Effects of insulin-like growth factor I on the expression of collagen I in full-term rats with hyperoxia-induced chronic lung diseases

Objective:To investigate the expression and effect of collagen I in full-term rats with hyperoxia-induced chronic lung diseases and the effects of insulin-like growth factor I on the expression of collagen I.Methods:One hundred and forty-four full-term rats are randomly exposed to hyperoxia(hyperoxia group)and to room air(room air group).CLD is induced by hyperoxia exposure.We use immunohistochemical method to detect the expressions of collagen I and IGF-I at 1,3,7,10,14 and 21 days after exposure.Results:The expressions of collagen I and IGF-I decrease significantly in hyperoxia group compared with room air group at 3d to 10d after hyperoxia exposure(P0.05),otherwise increase significantly in hyperoxia group compared with room air group at 14d to 21d after hyperoxia exposure(P0.05).The expression of IGF-I correlates positively with that of collagen I.Conclusion:collagen I is involved in inhibition of alveolarization and lung fibrosis in the development of CLD,IGF-I is one of the most important growth factors to influence the synthesis of collagen I.