The Effects Of Quercetin On Signal Transduction Pathway Of Glutathione Metabolism Of Hepatocytes

ObjectivesTo investigate the effects of quercetin on the contention of glutathione and its metabolic enzymes and their levels of mRNA in rat hepatocytes. To investigate the mechanism and targets of quercetin’s effects on between Keapl-Nrf2 -ARE access and GSH metabolism by applying three kinds of typical MAPKs kinase inhibitors (SP600125, SB203580, PD98059) in the study. Then to provide scientific basis for further research to kown the effects of quercetin on the capacity of antioxidant and the health of human.MethodsMTT method was used to measure the survival viability of rat hepatocytes after being treated by different concentrations of quercetin and MAPKs inhibitors (SP600125, SB203580, PD98059). The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in culture medium were measured by commercial kits respectively. The content of reduced glutathione (GSH) and oxidized glutathione (GSSG) in rat hepatocytes was detected by HPLC assay. The activities of glutathione peroxidase (GSH-Px), γ-glutamate cysteine Ligase (Y-GCL),glutathione S-transferase (GST) andglutathione reductase (GR) in rat hepatocytes were assayed by reagent kits respectively. The rat liver cells were randomized into control group,quercetin group(Q),SP600125 group (SP)、SB203580 group (SB)、 PD98059 group (PD)、 quercetin and SP600125 group(Q+SP)、 quercetin and SB203580 group (Q+SB)、 quercetin and PD98059 group (Q+PD) RT-PCR method was used to test the changes of mRNA levels of GSH-Px/GST/GR/ γ-GCL.Western blot method was used to test the level of P38 and p-P38.The level of JNK. p-JNK、 ERK and p-ERK were tested by the Luminex method.ELLESA Kit wasused to test Keap1.ResultsCompared with the control group, the activity of rat hepatocytes of 30、40 and50 μ mol/L group were decreased significantly. The content of GSH and the activity of GST and γ-GCL in rat hepatocytes of 20 μ mol/L group were increased, while the activity of GSH-Px in rat hepatocytes of 20 μ mol/L group were decreased in comparison to the control group. The concentration of SP600125 above 10 μ mol/L,SB203580 above 30 μ mol/L, PD98059 above 50 μ mol/L can decreased significantly of rat hepatocytes. Compared with the control group,the mRNA level of GSH-Px/GST/GR,p-JNK and Keapl of Q group increased significantly,but the levels of JNK,ERKandp-ERK decreased significantly.Compared with the control group,the mRNA level of γ-GCL and JNK of SP group decreased significantly,but the levels of p-JNK increased significantly.Compared with the SP group,the level of JNK decreased significantly,the mRNA level of γ-GCL, p-JNK and Keap1 of Q+SP group increased significantly.Compared with the control group,the levels of ERKandp-ERK decreased significantly and the mRNA level of GSH-Px/γ-GCL and Keapl of PD group increased significantly.Compared with the PD group,the mRNA level of GSH-Px/GST/GR/γ-GCL,ERK and p-ERK of Q+SP group decreased significantly, the level of Keap1 increased significantly.ConclusionsQuercetin could promote GSH production and the level of mRNA and activities of GST and γ-GCL in rat hepatocytes by the JNK MAPK.