^(137)Cs γ射线诱发CHL细胞遗传不稳定性

Genomic Instability induced by 137 Cs γ ray irradiation in CHL surviving cells.

目的研究辐射诱发的ＣＨＬ细胞遗传不稳定性在基因、染色体及细胞水平上的传递及表达情况。方法不同剂量一次照射ＣＨＬ细胞，于不同时间点分析受照存活细胞的ＨＧＰＲＴ位点突变、微核及细胞凋亡。结果ＣＨＬ细胞照射３Ｇｙ后５３天，其后代仍表达出显著升高的ＨＧＰＲＴ位点突变率。细胞照射３Ｇｙ后６小时的双核细胞微核率达（４１５１±３６１）％，３天后下降为（１４４７±２３９）％，５６天后为（１０５１±０８７）％，显著高于对照组（Ｐ＜００１）；而受照细胞子代双核率无显著变化，接种效率明显降低（３Ｇｙ剂量以上Ｐ＜００１）。细胞受照射３、４、６、９、１０Ｇｙ后，第２天细胞凋亡率达最大值，１０Ｇｙ剂量组为（２４９０±６７２）％，之后各剂量组细胞凋亡率迅速下降，但直到照射后１２天细胞凋亡率仍维持在１０％左右，显著高于对照组（Ｐ＜００１）。结论辐射诱发的细胞基因组不稳定性可以表现在基因、染色体及细胞等不同水平上，推测在其产生和传递过程中可能伴随着某些基因的改变。

Objective\ To study in parallel several possible manifestations of instability of surviving CHL cells after irradiation,namely the frequencies of mutation at locus,micronuclei and apoptosis.Methods The frequencies of mutation at hgprt locus,micronuclei and apoptosis were assayed at various times in surviving cells irradiated with γ rays.Results The surviving cells showed a persistently increased frequency of mutation at the hgprt locus after irradiation until 53 days.Mutant fraction as high as 10 -4 was scored,tens of times higher than those assayed in control cells studied in parallel.The frequency of binucleated cells with micronuclei determined within 24 hours after irradiation increased with dose and reached a peak value of (26.58±2.48)% at 3Gy,decreasing at higher doses to a plateau around 20%.The micronucleus frequency decreased steeply to about(14.47±2.39)% within the first 3 days post irradiation,and fluctuated at around 10% up to 56 days post irradiation.The delayed efficiency of irradiated cells was significantly decreased.The frequency of apoptosis peaked about(24.90±4.72)% at 10 Gy 48 h post irradiation(γ ray dose between 3 10 Gy)and then decreased to about 12% within 3 days.It was significantly higher than in control cells until 14 days.Conclusions It shows that genomic instability induced by radiation can be transmitted to the progeny of surviving cells and may take many forms of expression such as lethal mutation,chromosome aberrations,gene mutation,etc.