Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, Liaoning, PR China.
Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, Liaoning, PR China; Department of Chemistry and Life Science, School of Advanced Engineering, Kogakuin University, 2665-1, Nakanomachi, Hachioji, Tokyo 192-0015, Japan; Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017, Japan.
Toxicol In Vitro. 2021 Feb;70:105047. doi: 10.1016/j.tiv.2020.105047. Epub 2020 Oct 30.
Silibinin, one of the flavonoids isolated from milk thistle seeds of Silybum marianum, has hepatoprotective properties against toxins in clinical. However, the detailed mechanisms have remained unclear. This study investigates the underlying mechanism of silibinin in the protection against ethanol- or acetaldehyde-induced damage of neonatal mouse primary hepatocytes in vitro. The results show that ethanol inhibited proliferation of hepatocytes in a time (12, 24, 36 h) and dose-dependent (0-800 mM) manner. However, silibinin did not show protective effect on ethanol (500 mM)-induced suppression of hepatocyte proliferation. Acetaldehyde, the toxic metabolite of ethanol, appearing immediately in individuals after drink also inhibited the proliferation of hepatocytes in a dose-dependent (0-12 mM) manner. Surprisingly, silibinin significantly increased the cell viability and reduced the leakage of alanine amino transferase (ALT) and aspartate amino transferase (AST) in acetaldehyde-treated hepatocytes, suggesting that silibinin protected cell injury caused by acetaldehyde treatment. The apoptosis-inducing effect of acetaldehyde was demonstrated by the increased number of cells in sub-G1 phase as well as caspase-3 activation. Further study shows that acetaldehyde induced autophagy in the hepatocytes. The autophagy inhibitors, 3-Methyladenine (3-MA) and chloroquine (CQ), further decreased the viability of cells treated with acetaldehyde, suggesting that autophagy plays a protective role against apoptosis. Consistently, silibinin (20 μM) significantly reduced the activation of caspase 3 or apoptosis and increased the conversion of LC3-I to LC3-II or autophagy. Taken together, it is concluded that silibinin does not repress the ethanol- induced hepatocyte injury, whereas silibinin reduces acetaldehyde-caused hepatocyte injury through down-regulation of apoptosis and up-regulation of autophagy.
水飞蓟宾是从水飞蓟种子中分离得到的一种黄酮类化合物，具有护肝作用，可对抗临床毒素。然而，其详细机制尚不清楚。本研究旨在探讨水飞蓟宾对体外乙醇或乙醛诱导的新生鼠原代肝细胞损伤的保护作用机制。结果表明，乙醇呈时间（12、24、36 h）和剂量（0-800 mM）依赖性抑制肝细胞增殖。然而，水飞蓟宾对乙醇（500 mM）诱导的肝细胞增殖抑制没有保护作用。乙醛是乙醇的有毒代谢物，人饮酒后立即出现，也呈剂量依赖性（0-12 mM）抑制肝细胞增殖。令人惊讶的是，水飞蓟宾显著增加了乙醛处理肝细胞的细胞活力，降低了丙氨酸氨基转移酶（ALT）和天冬氨酸氨基转移酶（AST）的漏出，表明水飞蓟宾可减轻乙醛处理引起的细胞损伤。乙醛诱导的细胞凋亡作用通过增加细胞亚 G1 期数量和激活半胱氨酸天冬氨酸蛋白酶-3（caspase-3）来证明。进一步的研究表明，乙醛诱导肝细胞自噬。自噬抑制剂 3-甲基腺嘌呤（3-MA）和氯喹（CQ）进一步降低了乙醛处理细胞的活力，表明自噬对细胞凋亡起保护作用。一致地，水飞蓟宾（20 μM）显著降低了 caspase-3 或凋亡的激活，并增加了 LC3-I 向 LC3-II 或自噬的转化。总之，水飞蓟宾不会抑制乙醇诱导的肝细胞损伤，而水飞蓟宾通过下调凋亡和上调自噬来减轻乙醛引起的肝细胞损伤。
