Intestinal epithelium regeneration in rats receiving methotrexate and a trial of regulating this regeneration with pentagastrin and glucagon.

The study was carried out in three groups of rats: group I of 36 rats received methotrexate, group II of 36 rats were given methotrexate, pentagastrin and glucagon, group III of 12 rats served as control. For histological examination the ileum was taken from the animals killed on days 1, 2, 3, 4, 7 and 9 after the last injection of methotrexate. Besides histological examinations the mitotic index and the number of cells in crypt longitudinal-section were determined. Relatively low doses of methotrexate caused characteristic changes in the intestinal mucosa: disappearance of mitotic figures, shortening of crypts particularly on the first day after the last dose of methotrexate. On the following days regeneration processes were noted causing an excessive epithelial proliferation observed up to the 9th day after the last dose of methotrexate. This indicates that the mobilized mechanisms of epithelial proliferation stimulation exert their effect fairly long. In the group receiving methotrexate administration of pentagastrin and glucagon contributed to the increased number of mitoses in crypt epithelium and the number of cells on crypt longitudinal-section. These observations are an evidence of a beneficial effect of the hormones administered to the rats in the regeneration of the ileal epithelium damaged by the cytostatic agent.