Objective: To investigate evodiamine (EVO)-induced hepatotoxicity and the underlying mechanism.
Methods: HepG2 cells were treated with EVO (0.04-25 μmol/L) for different time intervals, and the cell survival rate was examined by cell counting kit-8 (CCK-8) method. After HepG2 cells were treated with EVO (0.2, 1 and 5 μmol/L) for 48 h, the alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) activities and total bilirubin (TBIL) content of supernatant were detected. A multifunctional microplate reader was used to detect the intracellular superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in HepG2 cells to evaluate the level of cell lipid peroxidation damage. The interactions between EVO and apoptosis, autophagy or ferroptosis-associated proteins were simulated by molecular docking. The HepG2 cells were stained by mitochondrial membrane potential (MMP) fluorescent probe (JC-10) and annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI), and MMP and apoptosis in HepG2 cells were detected by flow cytometry. The protein expression levels of caspase-9, caspase-3, bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2) were detected by Western blot.
Results: The cell survival rate was significantly reduced after the HepG2 cells were exposed to EVO (0.04-25 μmol/L) in a time- and dose-dependent manner. The half maximal inhibitory concentration (IC50) of the HepG2 cells treated with EVO for 24, 48 and 72 h were 85.3, 6.6 and 4.7 μmol/L, respectively. After exposure to EVO (0.2, 1 and 5 μmol/L) for 48 h, the ALT, AST, LDH, ALP activities and TBIL content in the HepG2 cell culture supernatant, and the MDA content in the cells were increased, and SOD enzyme activity was decreased. Molecular docking results showed that EVO interacted with apoptosis-associated proteins (caspase-9 and caspase-3) better. JC-10 and Annexin V-FITC/PI staining assays demonstrated that EVO could decrease MMP and promote apoptosis in the HepG2 cells. Western blot results indicated that the protein expressions of cleaved caspase-9 and cleaved caspase-3 were upregulated in the HepG2 cell treated with EVO for 48 h. In contrast, the protein expressions of pro-caspase-3, BSEP and MRP2 were downregulated.
Conclusion: These results suggested that 0.2, 1 and 5 μmol/L EVO had the potential hepatotoxicity, and the possible mechanism involved lipid peroxidation damage, cell apoptosis, and cholestasis.
目的: 研究吴茱萸碱(evodiamine，EVO)的肝细胞毒性及其机制。
方法: 将0.04~25 μmol/L EVO分别作用于HepG2细胞24、48和72 h，用细胞增殖及毒性检测(cell counting kit-8，CCK-8)法检测细胞存活率。0.2、1和5 μmol/L EVO处理HepG2细胞48 h，多功能酶标仪分别检测细胞培养上清液中谷丙转氨酶(alanine transaminase，ALT)、谷草转氨酶(aspartate aminotransferase，AST)、乳酸脱氢酶(lactate dehydrogenase，LDH)、碱性磷酸酶(alkaline phosphatase，ALP)活性，以及总胆红素(total bilirubin，TBIL)含量。用多功能酶标仪检测HepG2细胞内超氧化物歧化酶(superoxide dismutase，SOD)活性和丙二醛(malondialdehyde，MDA)含量。用分子对接探究EVO与凋亡、自噬和铁死亡相关蛋白结合情况。用线粒体膜电位荧光探针(superior alternative to JC-1，JC-10)和异硫氰酸荧光素标记的膜联蛋白/碘化丙啶(annexin V-fluorescein isothiocyanate/propidium iodide，Annexin V-FITC/PI)对HepG2细胞进行染色，流式细胞仪分别检测细胞线粒体膜电位(mitochondrial membrane potential，MMP)和细胞凋亡。用Western blot检测HepG2细胞凋亡相关蛋白caspase-9，caspase-3以及胆汁酸转运体胆盐输出泵(bile salt export pump，BSEP)和多耐药相关蛋白2(multidrug resistance-associated protein 2，MRP2)的表达水平。
结果: 0.04~25 μmol/L EVO可降低HepG2细胞存活率，具有时间和剂量依赖关系。EVO处理HepG2细胞24、48和72 h的半数抑制浓度(half maximal inhibitory concentration，IC50)分别为85.3、6.6和4.7 μmol/L。0.2、1和5 μmol/L EVO作用HepG2细胞48 h，细胞培养上清液中ALT、AST、LDH、ALP活性升高，TBIL含量增加。EVO可降低细胞中SOD活性，增加MDA含量。分子对接结果显示EVO与凋亡相关蛋白结合情况较好，JC-10和Annexin V-FITC/PI染色发现EVO可降低MMP，增加细胞凋亡率。Western blot结果表明EVO可上调caspase-9剪切蛋白和caspase-3剪切蛋白表达，并下调caspase-3前体蛋白、BSEP和MRP2蛋白表达。
结论: 0.2、1和5 μmol/L的EVO具有肝细胞毒性，其毒性机制可能涉及脂质过氧化损伤、细胞凋亡和胆汁淤积。
Keywords: Apoptosis; Cholestasis; Evodiamine; Lipid peroxidation damage.