中文摘要：

目的 研究^60Coγ射线照射对体外培养的心肌细胞活性及凋亡的影响。方法 体外培养新生大鼠心肌细胞，分为对照组和照射组，照射组细胞分别用^60Coγ射线5Gy、10Gy、20Gy单剂量照射心肌细胞，照射后48h检测细胞培养上清中乳酸脱氢酶（LDH）浓度，流式细胞仪检测^60Coγ射线照射对体外培养的心肌细胞凋亡的影响，照射后48h及120h用结晶紫试验及MTT试验检测照射后心肌细胞活性变化，结果 照射组LDH浓度明显高于未照射组，且随照射剂量增加而升高。照射后48h凋亡细胞较对照组升高，凋亡细胞比例与照射剂量呈正相关。结晶紫试验及MTT试验均提示照射后48h照射组心肌细胞活细胞活性与对照组无明显差异，照射后120h照射组活细胞活性明显低于对照组，且与照射剂量相关。结论 ^60Coγ射线单剂量照射可直接损伤心肌细胞，降低体外培养的心肌细胞活性，促进心肌细胞凋亡。。

英文摘要：

Objective It is reported that radiation -induced myocardial degeneration in the rat is preceded by changes in capillary structure and function. The aim of the present study is to investigate direct effect of gamma ray radiation on activity and apoptosis of cultured rat cardiomyocytes in vitro. Methods The study was performed using primary cell cultures of cardiomyocytes isolated from hearts of now - born rats. After being cultured for 72h in vitro, cardiomyocytes were irradiated with single dose of 5Gy, 10Gy,20Gy of gamma ray respectively. At 48h post- irradiation,the concentration of LDH in the supernatant of cell culture was tested using methods introduced by International Federation of clinical chemistry （IFCC）, and apoptosis was determined with flow cytometry. The viability of myocytes was determined with crystal violet test and MTT test at 48h and 120h post - irradiation respectively. Results LDH concentration in the supernatant of cell culture of cardiomyocytes were increased significantly with the irradiation dose augment. Flow cytometry confirmed the iuduction of apoptosis in response to different gamma ray doses irradiation at 48h after irradiation. The viable cardiomyocytes irradiated by gamma ray were significantly declined at 120h after irradiation compared to un - irradiated cells, however there were no significant difference between two groups at 48h post - irradiation. Dose - effect relationship was demonstrated between cardiomyocyte apoptosis, viability and irradiation dose in the study. Conclusion The study demonstrates gamma ray radiation can cause direct damage to cultured cardiomyocytes, including inhibiting activity and inducing apoptosis of cardiomyocytes in vitro, which shows dose effect relationship. The mechanism of gamma ray irradiation induced injury to cardiomyocytes shoud be investigated futher.