N-甲基-N′-硝基-N-亚硝基胍致大鼠气管上皮细胞体外转化及细胞遗传学改变

利用原代大鼠气管上皮(RTE)细胞研究N-甲基-N′-硝基-N-亚硝基胍(MNNG)的致转化作用，并对转化细胞进行细胞遗传学研究. 结果表明：增殖旺盛细胞(EGV)集落是RTE细胞体外转化最早期的特征，EGV转化频率与MNNG剂量呈明显的剂量反应关系. 从0.3 mg·L^-1 MNNG剂量组分离到2个EGV集落，经消化，传代形成了永生化的细胞系(RTES1,RTES2)，RTES1为多倍体核型，2号和7号染色体数目增加至4个且呈高频发生(100%); RTES2呈二倍体核型. 电镜结果证实转化细胞来自大鼠气管上皮组织. 以上结果提示，原代RTE细胞体外培养模型是研究致癌物定量及致癌机理的理想模型系统.

In vitro transformation and cytogenetic changes of rat tracheal epithelial cells by N-methyl-N-′-nitro-N-nitrosoguanidine

The primary rat tracheal epithelial(RTE) cells were used to study the cytotoxic potency and transforming effects by the chemical carcinogen N-methyl-N′-nitro-N-nitrosoguanidine(MNNG). Enhanced growth variant(EGV) colonies were the earliest feature during transformation of RTE cells．The transformation frequency increased with a single exposure to MNNG concentration from 0.05 to 0.6 mg·L^-1. Two EGV colonies were isolated from the 0.3 mg·L^-1 MNNG exposure. By expansion and successive passaging, they acquired indefinitely growth capacity．The cell line of RTES1 was multiploidy cells in which the occurrence of tetraploidy of chromosome 2 and 7 was in a very high frequency(100%). The RTES2 was diploidy which occupied the 69% of the cells examined. The electron microscopy showed that the cell line was derived from RTE cells. Our results suggest that the culture system of the primary RTE cells is an useful model in quantitative and carcinogenic studies．