烟碱对腹腔感染败血症小鼠的保护作用及其机制研究

Protective effect of nicotine against septicemia in mice after cecal ligation and puncture

目的探讨烟碱激活胆碱能抗炎通路对败血症的保护作用及其机制。方法采用盲肠结扎并穿孔(CLP)法复制败血症模型。65只健康昆明小鼠分为对照组、CLP组和烟碱400μg/kg组,记录CLP后24、36和48 h的生存率。另取18只小鼠分组同上,CLP后20 h计算肺湿干重比、败血症严重程度评分,行肝、肺组织病理学检查。另取120只小鼠随机分为对照组、CLP组,以及烟碱400、200和40μg/kg组,酶联免疫吸附法检测CLP后1、2、4和6 h血浆TNF-α和IL-1β的浓度。结果术后24、36和48 h,烟碱400μg/kg组生存率较CLP组升高(P<0.05);术后20 h烟碱400μg/kg组肺湿干重比和败血症严重程度评分较CLP组降低(P<0.05),肝、肺组织病理改变较CLP组减轻。术后2、4和6 h,烟碱400、200和40μg/kg组血浆TNF-α浓度较CLP组降低(P<0.05);术后1和6 h,烟碱400、200和40μg/kg组血浆IL-1β浓度较CLP组降低(P<0.05)。烟碱400μg/kg组血浆TNF-α浓度在术后2 h低于40μg/kg组(P<0.05),术后6 h低于200和40μg/kg组(P<0.05)。并术后2和4 h烟碱200μg/kg组血浆TNF-α浓度较40μg/kg组降低(P<0.05)。术后4 h烟碱400μg/kg组血浆IL-1β浓度低于200和40μg/kg组(P<0.05)。结论烟碱减轻腹腔严重感染小鼠败血症严重程度,改善肝、肺的病理组织学变化,降低机体促炎症细胞因子水平,提高生存率。

Objective To investigate whether nicotine,a nicotinic acetylcholine receptor(nAChR)agonist,has protective effect on septicemia.Methods A septicemia model was induced by cecal ligation and puncture(CLP).Totally 65 female mice were randomly divided into 3 groups.The control group(15 mice)received sham operation,the CLP group(20 mice)received cecal ligation and puncture(CLP),and the mice in nicotine group(30 mice)were intraperitoneally injected with 400μg/kg nicotine 30 min before CLP.The survival rates were recorded 24,36 and 48 h after CLP.Additional 18 female mice were grouped according to the same method as above;at the 20th h after operation,the septicemia severity score and the lung wet/dry weight ratio were evaluated and the liver and the lungs were histopathologically examined.Still 120 more female mice were randomly divided into 5 groups,i.e.control group,CLP group,nicotine 400μg/kg group,nicotine 200μg/kg group and nicotine 40μg/kg group.The mice were sacrificed at the 1st,2nd,4th and 6th h after CLP.The plasma concentrations of proinflammatory cytokines including tumor necrosis factor alpha(TNF-α)and interleukine 1 beta(IL-1β)were measured using ELISA.Results At the 24th,36th and 48th h after CLP,the survival rate of the nicotine 400μg/kg group was significantly higher than that of the CLP group(P<0.05).At the 20th h after CLP,the septicemia severity score and the lung wet/dry weight ratio significantly decreased in the nicotine 400μg/kg group compared with the CLP group(P<0.05),the pathological changes of the liver and the lungs were ameliorated compared to the CLP group.At the 2nd,4th and 6th h after CLP,the plasma levels of TNF-αin the the nicotine 400,200 and 40μg/kg groups were lower than those of the CLP group(P<0.05).The plasma level of TNF-αin the the nicotine 400μg/kg group was lower than that of the nicotine 40μg/kg group 2 h after CLP(P<0.05),and lower than those of the nicotine 200 and 40μg/kg groups 6 h after CLP(P<0.05).The plasma level of TNF-αin the the nicotine 200μg/kg group was lower than that of the nicotine 40μg/kg group 2 and 4 h after CLP(P<0.05).At the 1st and 6th h after CLP,the plasma IL-1βlevels of the nicotine 400,200 and 40μg/kg groups were lower than that of the CLP group(P<0.05).At the 4th h aftr CLP,the plasma IL-1βlevel of the nicotine 400μg/kg group was lower than those of the nicotine 200 and 40μg/kg groups(P<0.05).Conclusions Nicotine has protective effects against septicemia in mice through activation of the cholinergic anti-inflammatory pathway to inhibit production of inflammatory cytokines.