大鼠Kupffer细胞分泌的促炎因子在实验性急性胰腺炎肝损伤中的作用

背景：促炎因子在急性胰腺炎（AP）胰腺局部损伤以及全身炎症反应过程中起重要促进作用。目的：探讨大鼠Kupffer细胞分泌的促炎因子在实验性AP肝损伤中的作用。方法：提取24只Sprague-Dawley大鼠肝脏Kupffer细胞，并分为正常对照组、脂多糖（LPS）组、LPS＋胰弹性蛋白酶（PE）组和AG490预处理组。采用酶联免疫吸附测定（ELISA）法检测Kupffer细胞上清液中肿瘤坏死因子（TNF）-α、白细胞介素（IL）-6和IL-18含量；以细胞免疫荧光双重染色法观察细胞形态和JAK2荧光表达；以蛋白质印迹法检测JAK2蛋白表达。结果：与正常对照组相比，LPS组TNF．仅、IL-6和IL-18含量以及JAK2表达均显著增高（P〈0．01）；LPS＋PE组TNF—α、IL-6和IL-18含量以及JAK2表达显著高于LPS组（R0．01）：AG490预处理组TNF-仅、IL-6和IL—18含量以及JAK2表达显著低于LPS＋PE组（P〈0．01），但与LPS组相比无明显差异。Kupffer细胞形态改变与JAK2表达一致，Kupffer细胞胞质中JAK2荧光量、荧光强度以及蛋白表达的动态变化与TNF-α、IL-6和IL-18含量基本一致。结论：Kupffer细胞过度活化在炎症放大和AP时胰外器官损伤中起重要作用，抑制Kupffer细胞内JAK2活化可减少促炎因子的分泌．从而有效减轻AP合并的肝损伤。

Role of Proinflammatory Cytokines Secreted by Kupffer Cells on Liver Injury in Rats with Experimental Acute Pancreatitis

Background： Proinflammatory cytokines play important roles in promoting local pancreatic injury and systemic inflammatory response in acute pancreatitis （AP）. Aims： To investigate the role of proinflammatory cytokines secreted by Kupffer cells on liver injury in rats with experimental AP. Methods： Hepatic Kupffer cells were extracted from 24 Sprague-Dawley rats, and then divided into four groups： normal control group, lipopolysaccharide （LPS） group, LPS＋ pancreatic elastase （PE） group and AG490 pretreated group. The concentrations of tumor necrosis factor （TNF）-α, interleukin （IL）-6 and IL-18 in Kupffer cells supernatant were determined by enzyme-linked immunosorbent assay （ELISA）. Cell morphology and expression of JAK2 fuorescence were determined by double immunofluorescence. The expression of JAK2 protein was determined by Western blotting. Results： The concentrations of TNF-α, IL-6, IL-18 and expression of JAK2 in LPS group increased significantly than those in normal control group （P〈0.01）, but decreased significantly than those in LPS＋PE group （P〈0.01）. The concentrations of TNF-α, IL-6, IL-18 and JAK2 expression in AG490 pretreated group decreased significantly than those in LPS＋PE group （P〈0.01）, but no significant difference was found between AG490 pretreated group and LPS group. Morphological changes of Kupffer cells were consistent with JAK2 expression, and the fluorescence content, fluorescence intensity and protein expression of JAK2 in Kupffer ceils cytoplasm were dynamically consistent with changes of contents of TNF-α, IL-6 and IL-18. Conclusions： Overactivation of Kupffer cells plays an important role in the inflammation and extrapancreatic organ injury in AP, inhibition of the activation of JAK2 in Kupffer cells can reduce the secretion of proinflammatory cytokines, which may alleviate the liver injury secondary to AP.