Abstract
AIM: Skeletal muscle satellite cells (SCs) are important for muscle repair and hypertrophy in response mechanical stimuli. Neuron-glial antigen 2 positive (NG2(+)) and alkaline phosphatase positive (ALP(+)) pericytes may provide an alternative source of myogenic progenitors and/or secrete paracrine factors to induce Pax7(+) SC proliferation and differentiation. The purpose of this study was to investigate NG2(+) and ALP(+) cell quantity, as well as SC content and activation in human skeletal muscle following prolonged concentric (Conc) or eccentric (Ecc) resistance training.
METHODS: Male subjects engaged in unilateral resistance training utilizing isolated Ecc or Conc contractions. After 12 weeks, muscle biopsies were analyzed for NG2(+) and ALP(+) pericytes, total Pax7(+) SCs, activated SCs (Pax7(+)MyoD(+)), and differentiating myogenic cells (Pax7(-) MyoD(+)).
RESULTS: NG2(+) cells localized to CD31(+) vessels and the majority co-expressed ALP. NG2(+) pericyte quantity decreased following both Conc and Ecc training (p<0.05). ALP(+) pericyte quantity declined following Conc (p<0.05), but not Ecc training. Conversely, total Pax7(+) SC content was elevated following Conc only (p<0.001), while Pax7(+)MyoD(+) SC content was increased following Conc and Ecc (p<0.001). Follow up analyses demonstrated that CD90(+) and PDGFRα(+) mononuclear cell proliferation was also increased in response to both Conc and Ecc training (p<0.01).
CONCLUSION: Resistance training results in a decline in pericyte quantity and increase in mesenchymal progenitor cell proliferation, and these events likely influence SC pool expansion and increased activation observed post-training.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Journal of Applied Physiology |
| Vol/bind | 119 |
| Nummer | 10 |
| Sider (fra-til) | 1053-1063 |
| Antal sider | 11 |
| ISSN | 8750-7587 |
| DOI | |
| Status | Udgivet - 15 nov. 2015 |