Effect of granulocyte macrophage colony-stimulating factor on hyperoxia-exposed newborn rats

Objective To investigate the effect of granulocyte macrophage colony-stimulating factor(GM-CSF) on the hyperoxia-exposed lung injury in neonatal rats.Methods Thirty-two rats were equally randomized into four groups of A(exposed with 95% oxygen plus GM-CSF 9 μg/kg intranasally injection),B(intranasally injected with GM-CSF 9 μg/kg),C(exposed with 95% oxygen plus normal saline intranasally injection) and D(normal saline intranasally injection).Seven days later,the wet/dry ratio(W/D) of lung tissues was calculated,and the number of leucocytes and the levels of monocyte chemoattractant protein-1(MCP-1) and interleukin-8(IL-8) in the bronchoalveolar lavage fluid(BALF) were detected.The expression of MCP-1 mRNA in the lung tissue and the pathological score of lung injury were measured by RT-PCR and HE staining,respectively.Results Compared with groups of C and D,the pathological scores of lung injury,the W/D,the numbers of leucocytes and neutrophils in the BALF,the levels of MCP-1 and IL-8 and the expression of MCP-1 mRNA were all obviously increased in groups of A and B(P0.05).Except MCP-1 level and its mRNA expression,the indexes above were significantly different between group A and group B(P0.05).ConclusionGM-CSF can protect the the lungs from hyperoxia-induced injury in neonatal rats,which may be related to the inhibition of inflammatory reaction.