β和γ射线照射肿瘤细胞的生物效应比较

A comparative study of biological effects on tumor cells between low-dose-rate β-irradiation and high-dose-rate γ-irradiation

目的 比较低剂量率β射线和高剂量率γ射线照射诱发肿瘤细胞生物效应特点。 方法 采用32 Pβ射线和6 0 Coγ射线照射人宫颈癌HeLa细胞系 ,用台盼蓝排除法和X gal衰老细胞染色法比较两种照射肿瘤细胞死亡方式的差异。结果 32 Pβ射线 (0 375cGy min)和6 0 Coγ射线 (2 0 6cGy min)照射HeLa细胞后 72h的结果表明 ,低剂量率 β射线抑制细胞增殖为渐进性 ,使多数的细胞在一个或几个细胞倍增周期后死亡 ,以增殖性死亡为主 ;高剂量率γ射线对细胞的抑制作用直接、迅速 ,细胞坏死比例高 ,增殖性死亡 (衰老 )比例低于持续低剂量照射方式。结论 不同的辐射方式对细胞的杀伤方式不同 。

Objective\ To elucidate the radiobiological mechanism underlying cancer treatment with low-dose-rate β-irradiation of ()^(32)P,by comparing the cell-killing pattern with high-dose-rate γ-irradiation of ()^(60)Co. Methods\ HeLa cells were exposed to low-dose-rate β-irradiation of ()^(32)P or high-dose-rate γ-irradiation of ()^(60)Co. Comparisons were made between these two types of radiations,focusing on the cell-killing patterns evaluated by radiation-induced reproductive cell death(senescence)and necrotic cell death through X-gal senescence staining and typan blue exclusion method respectively. Results\ The results showed that there were different cell-killing patterns in HeLa cells between ()^(32)P radiation at dose-rate of 0.375 cGy/min and that of ()^(60)Co at dose-rate of 206 cGy/min at 72 h post irradiation. In exposure to ()^(32)P,more HeLa cells were lost due to reproductive cell death than to ()^(60)Co. X-gal staining showed that senescent cell ratio in HeLa cells after exposure of ()^(32)P was higher than after that of ()^(60)Co which caused more necrotic cell death. Conclusions\ More reproductive and less necrotic cell death contribute to total cell loss in HeLa cells by radiation of ()^(32)P than by ()^(60)Co.Understanding the underlying mechanism of radiobiology in different radiations is helpful in radiotherapy of malignant tumor by choosing a more reasonable and effective procedure of treatment.\;