Tian Xiaopeng, Zhao Huimin, Guo Zengcai
Department of Gastroenterology, Xingtai People's Hospital, Xingtai, Hebei 054000, China.
Curr Mol Med. 2020;20(9):708-716. doi: 10.2174/1566524020666200220130705.
This study was designed to investigate the effects of carvedilol on the expression of TLR4 and its downstream signaling pathway in the liver tissues of rats with cholestatic liver fibrosis and provide experimental evidence for clinical treatment of liver fibrosis with carvedilol.
A total of fifty male Sprague Dawley rats were randomly divided into five groups (10 rats per group): sham operation (SHAM) control group, bile duct ligation (BDL) model group, low-dose carvedilol treatment group (0.1mg·kg·d), medium-dose carvedilol treatment group (1mg·kg·d), and high-dose carvedilol treatment group (10mg·kg·d). Rat hepatic fibrosis model was established by applying BDL. Forty-eight hours after the operation, carvedilol was administered twice a day. The blood and liver were simultaneously collected under the aseptic condition for further detection in two weeks after the operation. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil) and albumin (Alb) in serum were measured. HE and Masson staining were used to determine hepatic fibrosis degree. Hydroxyproline assay was employed to detect liver collagen synthesis. Western Blot was used to measure the expression of TLR4, NF-κB p65 and β-arrestin2 protein. Quantitative analysis of TLR4, MyD88, TNF-α and IL-6 mRNA was performed by Realtime-PCR.
Compared with the SHAM group, the BDL group showed obvious liver injury, increased levels of inflammatory factors, and continued progression of liver fibrosis. The above changes in the BDL group were alleviated in the carvedilol treatment groups. The improvement effects augmented as dosages increased. In addition, compared with the BDL group, the reduction of the expressions of TLR4, MyD88 and NF-κB p65 in liver tissues and the increase of the expression of β -arrestin2 in the high-dose carvedilol group were more significant.
Carvedilol can reduce the release of inflammatory mediators by downregulating TLR4 expression and inhibiting its downstream signaling pathway, thus playing a potential therapeutic role in cholestatic liver fibrosis.
本研究旨在探讨卡维地洛对胆汁淤积性肝纤维化大鼠肝组织中Toll样受体4（TLR4）及其下游信号通路表达的影响，为卡维地洛临床治疗肝纤维化提供实验依据。
将50只雄性Sprague Dawley大鼠随机分为5组（每组10只）：假手术（SHAM）对照组、胆管结扎（BDL）模型组、低剂量卡维地洛治疗组（0.1mg·kg·d）、中剂量卡维地洛治疗组（1mg·kg·d）和高剂量卡维地洛治疗组（10mg·kg·d）。采用BDL法建立大鼠肝纤维化模型。术后48小时，每天给予卡维地洛2次。术后2周在无菌条件下同时采集血液和肝脏进行进一步检测。检测血清中丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、总胆红素（TBil）和白蛋白（Alb）。采用苏木精-伊红（HE）和Masson染色法确定肝纤维化程度。采用羟脯氨酸测定法检测肝脏胶原合成。采用蛋白质免疫印迹法检测TLR4、核因子κB p65（NF-κB p65）和β-抑制蛋白2（β-arrestin2）蛋白的表达。采用实时荧光定量聚合酶链反应（Realtime-PCR）对TLR4、髓样分化因子88（MyD88）、肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）mRNA进行定量分析。
与SHAM组相比，BDL组肝损伤明显，炎症因子水平升高，肝纤维化持续进展。卡维地洛治疗组减轻了BDL组的上述变化。随着剂量增加，改善效果增强。此外，与BDL组相比，高剂量卡维地洛组肝组织中TLR4、MyD88和NF-κB p65表达降低，β-arrestin2表达升高更显著。
卡维地洛可通过下调TLR4表达并抑制其下游信号通路，减少炎症介质释放，从而在胆汁淤积性肝纤维化中发挥潜在治疗作用。
