Changes in cell proliferation and morphology in the large intestine of normal and DMH-treated rats following colostomy.
Colostomies were formed in the midcolon of normal and DMH-treated rats. Changes in cell proliferation in the mucosa adjacent to the colostomy and in the defunctioned distal segment were measured at seven, 14, 30, and 72 days using a stathmokinetic technique. Animals were given intraperitoneal injections of vinblastine and sacrificed three hours later; counts of mitotic and nonmitotic cells were made in tissue sections, and three-hour accumulated mitotic indexes were estimated. The results show that, except at seven days in DMH-treated rats, cell proliferation was unchanged in the colon proximal to the colostomy. Morphologic evidence of hyperplasia was seen in some animals at seven and 14 days. The defunctioned segment showed rapid atrophy of both mucosa and muscularis and a gradual but progressive decrease in cell proliferation. The morphology of the mucosa adjacent to the suture line in both functioning and defunctioned segments in normal and DMH-treated rats was abnormal in many animals. Abnormalities that were seen included collections of dysplastic epithelial cells in the submucosa, focal adenomatous changes, and intramural carcinoma formation. Aggregates of lymphoid tissue often were associated with carcinomas.
D000230:Adenocarcinoma / Q000601:surgery; D000818:Animals; D002455:Cell Division; D003110:Colonic Neoplasms / Q000601:surgery; D003125:Colostomy / Q000009:adverse effects*; D004127:Dimethylhydrazines; D006965:Hyperplasia / Q000473:pathology; D007420:Intestine, Large / Q000473:pathology*; D008297:Male; D008940:Mitotic Index; D009364:Neoplasm Recurrence, Local / Q000209:etiology*; D051381:Rats; D011919:Rats, Inbred Strains
D004127:Dimethylhydrazines