| Objective Observing the changes of Treg/Th17 balance and the expression of matrix metalloproteinase 9(MMP9)to explore the effect and possible mechanism of dihydromyricetin(DMY)on mice with ulcerative colitis(UC).Methods Sixty BALB/c mice were divided into six groups randomly,normal control group,model group,DMY low-dose group(50mg/kg·d-1),DMY middle-dose group(100mg/kg·d-1),DMY high-dose group(200mg/kg·d-1)and 5-ASA group(50mg/kg·d-1).The normal control group mice were fed with distilled water,and other groups mice were provided 4﹪DSS to induce the acute UC models during seven days,and simultaneously accompanying a certain amout of drugs gastric gavage treatment.Mice were sacrificed seven days later and the disease activity index(DAI),tissue damage index(TDI)were calculated,the percentage of Treg cells and Th17 cells in CD4+T cells in peripheral blood were measured by flow cytometry,and Western-blot was used to detect the expression level of MMP9 in colon tissues.Results(1)Colon length: Compared with the normal control group,the colon length of the model group(8.10±0.89 vs 10.65±1.00)was shortened(p<0.05),and there were no significant differences in statistics among other groups.(2)Spleen index: Compared with the normal control group,the spleen index of the model group(7.00±0.96 vs 4.44±0.43)was significantly increased(p<0.01).Compared with the model group,the spleen index of DMY low-dose group(5.54±0.94 vs 7.00±0.96),DMY high-dose group(5.81±0.75 vs 7.00±0.96)and 5-ASA group(5.59±1.18 vs 7.00±0.96)were significantly decreased(p<0.01),and there was no significant difference in statistics between DMY high-dose group and 5-ASA group.(3)DAI: Compared with the normal control group,the DAI of the model group(8.33±0.42 vs 0)was significantly increased(p<0.01),while the DAI of DMY middle-dose group(6.00±0.00 vs 8.33±0.42),DMY high-dose group(4.57±0.51 vs 8.33±0.42),5-ASA group(4.71±0.39 vs 8.33±0.42)were decreased than that of model group,the differences were statistically significant(p<0.01),and there was no significant difference in statistics between DMY high-dose group and 5-ASA group.(4)TDI: Compared with the normal control group,the TDI of the model group(7.33±0.82 vs 0)was significantly increased(p<0.01).Compared with the model group,the TDI of DMY middle-dose group(4.86±0.69 vs 7.33±0.82),DMY high-dose group(2.71±0.76 vs 7.33±0.82)and 5-ASA group(2.28±0.76 vs 7.33±0.82)were significantly decreased(p<0.01)and there were significant statistical differences between DMY low,middle-dose group and DMY high-dose group(7.00±0.82 vs 2.71±0.76,4.86±0.69 vs 2.71±0.76,p<0.01).(5)Treg cells: Compared with the normal control group,the proportion of Treg cells in the peripheral blood of the model group(2.12±0.89 vs 4.30±0.59)was significantly decreased(p<0.01).Compared with the model group,the proportion of Treg cells in peripheral blood of DMY high-dose group(3.17±0.47 vs 2.12±0.89)was significantly increased(p<0.05),and there were no significant differences in statistics among other groups.(6)Th17 cells: Compared with the model group,the proportion of Th17 cells in peripheral blood of DMY middle-dose group(14.53±3.70 vs 40.81±22.36)and 5-ASA group(16.37±2.64 vs 40.81±22.36)were significantly decreased(p<0.01),and there were no significant differences in statistics among other groups.(7)Treg/Th17 ratio: Compared with the normal control group,the Treg/Th17 ratio of the model group significantly(0.0534±0.0032 vs 0.1219±0.0354)was significantly decreased(p<0.01),while the Treg/Th17 ratio of the DMY low-dose group(0.1126±0.0047 vs 0.0534±0.0032),DMY middle-dose group(0.2426±0.0780 vs 0.0534±0.0032),DMY high-dose group(0.1367±0.0380 vs 0.0534±0.0032)and the 5-ASA group(0.2117±0.0124 vs 0.0534±0.0032)were significantly higher than that of the model group(p<0.01).There was no significant difference in statistics between DMY high-dose group and 5-ASA group.(8)The expression of MMP9 in the model group was significantly increased than that in the normal control group(p<0.01),while its expression in the DMY treatment groups was significantly decreased than that in the model group(p<0.01),and with the treatment dose increasing,the more obvious MMP9 decreasing.Conclusion(1)DMY can significantly alleviate the inflammation of mice with ulcerative colitis induced by DSS and is positively correlated with the dose.(2)The possible mechanism of DMY in the mice with ulcerative colitis is to restore the balance of Treg/Th17 in peripheral blood and decrease the expression of MMP9 in colonic tissue.(3)DMY may become one of the candidate drugs for clinical treatment of UC. |
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