Effect of hyperoxia on the expression of surfactant protein C in premature rats

Objectives To explore the effect of hyperoxia on expression of surfactant protein C(SP-C)in premature rats.Methods Sprague-Dawley(SD)newborns of 21-day gestational age were randomly assigned to air group and hyperoxia group within 12 h ～ 24 h after birth.After 1 to 14 days exposure,SP-C mRNA in lung tissues of these rats were detected by RT-PCR.Immunohistochemistry and Western-blot were used to detect SP-C protein.Results The SP-C expression in premature rats of air group was highest on day 1 and began to decrease after day 4.The positive staining was restricted to the typeⅡalveolar epithelial cells.Compared with air group,the SP-C mRNA and protein were significantly lower on day 1 in hyperoxia group but gradually increased and achieved a peak on day 7,then decreased again.Conclusions Hyperoxia exposure lead to a down regulation or functional impairment of the SP-C expression,this may be an important factor which influences the development of hyperoxia lung injury.