Effects of steroids on the lung accumulation of neutrophil and monocyte in rabbits with endotoxemia.

Abstract

STUDY OBJECTIVE: To determine the effects of steroids on the lung accumulation of polymorphonuclear leukocytes (PMNs) and monocytes in rabbits with endotoxemia. DESIGN: A prospective, randomized, controlled animal trial. SETTING: Surgical research laboratory, Keio University School of Medicine. SUBJECTS: Twenty-four female Japanese white rabbits. INTERVENTIONS: Rabbits with endotoxemia were pretreated with steroids sufficient to inhibit the production of tumor necrosis factor (TNF) and to prevent the fall of BP. MEASUREMENTS AND RESULTS: The circulating leukocyte counts and the leukocyte accumulation in the lung were evaluated. Endotoxin caused a rapid decrease in circulating PMNs and monocytes followed by an 8-fold greater accumulation of PMNs (p < 0.001) and a 6.5-fold greater accumulation of monocytes (p < 0.05). Steroids failed to inhibit this initial drop of PMNs and monocytes. However, steroids inhibited the PMN accumulation in the lung by 50% (p < 0.05), without inhibiting the monocyte accumulation in the lung. CONCLUSIONS: These findings suggest that the lung accumulation of PMNs is dependent on TNF or other inflammatory mediators that are inhibited by steroids while the lung accumulation of monocyte is not.