肝细胞生长因子在大鼠心肌细胞放射损伤中的抗凋亡作用

Hepatocyte growth factor protects cultured rat cardiomyocytes against apoptosis induced by gamma ray irradiation

目的研究肝细胞生长因子(HGF)对^(60)Coγ射线照射诱导的体外培养心肌细胞凋亡的保护作用。方法体外培养新生Wistar大鼠心肌细胞,分为未照射组(A组)、单纯照射组(B组)、HGF(20ng/ml)处理照射组(C组)、HGF(40ng/ml)处理照射组(D组)。B、C、D组分别用^(60)Coγ射线20Gy单剂量照射心肌细胞,C、D组细胞在照射前3h分别用终浓度为20、40ng/ml的HGF孵育。照射后48h检测培养上清中的LDH浓度,用流式细胞仪检测心肌细胞生长周期及细胞凋亡率变化。结果照射后48h,B、C、D组细胞培养上清中的LDH浓度较A组升高,C、D组的LDH浓度较B组下降;B、C、D组细胞生长周期较A组无明显变化,但凋亡细胞比例较A组升高,经HGF孵育的心肌细胞凋亡率则呈下降趋势。结论^(60)Coγ射线单剂量照射可造成体外培养的心肌细胞损伤,促进心肌细胞凋亡,HGF可抑制^(60)Coγ射线对体外培养的大鼠心肌细胞的促凋亡作用,其机制仍需进一步研究。

Objective Hepatocyte growth factor （HGF） has been proposed to be used as an endogenous cardioprotective agent. The aim of the present study was to investigate the anti-apoptosis effect of HGF on rat cardiomyocytes after being irradiated by single dose gamma ray. Methods The study was performed using primary cell cultures of cardiomyocytes isolated from hearts of new-born rats. After being cultured for 72h in vitro, eardiomyoeytes were irradiated with gamma ray in a single dose of 20Gy. In the HGF treated groups, cells were incubated with HGF in the dose of 20 and 40ng/ml 3h prior to irradiation, respectively. At 48h post-irradiation, the concentration of LDH in the supernatant of cell culture was determine＆ Apoptosis and cell cycle were determined with flow cytometry. Results LDH concentration in the supernatant of cell culture of irradiated eardiomyocytes was increased significantly compared to that of un-irradiated cells （P〈20. 05）, however, LDH concentration was decreased in 40ng/ml HGF treated group compared to that of other irradiated groups （P〈20. 05）. Flow cytometry analysis confirmed the induction of apoptosis of eardiomyocytes in response to gamma ray irradiation of 20Gy in single dose at 48h after irradiated in comparision with that of un-irradiated cells （P〈0. 05 or P〈0. 01）. However, apoptosis was attenuated in HGF treated groups. 40ng/ml HGF significantly protected eardiomyocytes against irradiation-induced apoptosis compared with other irradiated groups （P〈0. 05 or P〈0. 01）. Flow cytometry showed minor change in cell cycle of irradiated cells, but there was no significant difference between every two groups. Conclusion These data showed that gamma ray irradiation can cause direct damage to and induce apoptosis of cardiomyocytes. HGF may afford protection to eardiomyocytes against gamma ray irradiation-induced apoptosis. The mechanism of irradiation induced injury to cardiomyocytes and HGF action in the process should be investigated further.