Rachel Botchlett, M.S.
Skeletal muscle is a highly specialized tissue that is responsible for voluntary motion and plays a significant role in glucose metabolism and maintaining postural support. The loss of skeletal muscle, defined as atrophy, is characterized by a marked reduction in muscle protein synthesis coupled with an increase in protein degradation and can lead to a loss of contractile force. Muscular atrophy can be caused by several health issues, including starvation, aging, and muscular dystrophies, and is significantly increased in mechanical unloading (e.g. bedrest and spaceflight). As such, preventive treatments or exercise regimens to reduce atrophy are of utmost importance. Several interventional therapies have already been discovered; however, no treatments to date are completely successful in reversing or preventing atrophy. Therefore, there is a need for more efficient and effective countermeasures. One such approach may be the use of combination therapies, which utilize two or more drugs, nutrients, or interventions in combination with each other. This type of treatment may be especially beneficial to reduce atrophy in hindlimb unloading studies.
Hindlimb unloading is a common research model used to simulate bed rest or conditions similar to spaceflight. Experimental animals are put in casts or harnesses that immobilize their hind legs. This model lets researchers study muscle atrophy because they can monitor the development and subsequent reduction in atrophy after various treatments or interventions. One type of treatment used with this model involves dietary interventions using antioxidant or protein supplements. Recently, researchers have also begun to focus on the beneficial effects of fish oil.
Fish oils, specifically n-3 (also known as omega-3) polyunsaturated fatty acids, have recently been shown to reduce muscle atrophy caused by hindlimb unloading. Fish oils are believed to prevent two specific cellular changes (muscle protein translocation (i.e. movement) and cell-signaling disruption), both of which occur with atrophy. Curcumin, found in the spice turmeric, has also recently been shown to help reduce skeletal muscle atrophy. Specifically, curcumin reduces the activation of nuclear factor kappa Beta which increases inflammation in response to stress. When activated, nuclear factor kappa Beta increases protein degradation. Both fish oils and curcumin have been tested in hindlimb unloading studies; however, none are known to have used them together in skeletal muscle. Therefore, it is possible that a treatment combining fish oil and curcumin would be stronger in reducing unloading-induced skeletal muscle atrophy than either treatment alone because they target two independent pathways. Beneficial outcomes of this combination treatment could potentially lead to the development of clinical interventions to reduce or prevent atrophy in patients on bed rest.
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