急性胰腺炎大鼠脑组织TNF-α mRNA和蛋白表达及其意义

Expression and significance of TNF-α and proteins in cerebral tissue of rats with acute necrotizing pancreatitis KONG Lei, HAN Tian-quan, FENG Dian-xu, et al（ Department of Surgery, Ruijin Hospital, Medical College of Shanghai J iaotong University, Shanghai 200062, P. R. China）

目的探讨急性胰腺炎大鼠脑组织中TNF-α mRNA和蛋白的表达及其对胰性脑病发病机制的意义。方法应用5％、1％的牛磺胆酸钠分别诱导急性坏死性胰腺炎（ANP）和急性水肿性胰腺炎（AEP）大鼠模型，同时设立假手术组，每组16只。分别于模型诱导后12h，以酶联免疫吸附（ELISA）法测定大鼠血液和脑脊液标本中TNF-α的含量，RT-PCR方法测定脑组织TNF-α mRNA的表达，Western-Blot测定TNF-α蛋白的表达水平，免疫组化观察TNF-α蛋白的定位表达。结果ANP组、AEP组和假手术组的血清TNF-α水平分别为1065．6pg／ml、577．5pg／ml和543．8pg／ml，脑脊液TNF-α水平分别为820．9pg／ml、307．4pg／ml和481．6pg／ml。ANP组血清和脑脊液TNF-α水平同AEP组和假手术组相比，差异均有显著性（P〈0．05）。ANP组脑组织TNF-α mRNA和蛋白的表达明显增强。ANP组TNF-α蛋白的表达定位于大脑小胶质细胞和神经元细胞。结论在ANP病程中，大鼠脑组织可能是细胞因子过度表达的来源之一；脑组织中，TNF-α主要由小胶质细胞和神经元细胞表达；TNF-α的过度表达可能是ANP早期脑髓鞘损伤的原因之一。

Objective To investigate the expression of TNF-α messenger RNA （mRNA） and peptide in the brain of rats with acute pancreatitis （AP） and explore its significance in the pathogenesis of pancreatic encephalopathy （PE）. Methods Models of acute necrotizing pancreatitis （ANP, n= 16） and acute edematous pancreatitis （AEP, n= 16） were induced by injecting sodium taurocholate into the pancreatic duct of male Sprague-Dawley rats. Another 16 normal rats were employed to serve as controls. Twelve hours after the induction of AP, the rats in each group were sacrificed and the blood and cerebral spinal fluid （CSF） samples were taken for determining the level of TNF-α by ELISA. TNF-α mRNA and peptide expression in the cerebral tissues was assessed by semiquantitative RT-PCR, Western blotting and immunohistochemistry, respectively. Results TNF-α concentration in blood and CSF of rats with ANP showed significant elevation as compared with AEP and control group （P〈 0.05）. TNF-α concentration in blood of ANP, AEP and control group were 1065. 6 pg/ml, 577. 5 pg/ml and 543.8 pg/ml, respectively. The concentration in CSF was 820.9 pg/ml, 307.4 pg/ml and 481.6 pg/ml, respectively. TNF-α mRNA expression and its protein level in the cerebra of rats with ANP were significantly greater than that in the other two groups respectively （P〈0.05）. Double-labeling and immunohistochemical studies revealed that the protein was located in the microglial cells and neurons in the cerebrum. Conclusion The cerebrum might be one of the organs releasing cytokines during AP. TNF-α is overproduced by both microglial cells and neurons in the cerebrum and might play an important role in the demyelinization of brain during the early stage of ANP.