Department of Applied Biotechnology, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, People's Republic of China.
Department of Applied Biotechnology, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, People's Republic of China.
J Ethnopharmacol. 2019 Jan 30;229:246-255. doi: 10.1016/j.jep.2018.09.041. Epub 2018 Oct 18.
Ginseng (Panax ginseng C. A. Meyer), a traditional Chinese medicine, is widely used in the adjunctive therapy of the liver diseases.
Ginsenosides are one kind of the main active ingredients in ginseng. Although hepatoprotective mechanisms of ginsenosides, such as anti-oxidation, anti-inflammation and anti-apoptosis, have been well studies, little is known about the effect of ginsenosides on drug metabolism in liver. Since CYP3A11/3A4 is a major enzyme catalyzing the drug metabolism in liver, an investigation of the enzyme's expression during the progression of a liver disease will gain valuable information about the hepatic drug metabolism. The purpose of this study was to determine the effect of ginsenosides on the expression of hepatic CYP3A11/3A4 in the lipopolysaccharides (LPS) injured human HepG2 cells and mice. We hypothesize that ginsenosides are important to stabilize CYP3A11/3A4 expression in an injured liver.
In this study, LPS was intraperitoneally intermittently injected to induce the liver injury in mice. Ginsenosides were intragastrically administered to mice for 7 days to treat the liver injury. Serum biochemical analysis and histopathological study were taken to evaluate the hepatoprotective effect of ginsenosides. The effect of ginsenosides was also evaluated in human HepG2 cells in the presence and absence of LPS. Real-time PCR and western blotting method were used to detect the mRNA and protein levels of CYP3A11/3A4 in mouse liver tissue and human HepG2 cells. The reporter gene-transfected cells were used to identify upstream targets in HepG2 cells.
LPS injection in mice resulted in the up-regulation of pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α in liver, up-regulation of hepatic enzymes such as Tbil, ALT, AST and ALP in serum, and down-regulation of CYP3A11/3A4 expression in liver. Ginsenosides treatment reversed the up-regulation of pro-inflammatory cytokines and serum hepatic enzymes elicited by LPS. Pathological results suggest that ginsenosides reduced liver damage. Moreover, ginsenosides reversed the decrease of CYP3A11/3A4 expression in the liver of LPS-injured mouse and in LPS-treated HepG2 cells. To further investigate the regulatory mechanisms, we found that ginsenosides enhanced the rifampicin-induced pregnane X receptor (PXR) transactivation of the CYP3A4 promoter. Treatment of hPXR-over-expressed cells with ginsenosides increased the rifampicin-inducible expression of CYP3A4 in a concentration-dependent manner.
Ginsenosides reverse the effects of LPS-induced hepatic CYP3A11/3A4 dysfunction, suggesting that the stabilization of the CYP3A11/3A4 expression in an injured liver appears a novel hepatoprotective mechanism of ginsenosides.
人参（Panax ginseng C. A. Meyer）是一种传统的中药，广泛用于肝脏疾病的辅助治疗。
人参皂苷是人参中的主要活性成分之一。尽管人参皂苷的抗氧化、抗炎和抗细胞凋亡等保肝机制已经得到了很好的研究，但关于其对肝脏药物代谢的影响知之甚少。由于 CYP3A11/3A4 是肝脏中主要的药物代谢酶，因此研究该酶在肝脏疾病进展过程中的表达情况将为了解肝脏的药物代谢提供有价值的信息。本研究旨在确定人参皂苷对脂多糖（LPS）损伤的人 HepG2 细胞和小鼠中肝 CYP3A11/3A4 表达的影响。我们假设人参皂苷对受损肝脏中 CYP3A11/3A4 的表达稳定具有重要意义。
本研究中，通过腹腔内间歇性注射 LPS 诱导小鼠肝损伤，并用人参皂苷灌胃治疗小鼠 7 天以治疗肝损伤。通过血清生化分析和组织病理学研究评估人参皂苷的保肝作用。还在 LPS 存在和不存在的情况下，用人 HepG2 细胞评估人参皂苷的作用。实时 PCR 和 Western blot 法检测小鼠肝组织和 HepG2 细胞中 CYP3A11/3A4 的 mRNA 和蛋白水平。使用报告基因转染细胞鉴定 HepG2 细胞中的上游靶点。
LPS 注射可导致小鼠肝脏中促炎细胞因子（如 IL-1β、IL-6 和 TNF-α）上调，血清中肝酶（如 Tbil、ALT、AST 和 ALP）上调，肝脏中 CYP3A11/3A4 表达下调。人参皂苷治疗可逆转 LPS 诱导的促炎细胞因子和血清肝酶的上调。病理结果表明，人参皂苷可减轻 LPS 损伤的肝损伤。此外，人参皂苷可逆转 LPS 损伤小鼠肝脏和 LPS 处理的 HepG2 细胞中 CYP3A11/3A4 表达的降低。为了进一步研究调节机制，我们发现人参皂苷增强了 rifampicin 诱导的 PXR（孕烷 X 受体）对 CYP3A4 启动子的转录激活。用人 PXR 过表达细胞进行处理，人参皂苷呈浓度依赖性增加 rifampicin 诱导的 CYP3A4 表达。
人参皂苷逆转了 LPS 诱导的肝 CYP3A11/3A4 功能障碍的影响，表明在受损肝脏中稳定 CYP3A11/3A4 的表达是人参皂苷的一种新的保肝机制。
