Figure 2

Effect of hyperoxia exposure on pulmonary edema after different days of hyperoxia exposure. Effects of hyperoxia exposure on pulmonary edema were determined by the wet-to-dry (W/D) ratio of lung weight (A) and extravascular lung water content (B) following exposure of newborn rats to normoxia or hyperoxia for 1, 3, 5 and 7 days. Hyperoxia significantly increased the W/D ratio of lung weight and extravascular lung water content compared with normoxia on 5 and 7 days. Data are the mean ± SEM (n = 6 in each group); *P < 0.05, ** P < 0.01 versus normoxia group; ## P < 0.01 versus 3 days of hyperoxia exposure group; $$ P < 0.01 versus 5 days of hyperoxia exposure group.