广西医学

目的基于Toll样受体4（TLR4）/髓样分化因子88（MyD88）/核因子κB（NF⁃κB）信号通路探讨大黄煎剂对肝性脑病（HE）的干预作用及潜在机制。方法将20只SD大鼠随机分为空白组、模型组、乳果糖组、大黄煎剂组，每组5只。除空白组外，其余各组大鼠均持续12周皮下注射CCl4溶液，以建立HE模型。造模成功后，乳果糖组、大黄煎剂组大鼠分别予乳果糖口服液（0.167 g/kg）、大黄煎剂（7.5 g/kg）灌肠，空白组、模型组大鼠予等量生理盐水灌肠，均干预10 d。记录干预前后大鼠一般情况，采用Morris水迷宫实验、旷场实验对各组大鼠进行行为学检测。取各组大鼠肝脏组织和脑组织进行HE染色。采用ELISA法测定各组大鼠血清中ALT、AST、碱性磷酸酶（AKP）、γ⁃氨基丁酸（GABA）、谷氨酸（Glu）、5⁃羟色胺（5⁃HT）、去甲肾上腺素（NE）水平。采用FiveEasy Plus台式pH计检测结肠内容物pH值。采用Western blot和实时荧光定量PCR法检测大鼠脑组织TLR4、MyD88、NF⁃κB p65、磷酸化MyD88、磷酸化NF⁃κB p65、IL⁃6、TNF⁃α蛋白和mRNA表达水平。结果与模型组比较，乳果糖组、大黄煎剂组大鼠的肝、脑组织损伤明显改善，肝细胞和脑皮质、海马区内神经元结构较完整，炎性细胞浸润和纤维化增生程度均减轻，细胞水肿、坏死等病理损伤情况明显改善。与模型组比较，乳果糖组、大黄煎剂组大鼠的运动总距离、穿越格子次数增加，逃避潜伏期缩短，血清中ALT、AST、AKP、血氨、GABA、5⁃HT、NE水平及结肠内容物pH值均降低，Glu水平升高，且以大黄煎剂组的变化最明显（P<0.05）。与模型组比较，乳果糖组、大黄煎剂组大鼠脑组织TLR4、MyD88、NF⁃κB p65的蛋白及mRNA表达水平，磷酸化MyD88、磷酸化NF⁃κB p65的蛋白表达水平，以及IL⁃6、TNF⁃α的mRNA表达水平均降低，且大黄煎剂组的上述改变更明显（P<0.05）。结论大黄煎剂通过调控TLR4/MyD88/NF⁃κB信号通路的活化，降低血氨和肝脏炎性因子水平，纠正多种神经递质的代谢紊乱状态，从而改善HE大鼠模型的肝、脑组织炎性损伤，发挥治疗HE的作用。

Objective To explore the interventional effect and potential mechanism of Rhubarb Decoction on hepatic encephalopathy (HE) based on the Toll⁃like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF⁃κB) signaling pathway. Methods Twenty SD rats were randomly divided into blank group, model group, lactulose group, or Rhubarb Decoction group, with 5 rats in each group. Except for the blank group, rats in the remaining groups received subcutaneous injections of a CCl4 solution for 12 weeks to establish the HE model. After successful modeling, rats in the lactulose group and the Rhubarb Decoction group were administered lactulose oral solution (0.167 g/kg) and Rhubarb Decoction (7.5 g/kg) via enema, respectively, while rats in the blank and model groups received an equal volume of normal saline via enema, all for 10 days. The general condition of the rats was recorded before and after the intervention. Behavioral tests were conducted using the Morris water maze test and the open field test. Liver and brain tissues were collected from each group for hematoxylin⁃eosin (HE) staining. Serum levels of ALT, AST, alkaline phosphatase (AKP), γ⁃aminobutyric acid (GABA), glutamic acid (Glu), 5⁃hydroxytryptamine (5⁃HT), and norepinephrine (NE) were measured by ELISA. The pH value of colonic content was detected using a FiveEasy Plus benchtop pH meter. The protein and mRNA expressions of TLR4, MyD88, NF⁃κB p65, phosphorylated⁃MyD88 (p⁃MyD88), phosphorylated⁃NF⁃κB (p⁃NF⁃κB) p65, IL⁃6, and TNF⁃α in rat brain tissues were detected by Western blot and real⁃time fluorescent quantitative PCR. Results Compared with the model group, liver and brain tissue damage was significantly improved in the lactulose and Rhubarb Decoction groups. Hepatocytes and neuronal structures in the cerebral cortex and hippocampal region were more intact, the degree of inflammatory cell infiltration and fibrosis hyperplasia was reduced, and pathological damage such as cellular edema and necrosis was significantly improved. Compared with the model group, the total movement distance and number of grid crossings increased, the escape latency shortened, and levels of serum ALT, AST, AKP, blood ammonia, GABA, 5⁃HT, NE, and colonic content pH value decreased, while Glu levels increased in the lactulose and Rhubarb Decoction groups, with the changes being most pronounced in the Rhubarb Decoction group (P<0.05). Compared with the model group, the protein and mRNA expressions of TLR4, MyD88, NF⁃κB p65, the protein expressions of p⁃MyD88 and p⁃NF⁃κB p65, and the mRNA expressions of IL⁃6 and TNF⁃α in the brain tissues of the lactulose and Rhubarb Decoction groups were decreased, and these changes were more significant in the Rhubarb Decoction group (P<0.05). Conclusion Rhubarb Decoction, by regulating the activation of the TLR4/MyD88/NF⁃κB signaling pathway, reduces blood ammonia and liver inflammatory cytokine levels, corrects the metabolic disorders of various neurotransmitters, thereby ameliorating inflammatory damage in the liver and brain tissues of the HE rat model and exerting a therapeutic effect on HE.