Figure 3

The permeability of pulmonary epithelia after different days of hyperoxia exposure. Newborn rats received an intravenous injection of FD4. Fifteen minutes later, bronchoalveolar lavage fluid (BALF) and serum were collected, and the BALF:serum FD4 ratio was determined. 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.