Abstract: Abstract：Objective To explore the effects of different degrees of intermittent hypoxia (IH) on the activation and the secretion of extracellular matrix in MLg lung fibroblast cell line. Methods MLg lung fibroblast cells in logarithmic growth phase were exposed for 5% O2 for 100 seconds and 21% O2 for 120 seconds in 1 h, 4 h and 8 h groups (IH1, IH4 and IH8) and normoxia group (21% O2 for 8 h, N group). The cells in each group were collected at the end of experiment. Real-time PCR was used to measure the mRNA expression levels of α-SMA and type Ⅰ collagen (COL1) A1, and Western blot assay was used to detect the protein expression levels of α-SMA and COL1. Results The mRNA and protein expression levels of α- SMA and COL1 were significantly increased in IH1, IH4 and IH8 groups than those in N group (all P < 0.05). Furthermore, expression levels of α- SMA and COL1 showed a time- dependent increase with IH exposure time. Conclusion The intermittent hypoxia can promote the cell activation and the extracellular matrix secretion of mouse lung fibroblast cells, which may be related with the oxidative stress.

Key words: Key words: lung fibrosis, intermittent hypoxia, extracellular matrix, α-SMA, type I collagen