title: Protective effect of L-theanine on carbon tetrachloride-induced acute liver injury in mice.
abstract: We studied effects of L-theanine, a unique amino acid in tea, on carbon tetrachloride (CCl(4))-induced liver injury in mice. The mice were pre-treated orally with L-theanine (50, 100 or 200 mg/kg) once daily for seven days before CCl(4) (10 ml/kg of 0.2% CCl(4) solution in olive oil) injection. L-theanine dose-dependently suppressed the increase of serum activity of ALT and AST and bilirubin level as well as liver histopathological changes induced by CCl(4) in mice. L-theanine significantly prevented CCl(4)-induced production of lipid peroxidation and decrease of hepatic GSH content and antioxidant enzymes activities. Our further studies demonstrated that L-theanine inhibited metabolic activation of CCl(4) through down-regulating cytochrome P450 2E1 (CYP2E1). As a consequence, L-theanine inhibited oxidative stress-mediated inflammatory response which included the increase of TNF-α and IL-1β in sera, and expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in livers. CCl(4)-induced activation of apoptotic related proteins including caspase-3 and PARP in mouse livers was also prevented by L-theanine treatment. In summary, L-theanine protects mice against CCl(4)-induced acute liver injury through inhibiting metabolic activation of CCl(4) and preventing CCl(4)-induced reduction of anti-oxidant capacity in mouse livers to relieve inflammatory response and hepatocyte apoptosis.
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Min
authors.initials: M
authors.lastname: Gao
authors.forename: Shuai
authors.initials: S
authors.lastname: Sun
authors.forename: Aijing
authors.initials: A
authors.lastname: Bi
authors.forename: Yinqiang
authors.initials: Y
authors.lastname: Xin
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Han
authors.forename: Liangbin
authors.initials: L
authors.lastname: Wang
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Yin
authors.forename: Lan
authors.initials: L
authors.lastname: Luo
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D002251:Carbon Tetrachloride / Q000037:antagonists & inhibitors* / Q000633:toxicity; D002252:Carbon Tetrachloride Poisoning / Q000517:prevention & control*; D051546:Cyclooxygenase 2; D019392:Cytochrome P-450 CYP2E1 / Q000096:biosynthesis; D005971:Glutamates / Q000008:administration & dosage*; D005978:Glutathione; D022781:Hepatocytes / Q000187:drug effects; D053583:Interleukin-1beta / Q000097:blood; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000473:pathology; D017114:Liver Failure, Acute / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018384:Oxidative Stress / Q000187:drug effects; D020011:Protective Agents / Q000008:administration & dosage*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D000975:Antioxidants; D005971:Glutamates; D053583:Interleukin-1beta; D020011:Protective Agents; D014409:Tumor Necrosis Factor-alpha; C026166:theanine; D002251:Carbon Tetrachloride; D019392:Cytochrome P-450 CYP2E1; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D005978:Glutathione