(62at) Experimental Study of Simulated Weightlessness in Model Bone Systems

Past astronauts have lost up to 13% of their bone mass during space missions according to NASA and can lose up to 2% of their bone mass each month. Recent research on bone loss in the literature involves the evaluation and analysis of microgravity and its effects on humans, mice, and other animals. Gravitational effects on earth-based skeletal development influences the size, shape, strength of bone, the vascular supply, and fluid flow to the skeletal system. Gravity also provides the mechanical stimulus necessary for bone growth, development, and maintenance. Past astronauts have lost up to 13% of their bone mass during missions in space according to NASA and can lose up to 2% of their bone mass each month.

Previous work determined the effects of simulated microgravity on weight gain, feed and water intake, urine and fecal output, and bone decomposition in rats in an effort to further understand of the treatment of osteoporosis in human patients. Development of a test model at North Carolina A&T State University was carried out in partnership with NASA-Ames Research Center to study the effects of weightlessness for future manned space missions. An experimental model to study simulated weightlessness in Sprague Dawley Rats was developed to gain further understanding of the physiological phenomena that occur in a microgravity environment. A model replica was made of the NASA Morley-Holton cage for weightlessness referred to as the Micro-Gravitational Metabolic Cage (MGMC). Non-weight bearing versus weight bearing conditions were studied over a 42-day period. Weight gain, urine and fecal output were observed to be moderately affected in the non-weight bearing rats. The water and feed intake were observed to be similar in both groups.

Several environmentally benign and biocompatible model systems such as smectite clays, layered double hydroxides, hydroxyapatite, and swelling synthetic micas will be employed as the inorganic matrix for the synthesis of biopolymer nanocomposite materials. These synthesized bionanocomposites will be exposed to model microgravity conditions for bone demineralization and characterized before and after exposure using XRD, SEM, TEM and elemental analysis. The experimental data will be compared with previously obtained experimental and literature data for bone loss in rats and humans.