The expression of macrophage inflammatory protein-2 and the role of macrophage in rat endotoxin-induced acute lung injury

AIM and METHOD: In order to identify the pathogenesis of acute lung injury (ALI), the expression of macrophage inflammatory protein-2(MIP-2), monocyte chemoattractant protein-1(MCP-1) was assessed in the rat lung tissue of endotoxin-induced ALI using dot and in situ hybridization technique. TNFα and IL-8 of supernatant from cultured LPS-treated pulmonary intravascular macrophage (PIM) were also measured. RESULTS:The expression of MIP-2, MCP-1 mRNA in ALI groups were markedly higher than control group ( P 0 01),and reaching their peaks at ALI 3 h and ALI 6 h group respectively. Level of MIP-2 mRNA positively related to the myeloperoxidase (MPO) activity in plasma and lung homogenate ( P 0 05). The positive signal of MIP-2 mRNA was localized in pulmonary macrophage (M ) and LPS-treated PIM. The release of TNF α in LPS-treated PIM occured earlier than that of IL-8; however, the level of IL-8 kept rising longer.CONCLUSION:Pulmonary M  may play an important role in ALI by means of releasing MIP-2, TNF α,IL-8, etc.