J.Jpn. Surg. Soc.. 82(10): 1280-1290, 1981

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Original article

STUDIES ON THE HISTOGENESIS OF DMH-INDUCED COLONIC CARCINOMA IN RATS

Chemical carcinogen, 1,2-dimethylhydrazine (DMH) was administered subcutaneously into Donryu rats to investigate the histogenesis of experimentally-induced colonic carcinoma. A small lesion in an early stage of tumorigenesis, which could not be found macroscopically, was identified under a dissecting microscope by staining the colonic mucosa with an alcian-blue solution. Then, the small lesion was examined histo-pathologically and autoradiographically.
The colonic carcinoma, most of which revealed histologically well-differentiated adenocarcinoma, was frequently noticed in distal colon. In contrast, signet ring cell carcinoma was found more often in the cecum and proximal colon than in distal colon. As the size of the lesions increased, degree of the glandular atypism was also increased in those confined whithin the mucosa. Autoradiographical study showed that ⁵H-thyrnidine uptake in the mucosa was enhanced as the severity of the atypism of the lesion increased.
From these histological and autoradiographical studies, it is reasonable to assume that many of the DMH-induced colonic carcinomas, especially the differentiated adenocarcinoma, originate from the adenomatous lesions in the mucosa, with an exception that some of the signet ring cell carcinoma may develop de novo.

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