Dylan Holly, M.Ed.
Skeletal muscle is a complex tissue and while its primary job is to assist in movement, this is not its sole purpose. Muscle is also a major storehouse for energy in the form of amino acids and metabolic machinery responsible for much of our daily energy expenditure. The energy cost of muscle comes with a price. When subjected to an unloaded state such as bed-rest, immobilization, or microgravity, the muscle atrophies. In other words, the cross-sectional area diminishes and with this comes a decrease in force production. You may have noticed when a cast is removed from a broken limb that the arm or leg is much smaller than its counterpart.
It makes sense that if something is energetically costly and not being used then it would be wise to get rid of it. Our bodies are smart enough to do just this and when sensors respond to extended periods of disuse they begin to take apart this expensive machinery. This is accomplished through a cascade of cellular events that lead to protein degradation. However, this presents problems in the real world when it comes to rehabilitation and so the aim of this study is to look at a possible mechanism by which to prevent some of this muscle loss.
Our lab has shown a causal role that reactive oxygen species (ROS) play in starting and maintaining this atrophy process. ROS are generated through metabolic and chemical reactions in the body and are normally referred to as free radicals in the general population. Disuse results in a spike of ROS and this causes movement of an enzyme nNOS (neuronal nitric oxide synthase) from the cell membrane to the interior of the cell. This movement of a molecule that normally resides at the cell membrane sets off a cascade of intracellular events that lead to the breakdown of the muscle cell. Our interventions of fish oil and curcumin aim at scavenging these excess ROS. By dealing with the high levels of ROS we can mitigate the cellular processes that lead to muscle breakdown and preserve muscle mass. It’s also important to note that these two interventions have been shown to diminish muscle atrophy when used alone and our lab wanted to see if combining both treatments would result in a more profound “rescue effect.” This intervention experiment is also important because many drugs created to combat muscle atrophy are quite expensive and often times have negative side effects. Fish oil and curcumin are not toxic and are easily available to any average person shopping at the local Wal-Mart.