L-theanine Prevents Alcoholic Liver Injury Through Enhancing The Antioxidant Capability Of Hepatocytes

Nowadays alcoholic liver disease (ALD) is a tough problem all around the world. The mechanism of ALD has not been revealed yet and About ALD we have no effective therapeutic regimen. Some studies indicated that ALD was associated with hepatic oxidative stress as a result of reactive oxygen species (ROS) and the generation of ROS was related to lipid peroxidation (LPO). As a key role of eliminating ROS, glutathione (GSH) is important for the redox equilibrium. The decrease of GSH indicats that a serious oxidative stress occurs. Furthermore, some intracellular antioxidant enzymes such as SOD, CAT, GR and so on contribut to maintain the level of GSH.L-theanine is a natural amino acid in green tea and is the ramification of glutamine. Though it has been proved that L-thaenine can inhibit ALD, there is no deep research about the relation between L-theanine and oxidative stress in ALD.Through the serum ALT, AST and TG examination and hematoxylin and eosin stain, this research study the biochemical and histopathologic effect of L-thaenine to ALD. Furthermore, through the hepatic MDA, GSH and antioxidant enzymes examination, this research study the effect of L-theanine in different doses to lipid peroxidation and oxidative stress.Prepared for biochenical examination, the mice were divided randomly into five groups:control group, ethanol group and three L-theanine groups. Mice in the L-theanine groups were orally administered L-theanine every day. then animals in the L-theanine groups and ethanol group were orally administered ethanol at 4 h after every administration of L-theanine.7 days later, the mice were sacrificed. Then the serum of mice was abstrcted for ALT, AST and TG examination and the liver of mice was abstrcted for hepatic MDA, GSH and antioxidant enzymes examination.Prepared for histopathology research, the mice were divided randomly into three groups:control group, ethanol group and L-theanine group. Mice in the L-theanine group were orally administered L-theanine every day. then animals in the L-theanine group and ethanol group were orally administered ethanol at 4 h after every administration of L-theanine.4 weeks later, the mice were sacrificed. Livers were prerared for HE staining and then observed. According to the level of hepatosteatosis, the livers were scored.The result is as follows:1, Ethanol could make a significant increase of serum ALT, AST and TG and L-theanine could inhibit the elevation.2, The result of paraffin section and hematoxylin and eosin stain showed that ethanol could induce a obvious hepatosteatosis but L-theanine can significantly inhibit hepatosteatosis.3, Ethanol could make a significant increase of hepatic MDA and decrease of hepatic GSH. However, L-theanine could inhibit the increase of hepatic MDA and the decrease of hepatic GSH in a dose-dependent mode.4, Ethanol could inhibit the activities of SOD, CAT and GR markedly but L-theanine could prevent the decrease of antioxidant enzymes activities.The conclusion is as follows:1, L-theanine can inhibit the increase of serum level of aminotransferase in a dose-dependent mode. And L-theanine is more effective for inhibiting the increase of serum TG, indicating maybe L-theanine pretect liver through inhibit oxidative stress induced by ROS.2, L-theanine can protect the livers of ICR mice from ethanol-induced hepatosteatosis and tissue putrescence.3, Thaenine can inhibit oxidative stress and lipid peroxidation.4, L-theanine can maintain the activities of hepatic antioxidant enzymes to hold the level of GSH, then keep the intracellular redox equilibrium. As a result oxidative stress is weaken.