The effect of gingkgo injection on the expression of heme oxygenase-1 in the lungs of hyperoxia-induced preterm rats

Objective To study the expression of heme oxygenase-1(HO-1) in the lungs of hyperoxia-induced preterm rats and the effects of gingkgo injection on the expression of HO-1 mRNA and HO-1 to provide evidence for clinical usage of gingkgo injection in prevention and treatment of hyperoxia-induced lung injury in preterm infants.Methods Three days old,Sprague-Dawley preterm rats were randomly assigned to hyperoxia group(90% oxygen),room air group and hyperoxia+gingkgo injection group.The rats were sacrificed after 3 days and 7 days of exposure,the expression of HO-1 mRNA and HO-1 in the lungs were measured by reverse transcription polymerase chain reaction(RT-PCR) and by immunohistochemical techniques respectively.Results On day 3,the expression of HO-1 mRNA(0.17±0.08) and HO-1(7.23±0.63) turned weakly positive of rats in room air group;the expression of HO-1 mRNA of rats in hyperoxia group was significantly higher than that of room air group(0.72±0.33,P0.01),the expression of HO-1 was shown only on macrophages and it was significantly increased compared with rats in room air group(18.54±6.55,P0.05);the expression of HO-1 mRNA of rats in hyperoxia+gingkgo injection group was significantly reduced compared with those in hyperoxia group(0.43±0.18,P0.01),yet higher than that of room air group(P0.01);the expression of HO-1 in hyperoxia+gingkgo injection group was not significantly reduced in hyperoxia+gingkgo injection group(14.85±8.14,P0.05).On day 7,the expression of HO-1 mRNA was negative of rats in each group;the expression of HO-1 extremely weak or negative of rats in room air group,but shown strongly positive on macrophages of rats in hyperoxia group and was significantly higher than that of room air group(51.24±18.32,P0.01);the expression of HO-1 was significantly reduced of rats in hyperoxia+gingkgo injection group compared with that of hyperoxia group(39.43±13.57,P0.01),yet higher than that of room air group(P0.01).Conclusion This study shows that HO-1 is possibly involved in hyperoxia-induced lung injury of premature rats,gingkgo injection could down-regulate the expression of HO-1 gene in the lungs of hyperoxia-induced preterm rats.