Figure 3

Lung clearance of inhaled Tc-DTPA. The kep of the 40% oxygen 2 week-exposure group was increased than that of the 21% oxygen 2 week-exposure group. The kep of the 40% oxygen 2, 4, 8 and 16 week-exposure groups and the 21% oxygen 8 week-exposure group were significantly increased as compared to that of the pre-exposure group. This increase, however, did not differ between the 40% and the 21% oxygen groups. The kep of the 90% oxygen 24 hour-exposure group was higher than that of the pre-exposure group, and that of the 48 hour-exposure group was higher than that of the 24 hour-exposure group. Values are expressed as means ± SD; * p < 0.05 and ** p < 0.01 as compared to the value of the 21% oxygen exposure duration-matched control or pre and the 90% oxygen 24 hour-exposure group. ⁺ p < 0.05 and ⁺⁺ p < 0.01 as compared to the value of the pre-exposure group. n = 5 in the pre-exposure group; n = 5 in each 40% oxygen exposure group; n = 5 in each 21% oxygen exposure group; n = 5 (24 hours), 6 (48 hours) and 8 (72 hours) in the 90% oxygen exposure groups.