放射治疗对宫颈癌病人DNA损伤及hprt基因突变的初步研究

目的：评价放射治疗对宫颈癌患者造成的遗传学损伤。方法：取15例宫颈鳞癌放疗患者放疗前及放疗累积剂量为0Gy、10Gy、20Gy、30Gy、40Gy、50Gy、60Gy时的外周静脉血,以彗星实验检测淋巴细胞的DNA损伤,采用多核细胞法测hprt基因位点突变率。结果：各累积剂量组淋巴细胞DNA拖尾率比照射前显著升高（P〈0.01）,并且在0-60Gy之间,拖尾率与累积照射剂量之间成线性关系。各累积剂量组尾长比照射前均增加（P〈0.01）,在照射剂量累积30Gy时,尾长均值达最大。尾长与累积剂量间不成线性关系。hprt基因位点突变率在照射后升高,与照射前相比,在照射累积剂量为30Gy、40Gy和50Gy时,显示有统计学意义差别（P〈0.05）。hprt基因突变率与累积剂量间呈现较好的剂量-效应关系。结论：宫颈癌患者放疗后造成外周血淋巴细胞DNA损伤及hprt基因突变,hprt基因突变和彗星实验用于评价放疗造成的损伤,具有较高的敏感性。

DNA damage and hprt mutation in cervical cancer patients undergoing radiotherapy

Objective：To study the genetic damage induced by radiotherapy in cervical cancer patients.Methods： Blood samples were collected from 15 cervical cancer patients exposed to radiation at accumulated dose of 0Gy,10Gy,20Gy,30Gy,40Gy,50Gy,60Gy.To study DNA damage by comet assay.To study hprt gene mutation by multinucleated cell assay.Results：All the accumulated dose groups increased significantly according to 0Gy（P0.01）.The increase of the comet frequency was linear from 0-60Gy.The tail length showed significant increase at all the accumulated dose groups（P0.01）.At the accumulated dose of 30Gy,the tail length achieved the max value.There was no dose-effect manner between the tail length and the accumulated dose.Mutation frequency of hprt gene increased after radiation.The mutation frequency increased significantly at dose 30Gy,40Gy and 50Gy compared to 0Gy（P0.05）.There was a good dose-effect manner between mutation frequency of hprt gene and accumulated dose.Conclusion： Radiotherapy induced DNA damage and hprt gene mutation in cervical cancer patients.To assess the radiation-damage by comet assay and hprt gene mutation has a high sensitivity.