Introduction
Re-programming of gene expression is fundamental for skeletal muscle adaptations in response to endurance exercise. Although inflammatory responses in muscle following muscle-damaging exercise can persist for days, there is a paucity of global gene expression data beyond 48 hours following exercise. This study aimed to investigate the changes in the transcriptome of skeletal muscle until 96 hours after an endurance exercise trial (EXTRI; one hour of cycling followed by one hour of running). Data on the transcriptome of circulating neutrophils from participants in the current study indicated that the neutrophil transcriptional activity was related to the muscle-damaging component of the EXTRI (Neubauer et al. 2013, J Appl Physiol.). We hypothesised that the muscular transcriptome would particularly reflect interactions between muscle and infiltrating leukocytes.
Methods
Eight healthy, endurance-trained, male individuals participated. Skeletal muscle samples were taken one week before the EXTRI, 3, 48, and 96 hours post-EXTRI. RNA was extracted from muscle tissue. Differential gene expression was evaluated using Illumina microarrays, and validated with q-PCR. Gene set enrichment analysis identified functionally related gene sets chosen from the Molecular Signatures Database.
Results
Significantly (FWER p-value
Conclusions
The current data indicate that many of the coordinated gene expression responses in skeletal muscle, particularly at 96 hours post-EXTRI, were related with exercise-induced muscle damage, and the subsequent accumulation of muscle leukocytes. The substantial transcriptional activity 96 h post-EXTRI was strongly associated with inflammatory and immune responses, and suggests that muscular recovery, from a transcriptional perspective, is incomplete 96 hours after exercise
