二甲肼诱发大鼠大肠癌超微结构的观察

本实验以二甲肼[1,2-Dimethylhydrazine,DMH]为致癌剂诱发大鼠大肠癌。电镜观察24只大鼠在DMH作用下,不同时相点,大肠粘膜显示不同程度的病变。实验10～15周主要表现为粘膜不典型增生,超微结构改变主要显示细胞膜不规则或皱褶,核增大、微绒毛不规则。第16～32周以后肿瘤形成,胞核显著增大,异染色质增多,胞质内分泌颗粒减少,游离核蛋白体增多、细胞膜表面微绒毛不规则,细胞膜之间的桥粒减少,此种改变为大肠癌的超微结构特征。

Ultrastructural study of 1,2-DMH induced colorectal carcinoma in rats

The ultrastructure of the 1,2-dimethylhydrazine (1,2-DMH) induced colorectal carcinoma was studied in rats. The ultrastructural changes varied with the elapse of time. In the 10th to 15th week after 1,2-DMH injection, the cell membrane of the epithelial cells of the colorectal mucosa was irregular or rugous, their nuclei enlarged and the microvilli irregular. In the 16th to 32nd week, the carcinoma was well-formed. The nuclei of the cells of the adenocar-cinoma were markedly enlarged with increased amount of heterochromatin( in the cytoplasm, there was a decrease of mucinous granules and an increase of ribosomes; and on the surface of the cells, the microvilli were irregular and the desmosomes between cells were decreased in number. These were the ultrastructural characteristics in the carcinogenesis of colorectal carcinomas.