In vitro effects of nanoparticles on osteoblasts differentiation in microgravity

Exposure to microgravity has been associated with several physiological changes in astronauts, including an osteoporosis-like loss in bone mass. Osteoporosis is a disease of bones which leads to high risk of fractures and other problems, mainly due to the reduction of the bone mineral density. The lack of weight-bearing forces makes microgravity an ideal physical stimulus to assess bone cell responses. In this study we aimed to determine the effects of nanoparticles as contromeasure to micro-gravity induced osteoporosis on osteoblast cells. Nanoparticles of hydroxyapatite (nHaps) and strontium-enriched hydroxyapatite (Sr-nHaps) were obtained by power dispersion in bovine serum albumin. Physical-chemical characterization of nHAP and Sr-nHAP measuring hydrodynamic radius, z-potential and taking images a transmission electron microscope observation (TEM). Biological studies were performed in vitro by evaluating osteoblast viability and calcium deposition in the presence/absence of simulated microgravity with or without both type of nanoparticles. The results show that osteoblast viability like as calcium deposition were increased by treatment with Sr-nHAPs in simulated microgravity if compared to the untreated or untreated cells with nHAPs. Whole these preliminary data seems to suggest that these nanoparticles could be a useful system for the delivery of strontium for the treatment of osteoporosis in simulated microgravity.