P38 mitogen-activated protein kinase inhibition attenuates burn-induced liver injury in rats

Abstract

This study was made to evaluate the effect of SB203580, a specific p38 MAP kinase inhibitor, on burn-induced hepatic injury as well as the activation of nuclear factor (NF)-κB in severely burned rats. Sprague–Dawley rats were divided into three groups: (1) sham group, rats underwent sham burn; (2) burn group, rats given third-degree burns over 30% total body surface area (TBSA) and treated with vehicle plus lactated Ringer solution for resuscitation 4 ml/(kg % TBSA); and (3) burn plus SB203580 group, rats given burn injury and fluid resuscitation plus SB203580 (10 mg/kg i.v., 15 min and 12 h after burn). Hepatocellular injury (measured by serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) and hepatocellular function (determined by the indocyanine green dye retention rate (ICG R15)) were assessed at 24 h post-burn. Liver histologic changes were also analyzed. Burn trauma resulted in increased serum aminotransferases concentrations, decreased ICG R15, elevated serum tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels and hepatic TNF-α and IL-1β mRNA expressions, and worsen histologic condition. The level of Nuclear Factor (κ) inhibitor (IκBα) in liver was decreased and DNA-binding activity of Nuclear Factor-κB (NF-κB) was increased after thermal injury. p38 MAP kinase was more significantly activated in liver harvested from burn rats than from shams. SB203580 inhibited the activation of p38 MAP kinase, reduced the levels of TNF-α and IL-1β, and prevented burn-mediated liver injury. Both the IκBα level and NF-κB activity in the liver following burns was not affected by administration with SB203580. These findings suggest that (1) p38 MAP kinase activation is one important aspect of the signaling event that may mediate the release of TNF-α and IL-1β and contributes to burn-induced liver injury and (2) p38 MAP kinase does not influence the activation of NF-κB directly in the liver of severely burned rats.