IL-33 ameliorates liver injury and inflammation in Poly I:C and Concanavalin-A induced acute hepatitis

The IL-33/ST2 axis is known to be involved in liver pathologies and IL-33 is over-expressed in mouse hepatitis models. We aimed to investigate the proposed protective effect of IL-33 in murine fulminant hepatitis induced by a Toll like receptor 3 (TLR3) viral mimetic, Poly I:C or by Concanavalin-A (ConA). The Balb/C mice were administered intravenously with ConA (15 mg/kg) or Poly I:C (30 μg/mouse) to induce acute hepatitis along with vehicle control. The recombinant mouse IL-33 (rIL-33) was injected (0.2 μg/mouse) to mice 2 h prior to ConA or Poly I:C injection to check its hepato-protective effects. The gross lesions, level of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), histopathology (H&E staining) and levels of IFNγ and TNFα were measured by ELISA. The gross pathological liver injury induced by Poly I:C or ConA was reduced by rIL-33 administration in mice. The levels of AST and ALT were significantly (P ≤ 0.05) higher in mice challenged with Poly I:C or ConA in comparison to control mice. The rIL-33 pre-treated mice in both Poly I:C and ConA challenge groups showed significantly (P ≤ 0.05) lower levels of AST and ALT, and decreased liver injury (parenchymal and per-vascular necrotic areas) in histological liver sections. The soluble levels of TNFα and IFNγ were significantly (P ≤ 0.05) raised in Poly I:C or ConA challenged mice than control mice. The levels of TNFα and IFNγ were significantly reduced (P ≤ 0.05) in rIL-33 pre-treated mice. In conclusion, the exogenous IL-33 administration mitigated liver injury and inflammation (decreased levels of IFNγ and TNFα) in Poly I:C and ConA-induced acute hepatitis in mice.