基于RIPK1/RIPK3/MLKL信号通路探讨白头翁汤对溃疡性结肠炎小鼠肠黏膜愈合的影响

Discussion on the Effects of Baitouweng Decoction on Improving Intestinal Mucosal Healing in Mice with Ulcerative Colitis Based on RIPK1/RIPK3/MLKL Signaling Pathway

目的基于RIPK1/RIPK3/MLKL信号通路探讨白头翁汤对溃疡性结肠炎小鼠肠黏膜愈合的影响及作用机制。方法30只C57BL/6雄性小鼠随机分为对照组、模型组、白头翁汤组、英夫利西单抗组和联合组(白头翁汤+英夫利西单抗),每组6只。采用3.5%葡聚糖硫酸钠溶液自由饮用7 d建立溃疡性结肠炎小鼠模型,造模结束后,白头翁汤组每日予8 g/kg白头翁汤药液灌胃,英夫利西单抗组予5 mg/kg英夫利西单抗腹腔注射,联合组同步灌胃和腹腔注射,对照组和模型组予等体积生理盐水灌胃,连续7 d。每日记录小鼠体质量,观察粪便性状并进行疾病活动指数(DAI)评分,干预结束后测量结肠长度,ELISA检测血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)含量,HE染色观察结肠组织形态,RT-qPCR检测结肠组织受体相互作用蛋白激酶(RIPK)1、RIPK3、混合系激酶区域样蛋白(MLKL)mRNA表达,Western blot和免疫荧光染色检测结肠组织RIPK1、RIPK3、MLKL蛋白表达。结果与对照组比较,模型组小鼠体质量降低(P<0.01),DAI评分升高(P<0.01),结肠长度缩短(P<0.01),血清IL-6、TNF-α含量升高(P<0.01);结肠黏膜破坏,隐窝及腺体结构消失,大量炎性细胞浸润,结肠组织病理评分升高(P<0.01);结肠组织RIPK1、RIPK3、MLKL mRNA和蛋白表达升高(P<0.01,P<0.05)。与模型组比较,各给药组小鼠体质量增加(P<0.01),DAI评分降低(P<0.01),结肠长度增加(P<0.01),血清IL-6、TNF-α含量降低(P<0.05,P<0.01);结肠黏膜屏障破坏减轻,结肠组织病理评分降低(P<0.05);结肠组织RIPK1、RIPK3、MLKL mRNA和蛋白表达降低(P<0.05,P<0.01)。结论白头翁汤能减轻溃疡性结肠炎小鼠肠黏膜损伤、缓解炎症,其作用机制可能与抑制RIPK1/RIPK3/MLKL信号通路有关。

Objective To explore the effects and mechanism of Baitouweng Decoction in intestinal mucosal healing in mice with ulcerative colitis(UC)based on RIPK1/RIPK3/MLKL signaling pathway.Methods Totally 30 C57BL/6 male mice were randomly divided into control group,model group,Baitouweng Decoction group,infliximab group and combination group(Baitouweng Decoction+infliximab),with 6 mice in each group.A mouse model of UC was established by free administration of 3.5%sodium gluconate sulfate solution for 7 days.After modeling,Baitouweng Decoction group was given 8 g/kg Baitouweng Decoction solution by gavage daily,while the infliximab group was given 5 mg/kg infliximab intraperitoneal injection,the combination group was given synchronous gastric and intraperitoneal injection,while the control group and model group were given equal volume of normal saline by gavage for 7 consecutive days.The body mass of mice was recorded daily,fecal characteristics were observed,and disease activity index(DAI)score was performed,colon length was measured after intervention,ELISA was used to detect the contents of serum interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α),RT-qPCR was used to detect mRNA expressions of RIPK1,RIPK3 and MLKL in colon tissue,Western blot and immunofluorescence staining were used to detect the expressions of RIPK1,RIPK3 and MLKL protein in colon tissue.Results Compared with the control group,the model group mice showed a decrease in body mass(P<0.01),an increase in DAI score(P<0.01),a shortened colon length(P<0.01),and an increase in serum IL-6 and TNF-αcontent(P<0.01);colonic mucosal was destructed,with disappearance of crypts and glandular structures,extensive infiltration of inflammatory cells,and increased pathological score of colon tissue(P<0.01);the mRNA and protein expressions of RIPK1,RIPK3 and MLKL in colon tissue increased(P<0.01,P<0.05).Compared with the model group,the body mass of mice in each treatment group increased(P<0.01),and the DAI score decreased(P<0.01),colon length increased(P<0.01),and the contents of serum IL-6 and TNFαdecreased(P<0.05,P<0.01);the destruction of the colonic mucosal barrier was reduced,the pathological score of colon tissue was reduced(P<0.05);the expressions of RIPK1,RIPK3 and MLKL mRNA and protein in colon tissue decreased(P<0.05,P<0.01).Conclusion Baitouweng Decoction can alleviate intestinal mucosal damage and inflammation in UC mice,and its mechanism may be related to the inhibition of the RIPK1/RIPK3/MLKL signaling pathway.