低剂量辐射诱导的旁效应及其机制的初步研究

Low dose radiation induced bystander effect and its mechanism

目的研究低剂量照射（6cGy）的骨髓细胞悬液，离心后得到的上层相（简称条件液）对正常或辐射损伤细胞能否产生刺激性辐射旁效应，并探讨其发生机制。方法条件液与受0、2或5Gy照射的骨髓细胞悬液进行混合培养，使用MTF比色法观察各组细胞的增殖能力。同时采用细胞色素C还原法测定培养介质中听的浓度，以及运用免疫组织化学法检测细胞内c—fos的蛋白表达。结果受大剂量照射的细胞与条件液共培养后，其增殖能力与对照组比较，差异有统计学意义（P〈0．01），且伴随着O2^-浓度升高和c—fos蛋白表达的上调（P〈0．05）。结论低剂量辐射可对辐射损伤细胞产生促进其增殖的刺激性辐射旁效应，发生机制可能O2^-浓度的提高与c-fos蛋白表达的上调有关。

Objective To investigate whether the supernatant （the conditioned fluid） of myeloid cells suspension after low dose radiation （6 cGy） in vitro could result in hormesis on the normal or radiation damage ceils and its mechanism. Methods Mice myeloid cell suspension was irradiated by 0, 2 and 5 Gy, respectively, and cultured in vitro. MTT method was used to measure the reproductive activity of cells. Cytochrome C reduction method was used to determine the concentration of O2^- , the immunohistochernical method to test the protein expression of c-los. Results Co-cultured with the conditioned fluid, the reproductive activity of the myeloid cells after high dose irradiation（ P 〈 0.01 ）, while both the concentration of O2^- and the protein expression of c-los were enhanced （P 〈 0.05 ）. Conclusions The conditioned fluid could enhance the proliferation of the myeloid cells after radiation injury. The mechanism of the low dose radiation-induced bystander effect might be correlated with the increase of both the concentration of O2^- and the protein expression of c-los.