The expression of surfactant protein genes hyperoxia-induced neonatal rat lung injury

Objective:To observe the effects of hyperoxiaon the changes of pulmonary histology and surfactant protein gene expression.Methods:SD newborns which less than 6 h old were randomly divided into 2 groups:normal air control group and hyperoxia group.The lungs of rats were removed at the time points 1,4,7,14 d,histopathological changes of the lung tissues were examined by HE staining and the lung factor were calculated(lung weight/body weight ×100%);the expression of all surfactant protein genes were detected by semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR).Results:To compare with corresponding air control group,in hyperoxia group,the body weight is significantly deceased after 14 days of hyperoxia exposure(P0.01),and the lung factor increased significantly from day 7(P0.05),and kept increasing at 14 d(P0.05);the levels of SP-A and SP-D mRNAs increased significantlyfromday1(P0.05),remained higher at 4 d and 7 d(P0.05),and began tosignificantlydecreased at 14 d(P0.05);the levels of SP-B and SP-C mRNAs increased from day 1(P0.05),remained higher at 4 d(P0.05),but there were no significant differences at 7 d(P0.05),and began to significantly decreased at 14 d(P0.05).Conclusion:Prolonged hyperoxia can inhibit the development of alveolar and the expression of surfactant protein genes indicating that alterations in gene expression,contribute to tissue injury.