Background: Increasing evidence suggests that a close interaction of Kupffer cells with T cells plays a central role in concanavalin A-induced hepatic injury in mice, but the underlying mechanisms remain obscure. The present study aimed to determine the relative roles of Th1 and Th17 type responses in concanavalin A-induced hepatic injury in mice, and to investigate whether or not Kupffer cells contribute to hepatic injury via a Th1 or Th17 type response-dependent pathway.
Methods: Immune-mediated hepatic injury was induced in C57BL/6 mice by intravenous injection of concanavalin A. Kupffer cells were inactivated by pretreatment with gadolinium chloride 24 hours before the concanavalin A injection. The interferon-gamma (IFN-gamma) and interleukin-17 (IL-17) pathways were blocked by specific neutralizing antibodies. Hepatic injury was assessed using serum transferase activity and pathological analysis. Expression of inflammatory cytokines within the liver was detected by real-time polymerase chain reaction and immunohistochemistry.
Results: Neutralization of IFN-gamma significantly attenuated concanavalin A-induced hepatic injury. However, neutralization of IL-17 failed to suppress the injury. Inactivation of Kupffer cells by gadolinium chloride pretreatment protected against concanavalin A-induced injury and significantly reduced hepatic cytokine levels including TNF-alpha, IL-6 and IFN-gamma but not IL-17.
Conclusion: Our findings suggest that Kupffer cells contribute to concanavalin A-induced hepatic injury via a Th1 type response-dependent pathway and production of inflammatory cytokines including TNF-alpha, IL-6 and IFN-gamma.