Using Dynamic Foot Pressure as a Countermeasure to Muscle Atrophy / 20-30
Mark S. F. Clarke, Charles S. Layne, Daniel A. Martinez, Daniel L. Feeback, Antonios Kyparos
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Abstract--Microgravity during space flight induces loss of skeletal muscle (SKM) mass, strength and functionality that could jeopardize the success of a mission. One animal model commonly used to mimic the effects of microgravity on skeletal muscle is the rat hindlimb unloading (HU) model. In this model, the back legs of the rat are lifted up off the ground by a harness attached to the tail of the animal. During HU, the muscles of the back legs do not support the weight of the animal and, hence, undergo muscle atrophy. The aim of this project was to investigate whether or not mechanical pressure applied to the base of the unloaded rat foot could prevent the process of SKM atrophy by increasing neuromuscular activation in the muscles of the unloaded hindlimb. Our results indicate that the application of DFP ameliorates the SKM atrophy induced by HU in the soleus muscle of the rat. It is postulated that this effect is achieved via stimulation of proprioceptive pathways as a consequence of DFP mimicking the neuromuscular activity/contraction patterns normally induced by load bearing in specific anti-gravity muscles of the lower limbs in a terrestrial environment. This underlying concept promises to serve as the basis for the development of a novel supplement to pre-existing exercise countermeasures during space flight, as well as an effective rehabilitation tool for clinical populations such as bed-ridden or elderly patients.