Table 3.
LV 2D‐Transthoracic echocardiography and fibrosis measurements
| 9 weeks old | 24 weeks old | |||||
|---|---|---|---|---|---|---|
| Sedentary | Juvenile exercise | Sedentary | Juvenile exercise | Adolescent exercise | Adult exercise | |
| LV/body weight ratio (mg g−1) | 2.94 ± 0.46 | 3.87 ± 0.34* | 2.14 ± 0.18 | 2.36 ± 0.16* | 2.43 ± 0.14* | 2.32 ± 0.19* |
| LVIDd (mm) | 6.62 ± 0.62 | 7.01 ± 0.36* | 7.03 ± 0.26 | 7.21 ± 0.28 | 7.28 ± 0.24 | 7.09 ± 0.51 |
| LVIDs (mm) | 3.27 ± 0.45 | 3.61 ± 0.33* | 3.43 ± 0.35 | 3.86 ± 0.20* | 3.74 ± 0.32 | 3.58 ± 0.26 |
| LVAd (mm) | 3.79 ± 0.74 | 3.96 ± 0.43 | 4.52 ± 0.61 | 4.84 ± 0.77 | 4.73 ± 0.70 | 4.62 ± 0.69 |
| LVAs (mm) | 0.87 ± 0.29 | 0.90 ± 0.16 | 1.22 ± 0.30 | 1.27 ± 0.28 | 1.36 ± 0.46 | 1.29 ± 0.21 |
| FAC (%) | 77 ± 4 | 77 ± 3 | 73 ± 4 | 75 ± 3 | 75 ± 5 | 72 ± 3 |
| FS (%) | 51 ± 6 | 48 ± 4 | 52 ± 3 | 46 ± 2* | 48 ± 4 | 50 ± 3 |
| EF (%) | 86 ± 4 | 83 ± 3 | 87 ± 3 | 83 ± 2 | 84 ± 4 | 85 ± 2 |
| Interstitial/reparative fibrosis (% collagen) | NA | NA | 1.84 ± 0.61 | 1.56 ± 0.23 | 1.49 ± 0.52 | 1.85 ± 0.59 |
| Perivascular fibrosis ratio of Adventitia:lumen | NA | NA | 0.27 ± 0.12 | 0.37 ± 0.13 | 0.34 ± 0.09 | 0.29 ± 0.10 |
LV, left ventricle; LVIDd and LVIDs, LV internal diameter at diastole and systole; LVAd and LVAs, mid‐papillary LV area at diastole and systole; FAC, fractional area change; FS, fractional shortening; EF, ejection fraction; NA, not assessed. Data presented as means ± SD. For echocardiography: 9‐week‐old rats, sedentary n = 15, juvenile n = 15; 24‐week‐old rats, sedentary n = 9, juvenile n = 11, adolescent n = 14, adult n = 13. For fibrosis, n = 8 per group. 9‐week‐old rats were compared using a Student's unpaired t test. 24‐week‐old rats were compared using one‐way ANOVA with Newman‐Keuls post hoc analysis. * P < 0.05 vs. sedentary.