低剂量电离辐射和低浓度丝裂霉素C诱导小鼠生殖细胞交叉耐受性

本文研究了Ｘ射线与丝裂霉素Ｃ之间的交叉耐受性。首先用低剂量Ｘ射线（０．０５Ｇｙ，剂量率：０．０５Ｇｙ／ｍｉｎ）给小鼠全身均匀照射，３小时后腹腔注射损伤剂量的ＭＭＣ，对照组只给损伤剂量的ＭＭＣ；反过来，给小鼠低剂显ＭＭＣ，２４小时后，再给损伤剂量的ｘ射线（１．５Ｇｙ，剂量率：０．２９Ｇｙ／ｍｉｎ）照射，对照组注入等量的生理盐水，然后照射损伤剂量的ｘ射线。比较实验组和对照组的初级精母细胞染色体畸变率，结果发现ｘ射线与丝裂霉素Ｃ之间存在交叉耐受性。

CROSS INDUCTION OF ADAPTIVE RESPONSE BY LOWLEVEL RADIATION AND CHEMICAL MUTAGENES INMOUSE GERM CELLS

In this study,the cross adaptive responses induced by low dose X-rays or bylow concentrations of Mitomycin C(MMC)were observed in vivo in the primaryspermatocytes of mice. Mice were exposed to 0.05GyX-rays in advance, and 3hr later,MMC were injected intraperitoneally,the control group was given only MMC. Lowconcentration of MMC were injected intraperitoneally and 24hr later, the all were exposedtol.56GyX-rays;the controls were only exposed to l.5G X-rays. The frequency ofchromosome aberration(CA)was compared between different groups. The primary spermatocytes in the mice pre-exposed to a low dose radiation showed alow frequency of CA induced by l,3 or 5mg/kg of MMC,in vivo compared with the miceonly receiving either MMC. The low concentrations of MMC(0.1,0.5 or 2mg/kg)couldreduce the susceptibility of germ cells to induction of chromosome damage by a subsequentlarge dose of X-rays.