夏枯草总三萜调控ERK、TGF-β1/Smad通路对肝纤维化大鼠的保护作用研究

摘要

Aim To investigate the protective effects of total triterpenoid from Prunella vulgaris L. ( TTP) on CCl4-induced hepatic fibrosis in rats and its mecha-nism. Methods Rat liver fibrosis was induced by 50% CCl4 twice a week for 12 weeks. From the 5th week, all the therapeutic groups were treated with the TTP(25, 50, 100 mg·kg-1 ) and the colchicine (0. 1 mg· kg-1 ) respectively once a day for 8 weeks. At the end of the twelfth week, the levels of ALT, AST, HA, PCⅢ, CⅣ, MDA, SOD, GSH-Px, Hyp were measured . HE and Masson staining were used to evalu-late the degree of hepatic fibrosis. The mRNA expres-sion ofα-SMA, procollagen I, Smad2, Smad3, Smad7 in liver was detected by RT-PCR, and the p-ERK pro-tein expression was evaluated by Western blot. Results Compared with the model group, TTP(25, 50, 100 mg·kg-1 ) not only reduced serum content of ALT, AST, HA, PCⅢ, CⅣand Hyp, MDA in liver tissue, improved the morphologic changes of hepatic fibrosis, but also increased SOD and GSH-Px activity. Moreo-ver, it decreased the α-SMA, procollagen I, Smad2, Smad3 mRNA expression and increased Smad7 mRNA expression in liver tissues obviously. Furthermore, TTP reduced the protein expression of p-ERK. Conclusions TTP can protect rats from CCl4-induced liver fibro-sis. The mechanism of this process may involve inhibi-ting the expression of p-ERK and interference with TGF-β1/Smad signal transduction pathway.%目的：研究夏枯草总三萜( TTP)对四氯化碳( CCl4)致肝纤维化大鼠的保护作用及其分子机制。方法 SD大鼠随机分为正常组、模型组、TTP(25、50、100 mg·kg-1)组和阳性对照组(秋水仙碱0．1 mg·kg-1),除正常组外,其余各组分别于大鼠背部皮下注射CCl40．1 ml·(100 g)-1,每周2次,连续12周,自造模第5周起开始给药,各给药组分别给予相应的药物,正常组、模型组给予等体积的溶媒,每天1次。实验结束后,比色法测定血清中丙氨酸氨基转氨酶( ALT)、天冬氨酸氨基转移酶( AST)含量；放免法测定透明质酸( HA)、Ⅲ型前胶原( PCⅢ)、Ⅳ型胶原( CⅣ)含量；同时取固定部位肝组织,苏木精伊红染色( HE)、Masson染色观察肝纤维化程度；制备100 g·L-1肝匀浆,进行丙二醛( MDA)、超(过)氧化物歧化酶( SOD)、谷胱甘肽过氧化物酶( GSH-Px)、羟脯氨酸( Hyp)含量测定；RT-PCR法检测α-SMA、Procollagen I、Smad2、Smad3和 Smad7 mRNA表达；Western blot法检测p-ERK蛋白表达。结果与模型组相比, TTP (25、50、100 mg ·kg-1)给药组不仅能降低肝纤维化大鼠ALT、AST、HA、CⅣ、PCⅢ、Hyp水平,改善肝脏病变程度,降低MDA水平,增强SOD以及GSH-Px活性,还可抑制肝组织中α-SMA、Pro-collagen I、Smad2、Smad3及 p-ERK 表达,升高 Smad7表达。结论夏枯草总三萜对CCl4诱导的肝纤维化大鼠具有较好的保护作用,其机制可能与下调p-ERK表达,调控TGF-β1/Smad信号通路有关。