l-Theanine prevents alcoholic liver injury through enhancing the antioxidant capability of hepatocytes.
l-Theanine is a unique amino acid in green tea. We here evaluated the protective effects of l-theanine on ethanol-induced liver injury in vitro and in vivo. Our results revealed that l-theanine significantly protected hepatocytes against ethanol-induced cell cytotoxicity which displayed by decrease of viability and increase of LDH and AST. Furthermore, the experiments of DAPI staining, pro-caspase3 level and PARP cleavage determination indicated that l-theanine inhibited ethanol-induced L02 cell apoptosis. Mechanically, l-theanine inhibited loss of mitochondrial membrane potential and prevented cytochrome c release from mitochondria in ethanol-treated L02 cells. l-Theanine also prevented ethanol-triggered ROS and MDA generation in L02 cells. l-Theanine restored the antioxidant capability of hepatocytes including GSH content and SOD activity which were reduced by ethanol. In vivo experiments showed that l-theanine significantly inhibited ethanol-stimulated the increase of ALT, AST, TG and MDA in mice. Histopathological examination demonstrated that l-theanine pretreated to mice apparently diminished ethanol-induced fat droplets. In accordance with the in vitro study, l-theanine significantly inhibited ethanol-induced reduction of mouse antioxidant capability which included the activities of SOD, CAT and GR, and level of GSH. These results indicated that l-theanine prevented ethanol-induced liver injury through enhancing hepatocyte antioxidant abilities.
Jiangsu Province Key Laboratory for Molecular and Medicine Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210046, People's Republic of China.
Guilan
G
Li
Yin
Y
Ye
Jingjing
J
Kang
Xiangyang
X
Yao
Yizhou
Y
Zhang
Wei
W
Jiang
Min
M
Gao
Yudong
Y
Dai
Yinqiang
Y
Xin
Qi
Q
Wang
Zhimin
Z
Yin
Lan
L
Luo
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D005971:Glutamates / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008108:Liver Diseases, Alcoholic / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR
D000975:Antioxidants; D005971:Glutamates; C026166:theanine