Table 1.
Animal and cell characteristics
| 4-week FF | 4-week KO | 7-week FF | 7-week KO | |
|---|---|---|---|---|
| Age (weeks) | 14.0 ± 0.1 | 13.9 ± 0.2 | 17.1 ± 0.1 | 16.8 ± 0.2 |
| Heart rate (min−1) | 487 ± 18 | 433 ± 24* | 498 ± 19 | 395 ± 11* |
| BW (g) | 23.7 ± 0.6 | 26.4 ± 0.7* | 27.0 ± 0.7 | 24.6 ± 0.7* |
| LVW (mg) | 75.7 ± 2.4 | 87.5 ± 2.7* | 89.0 ± 3.0 | 83.5 ± 3.0 |
| LW (mg) | 134 ± 2 | 182 ± 6* | 153 ± 5 | 232 ± 9* |
| LVW/BW | 3.2 ± 0.1 | 3.3 ± 0.0 | 3.3 ± 0.0 | 3.4 ± 0.1 |
| LW/BW | 5.4 ± 0.3 | 7.0 ± 0.2* | 5.7 ± 0.2 | 9.5 ± 0.4* |
| Cell length (μm) | 129.6 ± 1.8 | 127.6 ± 1.8 | 127.6 ± 1.7 | 131.9 ± 1.9 |
| Cell width (μm) | 22.0 ± 0.4 | 21.8 ± 0.4 | 22.2 ± 0.4 | 21.5 ± 0.3 |
| Fract. short. at 6 Hz (%) | 3.76 ± 0.54 | 2.92 ± 0.43 | 2.98 ± 0.32 | 1.43 ± 0.11* |
| dl/dtmin at 6 Hz (μm ms−1) | 0.101 ± 0.020 | 0.048 ± 0.007* | 0.075 ± 0.010 | 0.019 ± 0.004* |
BW, body weight; LVW, left ventricular weight; LW, lung weight; Fract. short., fractional shortening, *P < 0.05 vs. FF; nanimals: 4-week FF = 29, 4-week KO = 32; 7-week FF = 35; 7-week KO = 25; ncells (length/width): 4-week FF = 115, 4-week KO = 121; 7-week FF = 139; 7-week KO = 143; ncells (6 Hz function): 4-week FF = 13, 4-week KO = 13, 7-week FF = 15, 7-week KO = 11.