| Objective To observe the effect of dihydromyricetin on ulcerative colitis and to explore its possible mechanism.Methods 1.A total of 60 female BALB / c mice were randomly divided into 6 groups: normal group,control group,DHM low dose group,middle dose group,high dose group and 5-aminosalicylic acid control group,each group of 10 mice.2.In the group given the same day to drink the normal group of mice drinking distilled water,the remaining mice were given 4% DSS aqueous solution for self-drinking(recorded as day 1)and continuous drinking for 7 days.Start on the day of drinking 4% DSS aqueous solution,the DHM low dose group(50mg/kg/d),the middle dose group(100mg/kg/d),the high dose group(200mg/kg/d)and the 5-aminosalicylic acid control group(50mg/kg/d)were treated by intragastric administration for each group for 14 days.3.From the 1st day of drinking 4% DSS solution,the weight of mice was weighed every day,observation of mouse activity,coat color,stool shape,color,mental state and record,and the disease activity index(DAI)of each group was evaluated according to the daily record.4.On the 14 th day of administration,the mice were sacrificed by cervical dislocation,the mice were infected with the whole colon and spleen.The appearance of the colon was observed visually,the length of the colon was measured,the weight of the spleen was calculated and the spleen index was calculated;HE staining was performed under light microscope and the histological score of mice was observed;Western blot was used to detect the expression of TLR2 and TLR4 in colonic tissues of mice;The activity of NF-κB in colon tissue was detected by EMSA;The levels of inflammatory cytokines IL-1β,TNF-a and IL-6 were measured by ELISA before and after DHM treatment;The activity of MPO,NO and SOD in intestinal tissue was determined by Kit.Results 1.DAI Rating: Compared with the normal group,the model group score [(8.33±0.52)vs 0 ] had significant statistical difference(p <0.01);DHM low dose group,middle dose group,high dose group compared with the model group[(7.86±1.21)、(6±0)、(4.57±0.53)、(4.71±0.49)vs(8.33±0.52)],there was no significant difference in DHM low-dose treatment group(p >0.05),the other groups had significant difference(p <0.01);DHM high dose group and 5-aminosalicylic acid control group[(4.71±0.49)vs(8.33±0.52)] has no significant difference(p >0.05).2.Colon length: Compared with the normal group,the colon length of the DSS model control group was statistically significant(p <0.05);DHM dose group compared with the model group[(8.8±0.85)、(8.8±0.95)、(8.89±0.93)vs(7.77±0.43)],are statistically significant(p <0.05).There was no significant difference between DHM high dose group and 5-aminosalicylic acid control group[(8.89±0.93)vs(8.56±1.13)](p >0.05).3.Compared with the normal group,the spleen index of the model group was significantly higher than that of the normal group,which was statistically significant(p <0.01);DHM dose group compared with the model group were decreased[(5.64±0.94)、(5.88±1.26)、(5.81±0.66)vs(7.01±0.96)],more statistically significant(p <0.05);There was no significant difference between DHM high dose group and 5-aminosalicylic acid control group[(5.81±0.66)vs(5.59±1.78)](p >0.05).4.Histopathological score: The histopathological score of the DSS model control group was statistically significant(p <0.01),which was compared with the normal group;DHM dose group compared with the DSS model control group,[(7.00±0.82),(4.85±0.69),(2.71±0.76)vs(7.33±0.52)],are statistically significant(p <0.05);There was no significant difference between DHM high dose group and 5-aminosalicylic acid control group[(2.71±0.76)vs(2.29±0.76)](p >0.05).5.Detection of NF-κB activity in mouse colon tissue by EMSA method: Compared with the normal group,the expression of NF-κB in colonic tissue of model group was significantly increased(p <0.01);DHM dose group had a significant inhibitory effect on NF-κB(p <0.01),Compared with the salicylic acid the DSS model control group,there were statistical differences(p <0.01).6.Western blot was used to detect the expression of TLR2 and TLR4 in colon tissue of mice: Compared with the normal group,the expression of TLR2 and TLR4 protein in the colon tissue of the model group was significantly increased(p <0.01);The expression levels of TLR-2 and TLR-4 protein in intestinal tissue of DHM group were decreased(p <0.05),the high expression of TLR-2 and TLR-4 in intestinal tissue was significantly inhibited by DHM high dose group(p <0.01).The therapeutic effect was similar to that of 5-aminosalicylic acid.7.The levels of IL-1β,TNF-a and IL-6 were detected by ELISA: The results showed that the levels of IL-1β,TNF-a and IL-6 in the model group were significantly higher than those in the normal group(p <0.01);DHM group compared with the model group,the inflammatory factor content decreased significantly,more statistically significant.There was no significant difference between DHM high dose group and 5-aminosalicylic acid control group(p > 0.05).8.Detection of MPO,NO,SOD activity changes: The activity of MPO and NO in the model group was significantly higher than that in the normal group(p <0.01),SOD activity decreased significantly(p <0.01);The activity of SOD and MPO in DHM dose group and 5-aminosalicylic acid control group were statistically significant compared with the model group(p <0.05),while the NO activity compared with the model group,there were no statistical differences(p > 0.05);DHM high dose group and 5-aminosalicylic acid control group were statistical differences(p <0.05),which was compared with the normal group.Conclusions: 1.DHM can effectively relieve DSS-induced mouse colitis.2.DHM treatment of colitis may have the mechanism:(1)Inhibit the production of inflammatory factors by inhibiting TLRs / NF-κB pathway;(2)By inhibiting NO,protecting SOD activity reduces DSS-induced oxidative stress;(3)By inhibiting MPO activity;3.DHM may be one of the candidates for clinical treatment of ulcerative colitis. |
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