Expression of mRNA species affecting growth and membrane homeostasis in skeletal muscle following eccentric exercise

Eccentric exercise leads to muscle damage with our recent work suggesting an early response of components of membrane repair and remodeling at the transcriptome level. Estradiol has been reported to have membrane stabilizing properties but it is unclear if these are mediated at the transcriptome or post‐translational level. We measured skeletal muscle expression of mRNA for enzymes involved in membrane homeostasis (FOXO1, Caveolin 1 and SREBP‐2) and growth (DSCR1, DMPK and CapZα1) in healthy males following 8 days of either placebo (n=9) or 17‐beta‐estradiol (n=9) supplementation. Muscle biopsies were collected pre and post supplementation as well as 3 and 48 hours following an exercise protocol of 150 eccentric contractions. Quantification of mRNA expression was determined by RT‐PCR. FOXO1, Caveolin 1, SREBP‐2 and DSCR1 were elevated at 3h post exercise by 2.7, 1.4, 1.6 and 16.6 fold respectively, with no effect of supplementation. DMPK and CapZα1 were elevated at 48h post exercise by 2.6 and 1.8 fold respectively, with no effect of supplementation. These findings indicate an early and later temporal pattern in steady‐state mRNA content for genes involved in membrane synthesis (3h) and growth (3 and 48h) following eccentric exercise that is not influenced by17beta‐estradiol. (This research was funded by NSERC)