Involvement of IL-10, an anti-inflammatory cytokine in murine liver injury induced by Concanavalin A.

A mechanism of liver injury such as, viral hepatitis or autoimmune hepatitis is considered to involve the impairment of hepatocytes mainly mediated by T-cell immunity, but the roles of a variety of cytokines involved in regulation remain unclarified. We investigated the involvement of various cytokines, particularly, interleukin-10 (IL-10) which is considered to be an anti-inflammatory cytokine, in a murine model of experimental liver injury induced by Concanavalin A (Con A). The model of liver injury was made by intravenous injection of Con A (0.5 &mgr;g) through the caudal vein in 6-week-old female BALB/c mice weighting 20 g. By collecting blood before and at 1, 3, 6, 12 and 24 h after the injection of Con A, alanine aminotransferase (ALT) levels were sequentially measured, and liver tissue was sampled to examine liver injury. Furthermore, TNF-alpha, IL-4 and IL-10 levels were sequentially determined by enzyme-linked immunosorbent assay (ELISA). Serum ALT significantly increased between 3 and 24 h after the Con A injection, and spotty necrosis was histologically observed, suggesting mild liver injury. TNF-alpha and IL-4 increased soon after the injection of Con A. IL-10 increased bimodally soon after and at 12 h after the Con A injection. After neutralizing antibodies (1 &mgr;g) to IL-10 were intraperitoneally injected into the same model at 6 h before Con A treatment, serum ALT levels and the histology of the liver were examined 12 h after the Con A injection. ALT was significantly higher in the group treated with anti-IL-10 antibody (130.7+/-33.5 IU per I) than in the non-treated group (56.5+/-3.5 IU per I) (P<0.05). Histological examination showed spotty necrosis in the group treated with anti-IL-10 antibody. These results suggest that IL-10 has inhibitory effect on liver injury in a murine model of Con A-induced experimental liver injury mediated by cellular immunity.