| Background: Dextran sulfate sodium(DSS)-induced colitis mimics human Ulcerative Colitis (UC) in histological features, and it was observed that the concentrations of collagen fibers were significantly increased both in experimental colitis and in UC patients. Osteopontin involved in the pathogenesis of organic fibroses.Aims: To investigate the expressions of collagen and osteopontin in rats with DSS-induced ulcerative colitis, and the effects of prednisone, mesalazin, and azathioprine on them.Methods: Fifty male SD rats were randomly divided into two groups, group A (control group, 10 rats) and group S (experimental group, 40 rats). Rats in group A were free to drink distilled water. Rats in group S were given 3% DSS solution for 7 days and distilled water for another 10 days, and the procedure was repeated, then the rats were randomly subdivided into 4 groups with intragastric administration of different solution once a day for a continual 14 days: group B (distilled water), group C (prednisone,4.2mg/kg), group D(5-ASA, 210mg/kg) and group E(azathioprine,105mg/kg). The collagen fibers and the expression of osteopontin in the colonic tissue were assessed by Sirius red in saturated carbazotic acid staining and immunohistochemistry respectively.Result:⑴Contents of collagen fibers in the colon were 28.43±2.63% (group A), 50.21±2.74 %(group B), 51.13±2.72%(group C), 50.39±3.43%(group D), and 49.97±3.39%(group E). The collagen contents in group E were significantly higher than those in the another 4 groups respectively(P<0.01).⑵The levels of osteopontin expression were 0.0186±0.0052 (group A), 0.0635±0.0054 (group B), 0.0631±0.0043 (group C), 0.0666±0.0046 (group D), 0.0661±0.0046 (group E). The levels in group A were significantly lower than those in group B, C, D, E respectively(P<0.01).⑶There was a positive relationship between the collagen contents and the levels of osteopontin (r = 0.965, P = 0.000 <0.01).Conclusions: The results indicated that there was a tendency to develop fibrosis in intestinal wall, mainly in the submucosa, in rats with DSS-induced ulcerative colitis. And a standard dosage of prednisone, 5-ASA, or azathioprine could not decrease the fibrosis. |
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