| Background:Ulcerative colitis(UC)is a chronic,relapsing inflammatory bowel disease(IBD)characterized by inflammation confined to the colonic mucosa or submucosa.The primary clinical features of UC are diarrhea,abdominal pain,hematochezia,and weight loss.The disease often has recurrent episodes and is difficult to cure.The imbalance in intestinal immunity,triggered by the interaction of environmental,genetic and intestinal microecological factors,results in continuous inflammatory damage to the intestinal mucosa.Currently,the effects of various drug treatments are not satisfactory.Thus,finding safer and more effective drugs for treating UC is of great importance.Sophora moorcroftiana(S.moorcroftiana),endemic to the Qinghai-Tibet Plateau,has been recorded in Tibetan medical books for its therapeutic effects on digestive diseases.In previous work in our laboratory,we extracted the water-soluble alkaloid E2 from S.moorcroftiana seeds and identified its main components are E2-a and E2-b.The key ingredients of E2-a are matrine and sophocarpine,while those of E2-b are oxymatrine and oxysophocarpine.Literature reports suggest that matrine,oxymatrine,sophocarpine and oxysophocarpine have anti-inflammatory effects,implying that the water-soluble alkaloids from S.moorcroftiana seeds could have therapeutic effects on UC mice.Therefore,this study seeks to explore the intervention effects and mechanisms of water-soluble alkaloids from S.moorcroftiana seeds on UC mice.Methods:C57BL/6 mice were randomly divided into nine groups:the Control group,DSS model group,5-ASA group,E2-a group,E2-b group,E2(50 mg/kg)group,E2(100 mg/kg)group,matrine group,and sophocarpine group.During drug intervention,Disease Activity Index(DAI)scores were calculated.At the end of the intervention,the spleen index was computed.Colon length was measured,and colon tissue was stained with H&E.Lymphocytes were isolated from mesenteric lymph nodes,and the proportions of Th17 and Treg cells were detected by FCM.Colon tissue was homogenized and used for the ELISA detection of IL-6,IL-1β,TNF-αand IL-28B concentrations.Western blot was used to assess the expression levels of p-STAT3,p-p38,p-p65 and p-IκBαproteins.Results:1.Evaluation of the intervention effects of water-soluble alkaloids from S.moorcroftiana seeds on UC mice:(1)The DAI scores showed that compared to the DSS model group,the DAI scores of the E2(100 mg/kg),E2-b and matrine groups were significantly reduced(P<0.01).(2)Measurements of colon length showed that the colon lengths of mice in the E2(100 mg/kg),E2-b and matrine groups were significantly longer than those in the DSS model group(P<0.05).(3)Observations from H&E staining found that compared to the DSS model group,the pathological damage to colon tissue was significantly less severe in the E2(100 mg/kg),E2-b and matrine groups.2.Study on the immunomodulatory effects of water-soluble alkaloids from S.moorcroftiana seeds on UC mice:(1)Spleen index results showed that the spleen index of the E2-b group was decline obviously than that of the DSS model group(P<0.01),while there were no significant differences in the other groups(P>0.05).(2)FCM was used to detecte CD3~+CD4~+IL-17A~+Th17 cells and CD4~+Foxp3~+Treg cells in mice mesenteric lymph nodes.The results showed that compared to the DSS model group,the proportions of IL-17A~+cells in the E2(100mg/kg),E2-b,and matrine groups were significantly decreased(P<0.01),with no significant changes in other groups(P>0.05).The proportions of CD3~+CD4~+IL-17A~+Th17 cells were not significantly different among the groups(P>0.05).Compared to the DSS model group,the proportion of CD4~+Foxp3~+Treg cells in the E2(100 mg/kg)group was increased observably(P<0.01),but there was no significant changes in other groups.(3)ELISA was used to detecte IL-6,IL-1β,TNF-αand IL-28B expression levels in colon tissue.The results showed that compared to the DSS model group,the expression levels of IL-6 in the E2(100mg/kg),E2-b,E2-a,and matrine groups were significantly decreased(P<0.05).Furthermore,the expression level of IL-1βin the E2(100mg/kg)group was significantly decreased(P<0.05),with no significant changes in the expression levels of IL-28B and TNF-αamong the groups(P>0.05).(4)Western blot was used to detecte p-STAT3,p-p65,p-IκBα,and p-p38 protein expression levels in colon tissue,The results showed that compared to the DSS model group,the expression level of p-STAT3 protein in the E2(100 mg/kg)group was significantly decreased(P<0.05),with no significant changes in the expression levels of p-p65,p-IκBα,and p-p38 proteins among the groups(P>0.05).Conclusions:(1)Water-soluble alkaloids E2 from S.moorcroftiana seeds have significant intervention effect on UC mice,the effective component of water-soluble alkaloids E2 from S.moorcroftiana seeds for UC intervention is E2-b.(2)Water-soluble alkaloids E2 from S.moorcroftiana seeds may mainly alleviate colonic inflammation in UC mice by reducing the proportion of IL-17A~+cells,increasing the proportion of CD4~+Foxp3~+Treg cells,decreasing the production of cytokines IL-6 and IL-1β,and downregulating the STAT3 signaling pathway. |
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