Objective To explore the changes of CD4~+CD25~+ and CD8~+CD28~-
T regulatory cells in rats with
experimental colitis induced
by 2,4,6-trinitrobenzenesulfonic acid (TNBS) after drug treatment with salicylazosulfapyridine(SASP) and prednisolone(PSL).Methods The model of
experimental colitis was established through TNBS enema.Thirty-nine adult SD rats were randomly divided into 5 groups: normal control group,experimental colitis model groups(1 week and 3 weeks),SASP therapeutic group,and PSL therapeutic group.The proportion of CD4~+CD25~+ and CD8~+CD28~-
T regulatory cells in peri-(pheral) blood,spleen mononuclear cells,and intraepithelial lymphocytes of rat colons were determined by flow cytometry.Results The rat model of TNBS-induced colitis was established successfully.The CD4~+CD25~+ Tr in peripheral blood,spleen mononuclear cells,and intraepithelial lymphocytes of colon from experimental colitis model group(1 week) were higher than those from normal control group.The level of CD4~+CD25~+ Tr in experimental colitis model group was decreased to that of normal control group after 3 weeks,and did not change after SASP treatment.The level of CD4~+CD25~+ Tr of PSL-therapeutic group was significantly lower than that of experimental colitis model group.The CD8~+CD28~-Tr in peripheral blood,spleen mononuclear cells,and intraepithelial lymphocytes of colon were higher in experimental colitis model group than in normal control group from 1 week to 3 weeks.The CD8~+CD28~-Tr of SASP therapeutic group was lower than that of experimental colitis model group in spleen mononuclear cells and intraepithelial lymphocytes of colon.The CD8~+CD28~-Tr of PSL therapeutic group was significantly lower than that of experimental colitis model group in peripheral blood,spleen mononuclear cells,and intraepithelial lymphocytes of colon. Conclusion CD4~+CD25~+ and CD8~+CD28~T regulatory cells may be have relations with the different phases of colitis.CD8~+CD28~-T cells are positively correlated with chronic inflammation;SASP and PSL have decreased the proportion of CD8~+CD28~-T regulatory cells,and have therapeutic effects on experimental colitis,especially PSL.