Study On HPRT Gene Locus Mutation Induced By Radiation Using Brdurd Labeling

Objective To study the relation between HPRT gene mutation of rat and of human peripheral blood lymphocytes and the dose of exposure to radiation with BrdUrd labeling method. Methods The whole experiment include two parts. In the first part of the experiment we studied the relation between the HPRT gene mutant frequency(MF) of rat peripheral blood lymphocytes and the dose or dose rate of internal exposure to late fission products. For different accumulated dose groups: the late fission products were injected into the bodies of some rats through the tail vein (The control group were injected with normal saline) , then 0, 1, 5, 10 and 15 days later, the blood were sampled by the method of cardiac puncture. Using the method of BrdUrd labeling which has been established, we got the MF of the HPRT gene of the rats. For different dose rate groups: The late fission products with specific activity were injected into four groups of rats. When the accumulated doses of the rats were nearly equal, we sampled the blood and got the MF of HPRT gene by the same way as above. In the second part of the experiment, the blood, donated by a young man, were separated into 5 portions with the same amount. After four portions exposed to different doses of Y -ray, the MF of HPRT gene for each portion were got. Results With the increment of the accumulative internal exposure dose, the MF of the HPRT gene rose accordingly. The MF of the other exposure rats are significantly different from the control group respectively except theIIIgroup 1. There is a linear relation between the radiation doses and the HPRT gene MF. It can be described as the following regression equation:Y=6.53 lO+0.3454X(r =0.9846). Similarly, the relationship also exists between the MF and the dose rates of the different groups, and the equation is Y7.8062+0. 151 OX (r =0.8669). In the second part, it also showed that there is a relation between the doses of the ~?-ray and the MF of the HPRT gene: Y=0. 7306+0. 7774X+0. 0706X2(r =0.9952). In the second experiment, we noticed a significant reduction of the transformed lymphocytes when the external radiation dose increased. Conclusion According to the results of the research, It can be concluded that the BrdUrd labeling is a quick, simple and relatively sensitive method to study the mutations of the HPRT gene of somatic cells induced by the internal or external radiation exposure and the HPRT gene mutations could be used to calculate the dose of radiation.