Protective effect of lactobacillus plantarum on alcoholic liver injury and regulating of keap-Nrf2-ARE signaling pathway in zebrafish larvae

This research investigated the protective effect of lactobacillus plantarum against alcohol-induced liver injury and the regulatory mechanism of Keap-Nrf2-ARE signal pathway in zebrafish. Firstly, a zebrafish alcoholic liver injury model was established using1.0mM of ethanol concentration, then two forms of lactobacillus plantarum treatment were designed to perform repair, including a lactobacillus plantarum thallus suspension (LPS) and a lactobacillus plantarum thallus breaking solution (LPBS). After 24h of alcohol injury, lactobacillus plantarum concentrations of 0, 1.0×105, 1.0×106, 1.0×107 and 1.5×107 cfu/mL were added to protect zebrafish larvae. Then with the treatment of lactobacillus plantarum after 48h, activities of alanine transaminase (ALT), aspartate transaminase (AST), superoxide dismutase (SOD) and malondialdehyde (MDA) in zebrafish tissue homogenate were respectively determined. Keap-Nrf2-ARE signal pathway related gene expression conditions were also analyzed, including nuclear factor (erythroid-derived 2)-like 2(Nrf2), Kelch like ECH associated protein 1(Keap1), catalase(CAT), hemooxygenase1(HO1) and Glutathione S-Transferase Kappa 1(gstk1). Results showed that: in comparison with the control group, the LPBS with dosage of 1.0×107 cfu/mL remarkably improved the activities of SOD, CAT, HO1and gstk1 in zebrafish larvae liver (P<0.05), resulting in significant increase of the protein expression level of Nrf2 (225.78%) and suppression of Keap1 gene expression (73.67%)(P<0.01). As confirmed by the results, lactobacillus plantarum activated the Keap-Nrf2-ARE signal pathway from the level of transcription, the up-regulation of the expression quantity of Nrf2 protected the organism from oxidative stress and maximally reduced liver injury.