Effect of acute and chronic glucocorticoid treatments on epithelial cell proliferation in the esophagus and small intestine of rats
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Data about glucocorticoid influence on proliferation in the esophagus and small intestine are very contradictory and need to be reexamined. Moreover, only the effects of acute or short-term treatments with glucocorticoids have been demonstrated, whereas nothing is known about their effects under chronic exposure. This work was therefore carried out to examine proliferative activity in the esophagus and small intestine under conditions of acute and chronic glucocorticoid exposure. Rats were treated with either glucocorticoid triamcinolone acetonide or vehicle for 3, 33, or 63 days. Proliferation was assessed in the basal layer of esophageal epithelium and in the epithelium of jejunal crypts, using three criteria, as the number of mitotic, bromodeoxyuridine-labelled, and proliferating cell nuclear antigen-labelled cells. Treatment with glucocorticoid for 3 days led to a slight decrease in all parameters in the esophageal epithelium and had almost no effect on proliferation in the epithelium of jejunal crypts. Long-term treatment with glucocorticoid for either 33 or 63 days resulted in an increase in all parameters tested in both esophageal and jejunal crypt epithelia. Sixty-three-day treatment had a more prominent and significant (P < 0.05) effect. These results suggest that acute glucocorticoid treatment nonsignificantly reduces the number of cells in the cell cycle in the esophageal epithelium, whereas chronic treatment increases the number of proliferating cells in both esophageal and jejunal crypt epithelia.
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