Tetrazole exerts anti-hepatitis effect in mice via activation of PI3K/Akt pathway, inhibition of cell autophagy and suppression of inflammatory cytokine expressions

Abstract

Purpose: To investigate the effect of tetrazole on concanavalin A (Con A)-induced hepatitis in mice, and the underlying mechanism(s). Methods: Thirty 5-week-old, male BALB/c mice (mean weight, 30.5 ± 1.04 g) were used for this study. They were randomly assigned to six groups of five mice each: control group, hepatitis group and four treatment groups. With the exception of control group, hepatitis was induced in all mice with Con A (20 mg/kg) via their tail veins. The treatment groups received varied doses of tetrazole (1.0 - 6.0 mg/kg) within 1 h after hepatitis induction, while mice in the control group received an equivalent volume of normal saline in place of tetrazole. Serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined while expressions of interleukin-2 (IL-2), tumor necrosis factor ߙ) TNF-ߙ ,(and interferon gamma (IFN-ߛ (were evaluated by enzyme-linked immunosorbent assay (ELISA) kits. Expressions of protein kinase B (Akt), phosphoinositide 3-kinase (PI3K), nuclear transcription factor- ߢB (NF-ߢB), and autophagy-related genes were determined by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting. Results: Con A-induced hepatitis significantly increased the activities of serum ALT and AST in the mice. However, after treatment with tetrazole, the activities of these enzymes were significantly and dose-dependently reduced in the treatment groups, relative to hepatitis group (p < 0.05). The levels of IL-2, IFN-ߛ and TNF-ߙ were significantly increased in hepatitis group when compared with the control group (p < 0.05). However, treatment with tetrazole significantly inhibited the expressions of these parameters. There were no significant differences in the levels of expressions of Akt mRNAs among the treatment groups (p > 0.05). The levels of expressions of LC3II and Beclin 1 were also significantly upregulated in hepatitis group, when compared with control group (p < 0.05). However, expression levels of LC3II and Beclin 1 were significantly and dose-dependently reduced by tetrazole treatment Conclusion: Tetrazole is effective in the treatment of hepatitis via mechanisms involving the activation of PI3K/Akt pathway, inhibition of cell autophagy and suppression of inflammatory cytokines expressions.