Mechanism of hepatic sympathetic action on potentiating liver injury and the involvement of cytokines.

本实验以离体大鼠肝脏为研究对象，研究了肝交感神经对急性肝损伤的影响及细胞因子的参与，结果如下：1）肝神经刺激对急性肝损伤的影响：大鼠肝脏经D-氨基半乳糖处理后，原位恒压无再循环灌注，造成急性肝损伤。测定流出液中乳酸脱氢酶和天冬氨酸转氨酶的活性作为急性细胞损伤的标志物，电刺激肝神经增加了这些酶的泄漏。此外，输注酵母聚糖，枯否细胞的激活剂，到门静脉也增加了酶的泄漏，像神经刺激。提示肝神经的激活可加重急性肝损伤，肝非实质细胞可能参与肝神经的活动。2）神经刺激时去甲肾上腺素溢出及受体亚型：In ...更多信息 在上述灌注的肝脏中，在神经刺激期间，溢出到流出物中的去甲肾上腺素迅速增加，表明这些神经属于交感神经系统。另一方面，α-肾上腺素能阻断剂盐酸布那唑嗪显著抑制由肝神经刺激引起的急性肝损伤的增强，表明肝交感神经的作用主要由α-肾上腺素能受体介导。3）灌注肝脏的TNF-α输出的生物测定：用WEHI 164细胞克隆建立了与肝细胞死亡相关的肿瘤坏死因子-α（TNF-α）的生物测定体系。半乳糖胺处理的肝脏中流出物中的TNF-α活性高于正常肝脏。此外，电刺激肝交感神经可迅速增加半乳糖胺处理的肝脏中TNF-α的输出。这些结果表明，TNF-α的产生和释放在损伤的肝脏中增加并受肝交感神经调节，并且枯否细胞对TNF-α的产生很重要。4）肝脏中TNF-α的免疫组织化学：使用抗TNF-α抗体对肝脏中TNF-α进行的免疫组织化学显示，TNF-α在半乳糖胺中被强烈染色。这些结果表明肝交感神经的激活增强了肝损伤，并且肝TNF-α在肝神经的作用中具有重要作用。少

The effects of hepatic sympathetic nerves on acute liver damage and the involvement of cytokine were studied using perfused rat liver as ex vivo system.The results were as follows :1) Effects of hepatic nerve stimulation on acute liver damage : Rat livers were perfused in situ without recirculation under constant pressure after treatment with D-galactosamine to produce acute liver injury. Meassuring the activities of lactate dehydrogenase and aspartate aminotransferase in the effluent as markers of acute cell damage, electrical stimulation of hepatic nerves increased the leakage of these enzymes. Moreover, infusion of zymosan, an activator of kupffer cells, into the portal vein also increased the enzyme leakage like nerve stimulation. These result indicate that the activation of hepatic nerves potentiates acute liver injury and that hepatic non-parenchymal cells may be involved in the action of hepatic nerves.2) Noradrenaline overflow during nerve stimulation and receptor subtype : In … More perfused livers described above, noradrenaline overflow into the effluent was rapidly increased during nerve stimulation indicating that these nerves belong to sympathetic nervous system. On the other hand, the potentiation of acute liver damage caused by hepatic nerve stimulation was significantly inhibited by alpha-adrenergic blocker bunazosin hydrochloride, suggesting that the effects of hepatic sympathetic nerves are mainly mediated by alpha-adrenergic receptors.3) Bioassay of TNF-alpha output from perfused liver : Bioassy system of Tumor Necrosis Factor-alpha (TNF-alpha), Which is related with cell death of hepatocyte, was established using WEHI164-cell clone. TNF-alpha activity in the effluent was higher in galactosamine-treated liver than in normal liver. Moreover, electrical stimuration of hepatic sympathetic nerves rapidly increased TNF-alpha output in galactosamine-treated liver. These results suggest that production and release of TNF-alpha is increased in injured livers and regulated by hepatic sympathetic nerves, and that Kupffer cell is important for TNF-alpha production.4) Immunohistochemistry of TNF-alpha in the liver : Immunohistochemistry of TNF-alpha in the liver using anti-TNF-alpha antibodies showed that TNF-alpha was strongly stained in galactosamine-treated liver suggesting the increased production of this cytokine in injured liver.These results indicate that the activation of hepatic sympathetic nerves potentiates liver injury and that hepatic TNF-alpha has an important role in the action of hepatic nerves. Less