Expression of myofibroblast markers are increased in hypoxic pulmonary fibroblasts. A. Normoxic or hypoxic (1% oxygen, 8 days) pulmonary fibroblasts were analysed for mRNA expression of alpha smooth muscle actin (α-SMA), collagen I and collagen III using quantitative real-time PCR. Hypoxic cells expressed increased levels of α-SMA (p < 0.05), colIagen I (p < 0.001) and collagen III (p < 0.05) compared to normoxic controls. B. α-SMA protein expression was increased in hypoxic cells. This is a sample blot from n = 3 experiments. The increase in α-SMA was statistically significant when densitometry was performed. Results are mean +/- SD for n = 3 experiments. Students t test was used for statistical analysis. C. Immunocytochemistry for α-SMA (red) demonstrated that increased levels of the protein was present in hypoxic cells where it formed microfilaments. Cells were counterstained with nuclear specific DAPI (blue).