Oestrogen-dependent satellite cell activation and proliferation following a running exercise occurs via the PI3K signalling pathway and not IGF-1
| Autor: | Gary Mangan, Joe Quadrilatero, Andrew S. Mitchell, Eric Bombardier, Peter M. Tiidus |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
medicine.medical_specialty
Satellite Cells Skeletal Muscle Physiology Ovariectomy Population Radioimmunoassay Fluorescent Antibody Technique Biology Rats Sprague-Dawley Wortmannin Phosphatidylinositol 3-Kinases chemistry.chemical_compound Physical Conditioning Animal Internal medicine medicine Animals Phosphatidylinositol Insulin-Like Growth Factor I education PI3K/AKT/mTOR pathway Cell Proliferation Soleus muscle education.field_of_study Estradiol Estrogens Hedgehog signaling pathway Rats Endocrinology chemistry Ovariectomized rat Female Cell activation Signal Transduction |
| Zdroj: | Acta Physiologica. 212:75-85 |
| ISSN: | 1748-1708 |
| Popis: | Aim: The purpose of this study was to determine whether 17b-estradiol (E2) enhances the activation, proliferation and differentiation of muscle satellite cells (SC) following eccentric exercise either via insulin-like growth factor-1 (IGF-1) or through phosphatidylinositol 3-kinase (PI3K) signalling. Methods: This study used 64, 9-week-old, ovariectomized Sprague–Dawley rats that were divided into eight treatments groups based on oestrogen status (0.25 mg oestrogen pellet or sham), exercise status (90 min run @ 17 m min � 1 , � 13.5° or unexercised) and PI3K signalling inhibition (0.7 mg wortmannin kg � 1 body weight or DMSO control). Results: Significant increases in total SCs were found in both soleus and white gastrocnemius muscles (immunofluorescent co-localization of Pax7 + nuclei) 72 h following eccentric exercise (P < 0.05). Oestrogen supplementation caused a further enhancement in total SCs in exercised rats (P < 0.05). In animals where the PI3K pathway was inhibited, regardless of oestrogen or exercise status, there was no significant enhancement of SC number in both the soleus or white gastrocnemius muscles. Interestingly, oestrogen supplementation lowered muscle levels of IGF-1 with this effect being most prominent in the soleus muscle. While IGF-1 was increased following exercise (P < 0.05), oestrogen supplementation abrogated this increase back to sedentary levels. Conclusion: These data suggest that the increase in SC population following exercise in oestrogen-supplemented females may be mediated via PI3K pathway signalling and not IGF-1. |
| Databáze: | OpenAIRE |
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