Table 1.
Extensor digitorum longus muscle protein contents and contractility 3 and 14–18 days after either one or five bouts of eccentric contractions were performed in vivo by mdx mice
| 1 Bout +3 |
5 Bouts +3 |
5 Bouts +Full |
||||
|---|---|---|---|---|---|---|
| Control | Injured | Control | Injured | Control | Injured | |
| Weight, mg | 21.0 ± 1.9 | 19.8 ± 1.4 | 17.5 ± 0.9 | 19.2 ± 1.0 | 22.5 ± 1.1 | 21.7 ± 0.8 |
| Total protein, mg | 3.9 ± 0.2 | 3.3 ± 0.2* | 3.1 ± 0.2 | 3.5 ± 0.2 | 3.9 ± 0.1 | 4.1 ± 0.3 |
| Total contractile protein, mg | 1.7 ± 0.2 | 1.2 ± 0.1* | 1.3 ± 0.1 | 1.3 ± 0.1 | 1.8 ± 0.1 | 1.8 ± 0.1 |
| Peak twitch force, mN | 65.1 ± 7.0 | 52.2 ± 3.1* | 50.0 ± 9.4 | 55.8 ± 7.9 | 69.9 ± 7.3 | 77.7 ± 4.4 |
| Peak isometric tetanic force, mN | 417 ± 39 | 290 ± 13* | 370 ± 21 | 372 ± 32 | 425 ± 27 | 469 ± 12 |
| Maximal rate of force development, N/s | 10.7 ± 0.9 | 7.3 ± 0.4* | 7.2 ± 0.9 | 8.4 ± 0.7 | 10.1 ± 0.9 | 11.4 ± 0.4 |
| Maximal rate of relaxation, N/s | −24.2 ± 2.4 | −13.6 ± 0.6* | −15.9 ± 2.3 | −17.1 ± 1.6 | −21.6 ± 1.6 | −25.8 ± 0.8* |
Values are means ± SE. Full, 14 or 18 days after the final bout of eccentric contractions.
*
Significantly different than controls (within group; P < 0.05). The age at euthanization was 124 days for 1 bout +3, 116 days for 5 bouts +3, 140 days for 5 bouts+Full (14-day interval), and 160 days for 5 bouts +Full (18-day interval).