| First Author | Kiriaev L | Year | 2021 |
| Journal | Front Physiol | Volume | 12 |
| Pages | 771499 | PubMed ID | 34950049 |
| Mgi Jnum | J:324371 | Mgi Id | MGI:6841815 |
| Doi | 10.3389/fphys.2021.771499 | Citation | Kiriaev L, et al. (2021) Lifespan Analysis of Dystrophic mdx Fast-Twitch Muscle Morphology and Its Impact on Contractile Function. Front Physiol 12:771499 |
| abstractText | Duchenne muscular dystrophy is caused by the absence of the protein dystrophin from skeletal muscle and is characterized by progressive cycles of necrosis/regeneration. Using the dystrophin deficient mdx mouse model, we studied the morphological and contractile chronology of dystrophic skeletal muscle pathology in fast-twitch Extensor Digitorum Longus muscles from animals 4-22 months of age containing 100% regenerated muscle fibers. Catastrophically, the older age groups lost approximately 80% of their maximum force after one eccentric contraction (EC) of 20% strain with the greatest loss of approximately 92% recorded in senescent 22-month-old mdx mice. In old age groups, there was minimal force recovery approximately 24% after 120 min, correlated with a dramatic increase in the number and complexity of branched fibers. This data supports our two-phase model where a "tipping point" is reached when branched fibers rupture irrevocably on EC. These findings have important implications for pre-clinical drug studies and genetic rescue strategies. |
