Effects of a dual inhibitor of tumor necrosis factor-alpha and interleukin-1 on lipopolysaccharide-induced lung injury in rats: involvement of the p38 mitogen-activated protein kinase pathway.

Sepsis is a major cause of adult respiratory distress syndrome. In this study, we evaluated the effect of FR167653, which is a potent suppressant of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 production, on lipopolysaccharide (LPS)-induced lung injury and lethality in rats, and we examined the involvement of p38 mitogen-activated protein (MAP) kinase in the action of FR167653. Prospective, randomized study. Animal research facility in a university. Male Sprague-Dawley rats weighing 200-270 g. All the animals were assigned to one of the following four groups: control group, FR-only group, LPS-only group, and LPS/FR group. Animals in the LPS-only and LPS/FR groups received 6 mg/kg of LPS intravenously. The animals in the FR-only and LPS/FR groups also received an infusion of FR167653 at 0.2 mg x kg(-1) x hr(-1), commencing 30 mins before the LPS (or vehicle) injection and continuing for 5.5 hrs. LPS significantly induced the accumulation of pulmonary neutrophils and lung edema, both of which were significantly attenuated by treatment with FR167653. FR167653 also significantly decreased the LPS-induced lethality. Histologically, tissue damage was milder in the LPS/FR group than in the LPS-only group. Serum concentrations of TNF-alpha and IL-1beta and plasma concentrations of thromboxane B2 were all suppressed in the LPS/FR group compared with the LPS-only group. Western blot analysis revealed that FR167653 inhibited the phosphorylation of p38 MAP kinase in lung tissues. FR167653 administration decreased serum TNF-alpha and IL-1beta concentrations, which was associated with decreased lung injury and lethality. The mechanism responsible for the decreased TNF-alpha and IL-1 may be related to the inhibitory effect of FR167653 on p38 MAP kinase activation.