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

以大鼠肝脏灌流为体外系统，研究了肝交感神经在急性肝损伤中的作用及细胞因子的参与。结果如下：1)肝神经刺激对急性肝损伤的影响：D-氨基半乳糖处理后，大鼠肝脏原位灌流，无再循环，造成急性肝损伤。测定流出液中乳酸脱氢酶和天冬氨酸氨基转移酶的活性作为急性细胞损伤的标志，电刺激肝神经使这些酶的漏出量增加。此外，将枯否细胞的激活剂酵母多糖注入门静脉也增加了酶的渗漏，就像神经刺激一样。这些结果表明，肝神经的激活加重了急性肝损伤，肝非实质细胞可能参与了肝神经的作用。2)神经刺激时去甲肾上腺素的溢出和受体亚型：in…上述肝脏灌流越多，去甲肾上腺素在神经刺激过程中流出的流出物迅速增加，表明这些神经属于交感神经系统。另一方面，α-肾上腺素能阻滞剂盐酸巴那唑嗪能显著抑制刺激肝神经引起的急性肝损伤，提示肝交感神经的作用主要是由α-肾上腺素能受体介导的。3)灌流肝脏产生肿瘤坏死因子-α的生物测定：利用WEHI164细胞克隆建立了与肝细胞死亡相关的肿瘤坏死因子-α的生物测定系统。半乳糖胺处理的肝脏流出物中的肿瘤坏死因子-α活性高于正常肝脏。此外，电刺激肝交感神经可迅速增加氨基半乳糖处理后肝脏的肿瘤坏死因子-α的产量。4)肝组织中肿瘤坏死因子的免疫组织化学：用抗肿瘤坏死因子-α抗体对肝组织中肿瘤坏死因子-α进行免疫组织化学研究，结果显示，半乳糖胺处理的肝组织中肿瘤坏死因子-α表达较强，提示肝损伤时该细胞因子的产生增加。这些结果表明，肝交感神经的激活加剧了肝损伤，肝脏肿瘤坏死因子在肝神经的作用中起重要作用。较少

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