迷走神经兴奋对内毒素血症大鼠肝脏氧自由基及TNF-α的影响

目的探讨迷走神经兴奋与内毒素血症大鼠肝脏氧自由基和肿瘤坏因子变化的关系.方法雄性Wistar大鼠随机分为手术对照、LPS对照、迷走神经刺激和迷走神经切断后静注LPS等4组.分别测定肝组织TNF-α和丙二醛(MDA)及血浆丙氨酸氨基转移酶(ALT)的含量.结果假手术组TNF含量较低,静注LPS后,TNF含量明显升高;迷走神经刺激组TNF含量较单纯LPS组和迷走神经切断后注射LPS组明显降低;迷走神经刺激组血浆ALT含量及肝组织MDA含量显著低于单纯LPS组和迷走神经切断后静注LPS组(P＜0.01).结论迷走神经兴奋能显著降低内毒素血症大鼠体内促炎细胞因子的产生,减缓体内氧自由基的释放,对肝组织具有潜在的保护作用.

EFFECTS OF ELECTRICAL STIMULATION OF VAGUS NERVE ON LEVELS OF MALONDIALDEHYDE AND TNF-α IN RATS WITH ENDOTOXEMIA

Objective:To investigate the relationship between the electrical stimulation of vagus nerve and changes of liver malondialdehyde(MDA) and tumor necrosis factor-α(TNF-α) in rats with endotoxemia.Methods:Wistar rats were subjected to bilateral cervical vagotomy. The distal end of the vagus nerve trunk was placed across bipolar electrodes connected to a stimulation module with acquisition system control. Constant voltage stimuli (5 v, 2 ms, 1 hz) were applied to the nerve for 20 min immediately after administration of LPS, and then repeated twice at an interval of 10 min. The level of alanine aminotransferase(ALT) in plasma and the levels of TNF-α and MDA in liver were determined at 1 h, 1.5 h and 2 h after LPS challenge.Results:The hepatic TNF-α levels in endotoxin challenged rats were significantly higher than those in the sham controls. Compared to animals receiving no electrical stimulation, electrical stimulation of the efferent vagus nerve significantly decreased the hepatic contents of TNF-α, MDA and plasma ALT levels in endotoxin challenged rats.Conclusions:Excitation of the efferent vagus nerve could significantly reduce the production of the proinflammatory cytokine and alleviate the release of oxygen-derived free radicals after endotoxin challenge. The results suggested that excitation of vagus nerve might have potential protective effect on liver.