溃结康对溃疡性结肠炎小鼠NLRP3炎性体基因表达及下游炎性因子影响

Study on Influence of Kuijiekang Decoction on NLRP3 Inflammasome and Its Downstream Inflammatory Cytokines in Mice with Ulcerative Colitis

目的探讨溃结康对溃疡性结肠炎小鼠NLRP3炎性体及下游炎性因子的影响。方法建立葡聚糖硫酸钠诱导小鼠实验性溃疡性结肠炎(急性期、缓解期)模型,实验分为正常对照组、模型组、柳氮磺胺吡啶组(0.45 g/kg)、溃结康(12.8、6.4、3.2 g/kg)组。第8天(急性期)及第21天(缓解期)实验结束时,采集结肠组织,量取各组小鼠结肠长度,HE染色观察小鼠结肠病理变化,免疫组化染色法检测结肠组织MPO表达,酶联免疫法检测结肠组织IL-18、IL-33含量变化,实时荧光定量PCR检测结肠NLRP3、ASC、Caspase-1mRNA表达。结果模型组单位结肠长度显著缩短,结肠组织损伤明显,MPO表达显著增加,结肠IL-18,IL-33水平明显升高,NLRP3、ASC、Caspase-1mRNA表达显著上调(P<0.05或P<0.01);与模型组比较,急性期时,柳氮磺胺吡啶组及溃结康高剂量组单位结肠长度明显增加,MPO表达显著降低,IL-18释放减少,NLRP3及Caspase-1mRNA表达显著下调(P<0.05或P<0.01),同时,溃结康中剂量组IL-18水平也显著降低,NLRP3 mRNA显著下调(P<0.05);溃结康低剂量组Caspase-1mRNA表达明显降低(P<0.05)。缓解期时,柳氮磺胺吡啶组及溃结康高、中剂量组单位结肠长度均明显增加(P<0.05或P<0.01);溃结康高剂量组NLRP3及Caspase-1mRNA表达显著增加,溃结康中剂量组IL18、IL-33含量明显增加,ASC、Caspase-1mRNA表达明显上调,低剂量组IL-33含量也明显增加(P<0.05),NLRP3 mRNA表达上调(P<0.05或P<0.01)。结论溃结康可能通过调节UC小鼠发病不同时期(急性期、缓解期)NLRP3炎性体(NLRP3、ASC、Caspase-1)基因表达及下游炎症因子的释放抑制炎症反应,促进缓解期时结肠黏膜修复。

Objective To investigate the therapeutic effects of Kuijiekang Decoction(KJKD) on NLRP3 inflammasome and its downstream inflammatory cytokines in the treatment of mice with ulcerative colitis. Methods The animal model of ulcerative colitis induced by dextran sodium sulfate(DSS) was established. The experimental animals were divided into blank control group,the model group,SASP group(0.45 g/kg) and KJKD high dose(12.8 g/kg),medium dose(6.4 g/kg),low dose(3.2 g/kg) groups. 8 days(acute stage) and 21 days(remission stage) after treatment,the mice were killed to collect colonic mucosa, the therapeutic effect was evaluated with the length of colon/body weight. The pathological changes of colon were observed under light microscope by HE colouring method. The expressions of MPO in colon tissue were measured by immunohistochemical staining. The contents of IL-18 and IL-33 were observed by ELISA method. The expressions of NLRP3,ASC and Caspase-1 mRNA were detected by realtime polymerase chain reaction(RT-PCR). Results Compared with those of the normal group,the colonic length/body weight was reduced and the injury of colonic tissue was serious. The expression of MPO,the contents of IL-18 and IL-33 and the expressions of NLRP3,ASC and Caspase-1 mRNA were significantly increased(P<0.05 or P<0.01). Compared with those of the model group, at the acute stage,the colonic length/body weight was improved. The expression of MPO as well as the content of IL-18,gene expressions of NLRP3 and Caspase-1 mRNA were decreased significantly(P<0.05 or P<0.01)in SASP group and high dose group of KJKD. Meanwhile,the levels of IL-18 and NLRP3 mRNA were lower(P<0.05) in KJKD middle and low dose groups and Caspase-1 mRNA in the KJKD low dose group was decreased(P<0.05). At the remission stage, the colonic length/body weight was improved in SASP group and KJKD high and middle dose groups(P<0.05 or P<0.01)and meanwhile NLRP3 and Caspase-1 mRNA in high dose group were up-regulated. The levels of IL18 and IL-33 and the expressions of ASC and Caspase-1 mRNA in KJKD middle dose group were higher than those in the model group and at the same time KJKD low dose group could also up-regulate the the expressions of IL-33 and NLRP3 mRNA(P<0.05 or P<0.01). Conclusion KJKD ameliorates DSS-induced ulcerative colitis in mice might through regulating the expressions of NLRP3 inflammasome and its downstream inflammatory cytokines in different stages of UC to inhibit inflammation and promote repair of colon tissue.