BioProject

Global microarray (HG U133 Plus 2.0) was used for the first time to investigate the effects of resistance exercise on the transcriptome in slow-twitch myosin heavy chain (MHC) I and fast-twitch MHC IIa muscle fibers of young and old women. More...

Global microarray (HG U133 Plus 2.0) was used for the first time to investigate the effects of resistance exercise on the transcriptome in slow-twitch myosin heavy chain (MHC) I and fast-twitch MHC IIa muscle fibers of young and old women. Vastus lateralis muscle biopsies were obtained pre and 4hrs post resistance exercise in the beginning (untrained state) and at the end (trained state) of a 12 wk progressive resistance training program. Overall design: A total of 14 females were included in this investigation. The participants included 8 young (23±2y) and 6 old (85±1y) females. All subjects participated in 12 wks of progressive resistance training consisting of bilateral knee extensions with 3x10 reps at 70% of 1-RM, and 3d/wk for a total of 36 training sessions. Vastus lateralis biopsies were obtained in conjunction with the 1st and 36th (last) training session and included a basal biopsy and another biopsy 4hrs post the resistance exercise session. From each biopsy sample, we isolated individual muscle fibers. After myosin isoform identification of isolated fibers (SDS-PAGE), RNA extraction of 20 MHC I and 20 MHC IIa muscle fibers per biopsy sample followed. Thus, each resulting sample contained total RNA from 20 muscle fibers of identical fiber type (MHC I or MHC IIa). A total of 70 samples were analyzed on separate microarray chips, and samples were not pooled between subjects. The study design allowed us to examine the acute effects of resistance exercise on the transcriptome in MHC I and MHC IIa muscle fibers in the untrained and trained state. Less...