百分比。说明β2-肾上腺素受体的过表达可能通过增加心肌细胞内cAMP水平改善心肌细胞的收缩功能。
BACKGROUND: In experiments of transgenic mice, rats and other small animals, it has been found that cardiomyocyte specific overexpression of β-adrenergic receptor can improve its contractile function. However, there are currently no reports on the experiments carried out in large mammals. Objective: To investigate the changes of cardiomyocyte contractile function and its possible mechanism after overexpression of β2-adrenoceptor in canine cardiomyocytes. Methods: Canine cardiomyocytes were isolated by collagenase digestion and transfected into cardiomyocytes with recombinant adenovirus carrying β2-adrenergic receptor gene. The expression of β2-adrenoceptor protein in cardiomyocytes was observed 48 h after transfection and the cAMP level and contractile function of cardiomyocytes in basal and maximal contractile state (stimulation with isoprenaline 10-6 mol / L) were observed. RESULTS AND CONCLUSION: The expression of β2-adrenoceptor protein and intracellular cAMP level were significantly increased in β2-adrenoceptor-transfected cardiomyocytes (P <0.05), and the systolic function was significantly increased in the basal state without changing the maximal contractile amplitude percentage. These results suggest that overexpression of β2-adrenergic receptors may improve myocardial contractile function by increasing intracellular cAMP level.