雷公藤内酯醇调控GDNF、ZO-1表达对DSS诱导的小鼠结肠炎肠黏膜稳定性的影响

Triptolide regulates the expression of GDNF and ZO-1 on intestinal Mucosal Stability in DSS-induced mice Colitis

目的:探究葡聚糖硫酸钠(DSS)诱导的小鼠溃疡性结肠炎(UC)模型中胶质细胞源性神经营养因子(GDNF)、闭锁小带蛋白1(ZO-1)的表达以及雷公藤内酯醇(TL)对肠黏膜稳定性的影响。方法:将80只BALB/c雄性小鼠随机分成8组,其中10只为空白对照组(NC),其余70只饮用5%DSS溶液建立UC模型。建模第3天将70只小鼠随机分为模型组(M),丙二醇组(PG),雷公藤内酯醇低浓度组(TLL)、中浓度组(TLM)和高浓度组(TLH),地塞米松组(D),美沙拉嗪组(MS),分别给予相应药物治疗。7天后处死动物,取结肠组织进行病理学检查,采用实时定量PCR法及Western Blot法检测GDNF、ZO-1 mRNA及蛋白的表达。结果:与NC组比较,TL低中高剂量组从第4天至第7天体质量下降,但明显高于M组,差异有统计学意义(P<0.05)。病理检查显示M组小鼠肠黏膜明显受损,杯状细胞减少,出现大量炎性肉芽组织。TLM、TLH组结肠黏膜相对完整,大部分上皮细胞及腺体结构完整,极少量炎症细胞浸润,黏膜下层未见水肿。与NC组比较,模型组肠黏膜中GDNF、ZO-1 mRNA表达水平明显降低,而TLL组、TLM组、TLH组中GDNF、ZO-1 mRNA表达水平均升高,呈剂量依赖性,其中TLH组表达升高最为显著(P<0.01)。与NC组比较,模型组肠黏膜中GDNF、ZO-1蛋白表达水平明显降低,且呈剂量依赖性(P<0.05),TLL组、TLM组、TLH组中GDNF、ZO-1蛋白表达水平均升高,其中TLH组表达升高最为显著(P<0.01)。结论:雷公藤内酯醇治疗能显著减轻DSS诱导的结肠炎,可能通过增加GDNF、ZO-1的表达而保护肠黏膜结构稳定性,有望成为治疗UC的新方法。

Objective:To investigate the expression of glial cell line-derived neurotrophic factor(GDNF)and zonula occludens-1(ZO-1)and the protective effect of Triptolide(TL)on intestinal mucosal stability in mice with colitis induced by dextran sulfate sodium(DSS).Methods:80 BALB/c male mice were randomly divided into 8 groups.Among them,10 mice were breeded with normal drinking water as the negative control group(NC),and the other 70 mice were fed with 5%DSS solution to establish UC model.On the third day of DSS drinking,70 mice were randomly divided into 7 groups:model group(M),propylene glycol group(PG),triptolide low concentration group(TLL),triptolide medium concentration group(TLM),triptolide high concentration group(TLH),dexamethasone treatment group(D)and mesalazine treatment group(MS).All drugs were administrated accordingly.7 days later,the animals were sacrificed and the colon tissue was taken for pathological examination.The mRNA and protein expression of GDNF and ZO-1 in mucosa were detected by real-time quantitative PCR and Western Blot,respectively.Results:Compared with NC group,the weight of mice in TLL,TLM and TLH groups decreased from day 4 to day 7,but it was significantly higher than that in model group.In UC mice,intestinal mucosa was obviously damaged,goblet cells decreased and a large number of inflammatory granulation tissue appeared.Compared with NC group,the expression levels of GDNF and ZO-1 mRNA in model group significantly decreased,while the expression levels of GDNF and ZO-1 mRNA in TLL,TLM and TLH groups increased in a dose-dependent manner.Western Blot detection showed that the expression levels of GDNF and ZO-1 protein in model group were significantly lower than those in NC group(P<0.05).The expression levels of GDNF and ZO-1 protein in TLL,TLM and TLH groups increased as well.Conclusion:TL can alleviate DSS-induced colitis by increasing the expression of GDNF and ZO-1 and protecting the structual integrity of intestinal mucosa.It is suggested that TL may be a new drug for ulcerative colitis.