Effect of portulaca oleracea polysaccharide on treating ulcerative colitis induced by TNBs in rats

[Objective] To discuss the mechanism of portulaca oleracea polysaccharide(POP) on treating ulcerative colitis induced by TNBs in rats.[Methods] Forty-eight SD rats were randomly divided into 3 equal groups:normal group(n =16),model group(n =16),POP group(n =16).The rat model of ulcerative colitis was induced by an enema of 100 mg/kg of TNBS and 50% ethanol.Beginning from the third day,except for the normal group,each group was treated with an enema of 0.9% NACL,POP respectively.The rats were sacrificed 1 week later.Apoptosis of lymphocyte were detected with the technique of transmission electron microscope while Bcl-2 / Bax and Caspase-3 proteins expressions were assayed with IH staining.The mucin secretion in rats with UC was assayed by mucin special coloration histochemistry.[Results] The apoptosis rate of lymphocyte in model group was not distinct.The expression of Bcl-2 protein was increasing while the expression of Bax and Caspase-3 protein decreased.Compared with the POP group,the difference was significant(P 0.01).[Conclusion] POP exerted a therapic effect on UC-induced by TNBs possibly by promoting lymphocyte apoptosis through upregulating the expression of Bax,Caspase-3 and through down regulating the expression of Bcl-2 as well as enhancing mucin secretion.