灵杆菌多糖对内毒素所致小鼠休克死亡的保护作用及其机制研究

Experimental study of hemarisin in protecting mice from lethal endotoxin shock and inhibiting production of proinflammatory cytokines

目的探讨灵杆菌多糖对内毒素所致小鼠休克死亡的保护作用及其机制。方法昆明小鼠分别腹腔注射铜绿假单胞菌脂多糖(内毒素)60mg/kg或10mg/kg制作内毒素中毒休克死亡模型和内毒素血症模型,灵杆菌多糖提前0.5h预防性腹腔注射给药,观察内毒素中毒休克死亡模型动物3d内的死亡情况,以及内毒素血症模型动物3h后血清中细胞因子IL-1β、IL-6、TNF-α含量的变化。以内毒素(10μg/ml)体外刺激小鼠腹腔渗出细胞,观察灵杆菌多糖对内毒素诱导IL-1β、IL-6、TNF-α表达的抑制作用。细胞因子含量的检测采用ELISA法。结果内毒素中毒休克死亡模型中,灵杆菌多糖(50、100U/kg)预处理动物的存活率(70%、55%)明显高于未经预处理者(10%,P<0.01);同样剂量下,灵杆菌多糖可明显抑制内毒素血症模型小鼠血清IL-1β、IL-6、TNF-α含量的升高(P<0.05)。体外实验显示,20U/ml灵杆菌多糖可轻微刺激小鼠腹腔渗出细胞分泌IL-1β、IL-6、TNF-α(P<0.05),而10U/ml及20U/ml灵杆菌多糖可明显抑制由内毒素诱导的小鼠腹腔渗出细胞IL-1β、IL-6、TNF-α的分泌(P<0.05)。结论灵杆菌多糖本身可轻微促进IL-1β、IL-6、TNF-α的分泌,但与内毒素同时存在时可抑制后者刺激促炎细胞因子分泌的作用并拮抗后者的毒性作用。

Objective To investigate the effects of hemarisin（lipopolysaccharide from Bacillus prodigiosus） on protecting mice from lethal endotoxin shock,and explore the underlying mechanism of action.Methods Models of lethal endotoxin shock and endotoximia were reproduced in KM mice by intraperitoneal（ip） administration of lipopolysaccharides（endotoxin） from Pseudomonas aeruginosa in doses of 60mg/kg or 10mg/kg respectively.Exudate cells from peritoneal carity activated by endotoxin were used as in vitro inflammatory cell model.Levels of interleukin-1β（IL-1β）,interleukin-6（IL-6） and tumor necrosis factor-α（TNF-α） were measured by enzyme-linked immunosorbent assay（ELISA）.Results The survival rate was found to be higher in mice prophylactically treated with 100 or 50 U/kg hemarisin（0.5h before endotoxin administration）（70% and 55%） than in model group（10%,P0.01）.The serum levels of IL-1β,IL-6 and TNF-α were significantly lower in 100 or 50 U/kg hemarisin-treated mice（0.5h before endotoxin administration） than in model groups（P0.05）.Hemarisin（20U/mL） alone showed slight stimulatory effect to peritoneal exudate cells in producing IL-1β,IL-6 and TNF-α in vitro（P0.05）.When used in combination with endotoxin,however,hemarisin（20 and 10 U/mL） showed antagonistic effect against endotoxin in inducing the secretion of IL-1β,IL-6 and TNF-α in vitro（P0.05）.Conclusions Hemarisin shows a slight promotive effect on production of IL-1β,IL-6 and TNF-α when it is used alone.When used in combination with endotoxin,however,hemarisin may inhibit endotoxin from stimulating the production of proinflammatory cytokines and antagonize the endotoxin toxicity.