1-methyl-3-nitro-nitrosoguanidine (MNNG) によるラット腸管上皮傷害、再生及び染色体異常

概要

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This experiment was designed to study the mucosal damage and repair with MNNG and the action of MNNG on chromosomes of epithelial cells of the digestive tract in Wistar rats. A blind blind loop of the colon without fecal passage was produced by placing an artificial anus. This empty loop was treated twice with MNNG. First, 5ml of 0.5% MNNG was injected into the blind colon per ani. The histology revealed severe damage of mucosal cells after 3 hours. They regenerated within 4th-6th days. In this regeneration process, the appearance of a thin film of epithelium over the granulation was observed. The second injection, 5ml of 0.1% MNNG, was given on the 4th day after the first injection. Chromosomal aberrations were studied 3-48 hours after the second treatment. Aberrant metaphases increased progressively from 6 hours reaching the maximal level at 15 hours. Early chromosome-damaging effect of MNNG may be an essential step of chemical carcinogenesis. On the other hand, intermittant administration of MNNG produced a minute cancer in a blind loop of the colon.
神戸大学の論文