钩藤碱降低内毒素血症小鼠死亡率的机制研究

Mechanisms for a decrease in mortality of LPS-challenged mice by rhynchophylline

目的:观察钩藤碱对内毒素血症小鼠死亡率及器宫损伤的影响,并探讨其作用机制。方法:雄性小鼠随机分为对照组、脂多糖(LPS)组、钩藤碱(Rhy)防治组和Rhy对照组,分别予以生理盐水、Rhy皮下注射,1time/d,连续3d,第3d皮下注射后1h,腹腔注射生理盐水或LPS(20mg/kg)。观察各组小鼠的死亡率,肺、小肠组织病理改变;测定注射LPS后12h各组肺湿/干重比值(W/D)及血清丙氨酸氨基转移酶(ALT)、门冬氨酸氨基转移酶(AST)、尿素氮(BUN)和肌酐(Cr)的水平;用酶联免疫吸附法(ELISA)测定血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)及白细胞介素-10(IL-10)的含量,用硝酸还原酶法试剂盒测定血清一氧化氮(NO)的含量。进一步复制盲肠结扎穿孔的脓毒症模型,观察钩藤碱对脓毒症小鼠生存率的影响。结果:LPS攻击后24h小鼠的生存率明显低于对照组,8、16mg/kg的钩藤碱防治组小鼠生存率高于LPS组。但钩藤碱并不能降低CLP小鼠的死亡率,而且,8mg/kg钩藤碱治疗组小鼠的死亡率反而高于CLP小鼠的死亡率。LPS攻击后12h病理检查发现LPS组小鼠肺及小肠组织均有严重的炎症表现;肺W/D、血清ALT、AST、BUN、Cr水平显著高于对照组;LPS攻击后2h血清TNF-α、IL-1β及IL-10含量及8h血清NO水平显著高于对照组。LPS攻击后12h,Rhy防治组肺及小肠组织损伤无明显改善;肺W/D、血清ALT、AST、BUN、Cr水平与LPS组比较无显著差异;LPS攻击后2h血清TNF-α水平显著低于LPS组,但2h血清IL-1β及IL-10含量及8h血清NO水平与LPS组比较无显著差异。结论:钩藤碱能降低内毒素血症小鼠的死亡率,但不能降低脓毒症小鼠的死亡率,抑制TNF-α的生成可能是钩藤碱降低内毒素血症小鼠死亡率的机制之一。

AIM： To observe effect of rhynchophylline （Rhy） on mortality and organ injury in endotoxemic mice and further investigate the mechanisms of its actions. METHODS： Male mice were randomly assigned into control, LPS, Rhy ＋ LPS and Rhy group, and injected subcutaneously with normal saline （0.05 mL/10 g）, or rhynchophylline once a day for 3 d, 1 h after subcutaneously treatment on day 3, LPS （20 mg/kg） or normal saline was injected intraperitoneally. Survival rate was recorded every 12 h for 6 d. In another experiment, 12 h after LPS injection, the left lung and intestine tissue sections were prepared for histological analysis and the right lung were used to determine the ratio of wet to dry lung tissue weight （W/D） ,the serum was collected to detect the concentrations of alanine aminotransferase（ ALT）, aspartate aminotransferase （AST）, bloodureanitrogen （BUN） and creatinine （Cr）. In addition, the concentrations of tumor necrosis factor-a （TNF-a）, interleukin- 1β（ IL- 1β） and interleukin- 10 （IL- 10） in serum at 2 h after LPS challenge were detected by enzyme-linked immunosorbent assay. The concentration of NO in serum at 8 h was detected by enzymic method. The effect of Rhy on survival rate of mice subjected to cecal ligation and puncture （CLP） was also observed. RESULTS： Mortality of mice challenged with LPS alone was higher significantly than that in control at 24 h after LPS challenge, pretreated with Rhy at a dose of 8 or 16 mg/kg increased markedly the survival rate of LPS-challenged mice. However, Rhy at a dose of 8 mg/kg significantly increased mortality of mice subjected to CLP. In the histological analysis, severe inflammation was observed both in the lung and intestine tissues in the LPS group. LPS elevated lung W/D, the levels of ALT, AST, BUN, Cr, TNF- a, IL- 1β, IL- 10 and NO in serum. Pretreatment with Rhy had no obvious improvement in the lung and intestine tissue injury, and no significant depression in the lung W/D and the serum levels of ALT, AST, BUN, Cr, IL- 1β, IL- 10 and NO, but decreased the level of TNF -a in serum significantly in LPS -trea- ted mice. CONCLUSION： Pretreatment with Rhy reduces the mortality in endotoxemic mice, but not decrease the mortal- ity of mice challenged with CLP, at least in part, through inhibiting the synthesis and secretion of TNF - a.