Purpose: To analyze the effect of 3 months of training on global gene expression in skeletal muscle of healthy elderly men in order to better characterize the pathways that differentiate the trained from the sedentary state.
Methods: Needle biopsies were obtained from the vastus lateralis of six healthy, sedentary, 68.0 +/- 2.7-yr-old males, before and after 3 months of training at 80% of maximal capacity, that improved peak O2 uptake by 17.8 +/- 4.0% (P = 0.009). RNA extracted from the samples was hybridized to Affymetrix U133A Genechip arrays.
Results: Overall, training modified the expression of 397 out of 14,500 genes tested. In the trained state, the expression of genes linked with energy metabolism, protein amino acid dephosphorylation, and heme biosynthesis increased, whereas those linked with ribosome and protein catabolism decreased.
Conclusion: This set of 397 genes that includes the upregulated energy pathways and the downregulated protein catabolism genes represents the transcriptional response of the skeletal muscle in the trained state. It is highly likely that many of these genes are mediators of the beneficial effects of physical activity on health and fitness.