Table 1.
Comparison of BWs, lung volumes, and volume-to-BW ratios, mean ± SE
| Age | BW, g
|
Lung volumes, ml
|
LV∶BW, ml/g × 10−2
|
|||
|---|---|---|---|---|---|---|
| SP-D(−/−) | SP-D(+/+) | SP-D(−/−) | SP-D(+/+) | SP-D(−/−) | SP-D(+/+) | |
| 2 days | 1.8 ± 0.1* | 3.4 ± 0.1 | ND | ND | ND | ND |
| 5 days | 3.7 ± 0.3 | 4.6 ± 0.2 | ND | ND | ND | ND |
| 7 days | 3.9 ± 0.2* | 5.3 ± 0.2 | ND | ND | ND | ND |
| 14 days | 6.6 ± 0.2* | 7.7 ± 0.2 | ND | ND | ND | ND |
| 17 days | 10.9 ± 0.5 | 10.6 ± 0.7 | 0.36 ± 0.02 | 0.36 ± 0.03 | 3.25 ± 0.05 | 3.36 ± 0.03 |
| 3 wk | 10.9 ± 0.5* | 14.1 ± 1.2 | 0.36 ± 0.01 | 0.37 ± 0.03 | 3.43 ± 0.21† | 2.50 ± 0.18 |
| 6 wk | 23.2 ± 0.6 | 24.7 ± 0.5 | 0.63 ± 0.03 | 0.58 ± 0.02 | 2.71 ± 0.13† | 2.25 ± 0.01 |
| 9 wk | 25.2 ± 1.2 | 27.8 ± 1.3 | 0.55 ± 0.03 | 0.61 ± 0.02 | 2.10 ± 0.16 | 2.20 ± 0.09 |
| 28 wk | 36.9 ± 4.3 | 31.2 ± 1.6 | 0.67 ± 0.09 | 0.58 ± 0.06 | 2.03 ± 0.51 | 1.86 ± 0.10 |
LV∶BW, lung volume-to-BW ratio; ND, not determined.
*Significant statistical differences were observed in BWs, at 2 days, P = 0.0001; 7 days, P = 0.0002; 2 wk, P = 0.007; and 3 wk, P = 0.04.
† Significant statistical differences in LV∶BW ratios were observed at 3 wk (P = 0.02), due to differences in BW, and at 6 wk (P = 0.03), although BWs and lung volumes were not statistically different at the latter time point. n = 3–7 animals per group.