Retinoic Acid Protect Against Hyperoxia Induced Lung Injury Though Down-Regulat Ing Connective Tissue Growth Factor

Objective:To investigate the mechanism that retinoic acid(RA)protect against hyperoxia-induced lung injury.Methods:Ninety Sprague Dawley rats were randomly assigned into three groups with thirty rats in each group. group A:air contol;group B: hyperoxia group;group C:hyperoxia+RA group. Lungs were removed by tnoracotomy on postnatal 4,7,14 day. Radical alveolar counts (RAC) were observed by HE under light microscope. The mRNA lever of CTGF in lungs were analyzed by reverse transcriptase polymerase chain reaction(RT-PCR). The expression of CTGF protein in lungs were detected by immunohistochemistry stain .Results:With hyperoxia exposure prolonged,the lungs developed inflammatory cell infiltration,alveolar structure disorder,alveolar number decreased,alveolar interstitial thicken in group B and C. Pathological changes of group C was weaker than that of group B.The CTGF mRNA and protein expression were up-regulated in the group B and C at day 7 and 14 compared with group A(P<0.05);and significant diference was found that CTGF mRNA and protein expression in group C was lower than group B at day 14.Conclusion:The expression of CTGF mRNA and protein were up-regulated by hyperoxia-induced lung injury.Retionic acid could protect against hyperoxia lung injury though down regulating CTGF.