Expression data from rat skeletal muscle. Rattus norvegicus

We used old (~96-102 weeks of age) and young (~28-34 weeks of age) rats from HCR and LCR generations 29 and 32, respectively. The study included eight groups; HCR-Old-Exhausted (H-O-E, n=6), HCR-Old-Rest (H-O-R, n=6), HCR-Young-Exhausted (H-Y-E, n=6), HCR- Young -Rest (H-Y-R, n=6), LCR-Old-Exhausted (L-O-E, n=6), LCR-Old-Rest (L-O-R, n=6), LCR-Young-Exhausted (L-Y-E, n=6), and LCR- Young -Rest (L-Y-R, n=6). For the exhausted rats, dissections were performed within 10 min after the maximal running distance was reached. We extracted skeletal muscle RNA from a total of 48 female animals (n=6 in each of the 8 group). Skeletal muscle tissue was obtained from the Extensor digitorum longus (EDL). All rats were dissected immediately after sacrificing, and all tissue samples were immediately weighed and snap frozen in liquid nitrogen, and stored at -80 ºC. Total RNA was extracted from frozen tissue with Trizol reagent (Invitrogen, Carlsbad, CA), treated with DNase-free (Invitrogen, Carlsbad, CA) and cleaned up with RNeasy columns (Qiagen, Hilden, Germany) Overall design: We ran the skeletal muscle RNA on the Affymetrix Rat Gene ST 2.1 array. The microarray hybridizations were performed by the DNA sequencing Core at the University of Michigan according to the manufacturer’s instructions. We used the Affymetrix Expression ConsoleTM software to generate gene expression values from individual probe intensity (CEL) files. The microarray measures a total of 19,607 transcripts based on the Refseq database.