OBJECTIVETo investigate the role of p38 mitogen-activated protein kinase (MAPK) signal transduction pathway in the Kupffer cells production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in severely burns rats.

METHODSMale health adult Sprague-Dawley rats were randomized into four groups: sham burn rats given vehicle, sham burn rats given the p38 MAP kinase inhibitor SB203580, rats given a 30% total body surface area (TBSA) full-thickness burn and fluid resuscitation plus vehicle, and burn rats given injury and fluid resuscitation plus SB203580. Rats from each group were killed at 24 h after burn or sham burn and Kupffer cells (KCs) were isolated. After 18 h incubation, KCs next were stimulated with 50 ng/ml of LPS for 18 h. After stimulation, supernatants were removed for analysis of TNF-alpha and IL-1beta levels by ELISA. The TNF-alpha and IL-1beta mRNA expressions (by quantitative real-time RT-PCR) and the activities of p38 MAPK and JNK (by Western blot analysis) in KCs were examined.

RESULTSEighteen hours after 50 ng/ml LPS stimulation, KCs from burn rats released significantly higher levels of TNF-alpha and IL-1beta than did shams. The mRNA levels of TNF-alpha and IL-1beta in KCs increased significantly postburn. Western blot analysis suggested that expression of phosphorylated p38 MAPK and JNK were increased in KCs harvested from burn group after stimulation with LPS compared with those from sham group. In vivo administration of SB203580 markedly suppressed both the release of TNF-alpha and IL-1beta and the mRNA expressions of TNF-alpha and IL-1beta in KCs from both sham and burn rats. p38 MAPK activity in KCs was abolished by administration with SB203580, whereas JNK was not.

CONCLUSIONSp38 MAPK signal transduction pathway mediates KCs production of proinflammatory cytokines TNF-alpha and IL-1beta in severely burned rats.