Intra-amniotic endotoxin and postborn hyperoxic exposure upregulate transforming growth factor-?1 and ?-smooth muscle actin in newborn mice lung / 第三军医大学学报

ABSTRACT

Objective To investigate the expressions of transforming growth factor-?1(TGF-?1)and ?-smooth muscle actin(?-SMA)in the lungs of mice with intra-amniotic endotoxin priming and exposed to 60% hyperoxia after born in order to elucidate the possible relationship with bronchopulmonary dysplasia(BPD).MethodsFifty C57 pregnant mice were divided into 2 groupslipopolysaccharide(LPS,40 ?g/L)group and saline solution group,and then received an intra-amniotic injection of corresponding solution on E15.The neonatal mice of each group were randomized to be set in 60% oxygen exposure or in room air.So there were 4 subgroups,LPS+air,LPS+hyperoxia,saline+air and saline+hyperoxia groups.On days 1,3,7,10 and 14 after birth(8 rats each time point),the lung histological changes was assessed with hematoxylin and eosin(HE)staining for radial alveolar counting(RAC).The expressions of TGF-?1 and ?-SMA proteins were detected by immunohistochemical and immunofluorescence staining,and the expressions of TGF-?1 and ?-SMA mRNA by real-time polymerase chain reaction(RT-PCR).ResultsIn the LPS+hyperoxia group and saline+hyperoxia group,RAC began to decrease on day 3,and then further declined in a time-dependent manner.Compared with saline+hyperoxia group,LPS+hyperoxia group had significantly lower RAC(P