DNA诱发损伤的修复与染色体畸变的研究—咖啡因对人精子染色体的影响

应用人精子去透明带卵异种体外受精技术，对第１次卵裂中期相的染色体畸变进行分析。实验分为对照、咖啡因后处理、丝裂霉素Ｃ（ＭＭＣ）预处理、ＭＭＣ预处理同时加咖啡因后处理４个组。咖啡因组、ＭＭＣ组和ＭＭＣ＋咖啡因组染色体结构畸变精子率依次为２７．０％，２３．０％和４５．０％；断裂均数依次为０．７２，０．６０和１．６５，各组上述参数均高于空白对照组（８．０％，０．１４），差异非常显著（Ｐ＜０．０１，Ｐ＜０．０１）。与ＭＭＣ组和咖啡因组相比较，ＭＭＣ＋咖啡因组诱发的染色体型和染色单体型畸变均明显增加，以染色体型畸变增加更为明显（Ｐ＜０．０１，Ｐ＜０．０１）。结果显示，咖啡因可诱发人精子染色体畸变并能通过抑制金黄地鼠卵母细胞的复制前和复制后修复系统，有效地增强ＭＭＣ对人精子染色体的诱变效应。

REPAIR OF DNA INDUCED LESIONS AND CHROMOSOMAL ABERRATIONS:THE EFFECTS OF CAFFEINE ON HUMAN SPERM CHROMOSOMES

Chromosome aberrations were analyzed at the first cleavage metaphase of zona-free hamster eggs fertillized in vitro with human sperm.The experiment was divided into four groups:control,caffeine post-treatment,mitomycin C (MMC) pretreatment and MMC pre-treatment + caffeine post-treatment.Frequencies of chromosome aberrations in Caffeine,MMC and MMC+Caffeine groups were 27%,23% and 45%,and the means of breakages were 0.72,0.60 and 1.65 sequentially.All of above parameters were statistically higher than those in control (8.0%,0.14)(P<0.01,P<0.01).Compared with those in Caffeine and MMC groups,the increases in the frequencies of chromatid-type and chromosome-type aberrations were highly significant in MMC+Caffeine group(P<0.01,P<0.01).A far higher frequency of chromosome-type aberrations than that of chromatid-type ones was found.These results showed that caffeine could induce chromosomal aberrations in human spermatozoa and potentiate the effects of MMC induction by inhibiting the pre- and post-replication repair system in hamster oocytes.