Influence of Local Muscle Cooling on Mitochondrial-Related Gene Expression

Background: Mitochondrial health is an important factor for preventing disease and optimizing function. Exercise promotes mitochondrial related gene expression in skeletal muscle, specifically upregulated PGC-1α, the master regulator of mitochondrial biogenesis. Additionally, previous studies suggest exercise in cold ambient temperatures can elevate mitochondrial biogenesis gene expression; however, others demonstrate a blunted gene expression when applied to a local area (i.e., vastus lateralis). More importantly, the mitochondrial effects of cooling a muscle at rest is unknown. Purpose: The purpose of this study is to apply localized cooling to the vastus lateralis at rest to examine gene expression related to mitochondrial homeostasis. Methods: A total of 12 apparently healthy individuals (age 19-45) will sit with a cold (0°C) wrap on one leg and a room temperature (21°C) wrap on the other leg (control). After a 4-hour cold treatment, the thermal wraps will be removed, and measurements will be collected for blood flow, skin temperature, intramuscular muscle temperature and a Bergstrom muscle biopsy will be obtained. This biopsy will be used to analyze transcriptional changes of genes associated with mitochondrial growth (biogenesis) and breakdown (mitophagy). Implications: These results will help put in perspective previous research, which evaluated ambient and local cold therapies during exercise, by eliminating the exercise effect. Finally, this study will contribute to a better understanding of how local cold application will affect mitochondria health in skeletal muscle and to the potential development of therapeutic applications