OBJECTIVELung fibrosis is the ultimate outcome of hyperoxia-induced chronic lung diseases (CLD) and connective tissue growth factor (CTGF) is correlated with fibrosis. This study investigated the role of CTGF in hyperoxia-induced CLD.

METHODSFifty premature rats were randomly exposed to hyperoxia (Model group) and to room air (Control group) (n = 25 each). CLD was induced by hyperoxia exposure. The expression of CTGF was detected by immunohistochemical method at 1, 3, 7, 14 and 21 days after exposure. The severity of pulmonary fibrosis was evaluated.

RESULTSIn the Control group there was a slight expression of CTGF in the bronchial epithelial cells and vascular endothelial cells. The intensity and range of CTGF expression in the Model group were similar to the Control group on days 1, 3 and 7 of exposure. On the 14th day, CTGF was expressed in some alveolar epithelial cells, fibroblasts and interstitial cells, and the intensity of CTGF expression increased significantly compared with the Control group, with the IODT of CTGF of 10.53 +/- 4.24 vs 5.58 +/- 1.18 (P < 0.01). On day 21, the expression intensity and range of CTGF in the Model group (IODT: 16.61 +/- 5.39) increased compared with that of Control group (P < 0.01). The expression of CTGF was correlated with the degree of fibrosis in the Model group on days 14 and 21 (r = 0.903, r = 0.926 respectively, P < 0.01).

CONCLUSIONSThe CTGF expression increased with the time of hyperoxia exposure and the development of fibrosis. CTGF is closely related to the development of hyperoxia-induced pulmonary fibrosis.