Fig. 4.

CD31 and α-smooth muscle actin (SMA) expression in male and female human pulmonary microvascular endothelial cells (HPMECs) upon exposure to hyperoxia. CD31 and α-SMA protein expression in male and female HPMECs exposed to room air (RA) (RA-5% CO₂) and 72 h of hyperoxia (HO) (95% O₂-5% CO₂) are shown. Representative Western blot images and densitometry analyses are shown. Values are means ± SE of 3 independent biological replicates (n = 3/group). Significant differences between baseline and subsequent time points within the same sex are indicated by **P < 0.01 or ***P < 0.001; significant differences between male and female HPMECs at each time point are indicated by ##P < 0.01 or ###P < 0.001.