Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China; School of Pharmacy, Guangxi University of Chinese Medicine, Nanning 530200, China.
Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
Int Immunopharmacol. 2018 Mar;56:148-155. doi: 10.1016/j.intimp.2018.01.029. Epub 2018 Feb 3.
Liver fibrosis is a reversible pathophysiological process correlated with intense repair and cicatrization mechanisms, and its end-stage cirrhosis is responsible for high morbidity and mortality worldwide. Interestingly, the use of natural products as a realistic option for the treatment of liver fibrosis has broadly been accepted. Oroxylin A, a safe and natural product, shows a wide range of pharmacological activities such as anti-inflammatory, anti-oxidant, and anti-tumor properties. However, the effects of Oroxylin A on liver fibrosis remain poorly understood. In the present study, we sought to determine the effect of Oroxylin A on carbon tetrachloride (CCl)-induced liver fibrosis, and to further examine the molecular mechanisms. We found that treatment with Oroxylin A markedly decreased the level of liver injury markers, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), in a dose dependent manner. Moreover, Oroxylin A treatment remarkably inhibited extracellular matrix (ECM) deposition, and significantly down-regulated the mRNA and protein expression of liver fibrosis markers including α1(I)collagen, fibronectin, alpha-smooth muscle actin (α-SMA), PDGF-βR, and TGF-βR1 in CCl-induced murine model of liver fibrosis. Furthermore, experimental results in vitro showed that Oroxylin A treatment reduced the mRNA and protein expression of HSC activation markers, α-SMA, desmin, α1 (I) collagen, fibronectin, TGF-β, and TNF-α, in a dose dependent manner. Attractively, Oroxylin A treatment also markedly up-regulated the expression of autophagy makers, LC3-B, Atg3, Atg4, Atg5, Beclin1/Atg6, Atg7, Atg9, ATG12, and Atg14, and apparently reduced the expression of autophagy substrate p62 in both CCl-induced murine model of liver fibrosis and PDGF-BB-treated HSCs. Importantly, inhibition of autophagy by specific inhibitor 3-methyladenine (3-MA) completely abolished Oroxylin A-induced anti-fibrosis effect, indicating that activation of autophagy was required for Oroxylin A to alleviate liver fibrosis. Overall, these results provide novel implications to reveal the molecular mechanism of Oroxylin A-induced anti-fibrosis properties, by which points to the possibility of using Oroxylin A for the treatment of liver fibrosis.
肝纤维化是一种与强烈修复和瘢痕形成机制相关的可逆病理生理过程，其终末期肝硬化是全球高发病率和高死亡率的原因。有趣的是，将天然产物作为治疗肝纤维化的一种现实选择已被广泛接受。木犀草素 A 是一种安全且天然的产物，具有广泛的药理活性，如抗炎、抗氧化和抗肿瘤特性。然而，木犀草素 A 对肝纤维化的影响仍知之甚少。在本研究中，我们旨在确定木犀草素 A 对四氯化碳 (CCl) 诱导的肝纤维化的影响，并进一步研究其分子机制。我们发现，木犀草素 A 处理以剂量依赖的方式显著降低了肝损伤标志物碱性磷酸酶 (ALP)、天冬氨酸转氨酶 (AST) 和丙氨酸转氨酶 (ALT) 的水平。此外，木犀草素 A 治疗显著抑制细胞外基质 (ECM) 的沉积，并显著下调 CCl 诱导的肝纤维化小鼠模型中包括 α1(I)胶原、纤维连接蛋白、α-平滑肌肌动蛋白 (α-SMA)、血小板衍生生长因子-β受体 (PDGF-βR) 和转化生长因子-β受体 1 (TGF-βR1) 在内的肝纤维化标志物的 mRNA 和蛋白表达。此外，体外实验结果表明，木犀草素 A 处理以剂量依赖的方式降低了 HSC 激活标志物 α-SMA、结蛋白、α1 (I) 胶原、纤维连接蛋白、TGF-β 和 TNF-α 的 mRNA 和蛋白表达。吸引人的是，木犀草素 A 处理还显著上调了自噬标志物 LC3-B、Atg3、Atg4、Atg5、Beclin1/Atg6、Atg7、Atg9、ATG12 和 Atg14 的表达，并明显降低了 CCl 诱导的肝纤维化小鼠模型和 PDGF-BB 处理的 HSCs 中自噬底物 p62 的表达。重要的是，特异性自噬抑制剂 3-甲基腺嘌呤 (3-MA) 的抑制完全消除了木犀草素 A 诱导的抗纤维化作用，表明自噬的激活是木犀草素 A 减轻肝纤维化所必需的。总的来说，这些结果提供了新的意义，揭示了木犀草素 A 诱导抗纤维化特性的分子机制，这表明木犀草素 A 有可能用于治疗肝纤维化。
