Fig. 2
3 days’ exposure to hyperoxia induced CLD in newborn rats. At 4th day, the W/D and the TP, LDH, and total cell counts in BALF of the hyperoxia group were significantly higher than in the air group (P < 0.01) (a-d). An obvious decrease 4 days after cessation of hyperoxia exposure (on postnatal day 8) was shown (P < 0.01). It was not different from the same day’s air control group (a-d). At day 8, there was a decline in RAC in the hyperoxia group compared with the air group (P < 0.05). RAC was also lower than in the air group at day 15 and 22 (P < 0.01) (f). At day 15 and 22, there was an increase in the level of HYP and the mRNA of type I procollagen in the hyperoxia group relative to the air group (P < 0.01) (e and g). A noticeable decrease in Cdyn in the hyperoxia group was recorded on day 22 (h). H: hyperoxia group; C: control group; CLD: chronic lung disease; BALF: bronchoalveolar lavage fluid; TP: Total protein; LDH: Lactate dehydrogenase activation; W/D: wet-weight/dry-weight ratios; HYP: hydroxyproline; Cdyn: dynamic lung compliance; RAC: Radial alveolar count; PC I: type I procollagen. *P <0.05, **P <0.01 vs. air group, n = 6 per group