Expression of α-smooth muscle actin and collagen I in lung fibroblasts of hyperoxia-exposed newborn rats / 中国小儿急救医学

ABSTRACT

ObjectiveTo study the expression and the role of α-smooth muscle aetin (α-SMA) and collagen Ⅰ ( Col Ⅰ ) in lung fibroblasts of newborn rats with hyperoxia-induced lung injuries.Methods Thirty full-term newborn Wistar rats were randomly assigned to hyperoxia group (90％ oxygen exposure,n =15 ) and air group (room air exposure,n =15) within 12 h after birth.Then lung fibroblasts were isolated and primary cultured from rat lungs on postnatal 3 d,7 d,and 14 d.The distribution of α-SMA protein were measured by immunohistochemistry.The levels of Col Ⅰ were detected by ELISA.ResultsThere were no significant differences in the levels of α-SMA and Col Ⅰ expressions between the two groups at 3 d ( P＞0.05 ).While the expression of α-SMA ( 112.60 ± 4.61 vs 94.69 ± 2.38,200.30 ± 3.97 vs 103.04 ± 1.91,P＜0.01 ) and Col Ⅰ protein [ ( 28.66 ± 1.15 ) μ.g/L vs ( 24.62 ± 3.15 ) μg/L,( 30.60 ± 0.65 ) μg/L vs (27.46 ± 1.68 ) μg/L,P ＜ 0.05 ] in lung fibroblasts caused by hyperoxia were significantly higher than those in air-exposed group on postnatal 7 d and 14 d.There was positive correlation between α-SMA and Col Ⅰ protein ( r =0.72,P＜0.01 ).ConclusionHyperoxia promotes differentiation of lung fibroblasts into myofibroblasts,and synthesis of type Ⅰ collegen in neonatal rats,which leads to lung fibrosis finally.