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 a high risk of fracture 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 [1]. In this study, we aimed to determine the effect of nanoparticles as a countermesasure to microgravity-induced osteoporosis on osteoblasts cells. Materials and Methods Materials: powders of hydroxyapatite (HAP) and HAP enriched with Sr (HAP-Sr) were synthetized by sol-gel method. Hydroxyapatites powders were firstly characterized by ICP, XRD, N2 sorption, SEM and TEM analysis. Nanoparticles: HAPs and HAP-Sr were dispersed in Bovine Serum Albumin (BSA) and treated by ultrasound sonication. Nanoparticles characterization: nanoparticles were characterized by using FT-IR to investigate the interaction between materials and BSA, by dynamic light scattering (DLS) to study hydrodynamic radius, by Z-potential for the surface charges and by TEM to measure size and visualize the shape. Cells: Human osteosarcoma cell line SAOS-2 was obtained from the American Type Culture Collection. Cells were cultured in completed McCoy's 5A modified medium and treated with nanoparticles suspensions for 1, 3 and 7 days changing medium two times per week. Untreated cells were used as control. Cell viability: Using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test (Sigma-Aldrich), viability of treated and untreated cells was evaluated after 1, 3 and 7 days of culture and results were expressed as percentage related to control. Cell morphology: To investigate cell morphology, after 1 and 7 days cells were fixed with glutaraldehyde, dehydrated with alcohol and observed using Scanning Electron Microscope (SEM). Results The size of the nanoparticles measured by DLS is around 100 nm. Higher values were observed for the nHAPs enriched with Sr ( nHAP-SR) due to the greater atomic radius of Strontium if compared to Calcium. The FT-IR spectra shows the modifications of the amino-groups bands of the protein and phosphate groups of HAP, suggesting an interaction at the molecular level of these groups. After 1, 3 and 7 days of nanoparticles treatment,cell viability results reveal an effect of nHAP-Sr on cell proliferation that was 35% higher than control (p<0.05). No statistical differences were observed between nHAPs treated cells and control. In SEM observations, cells show typical morphology of SAOS-2 cell line and no differences were observed between treated and untreated cells.

In vitro effects of nanoparticles on bone remodelling in microgravity

Pascucci B;Rea G;
2015

Abstract

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 a high risk of fracture 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 [1]. In this study, we aimed to determine the effect of nanoparticles as a countermesasure to microgravity-induced osteoporosis on osteoblasts cells. Materials and Methods Materials: powders of hydroxyapatite (HAP) and HAP enriched with Sr (HAP-Sr) were synthetized by sol-gel method. Hydroxyapatites powders were firstly characterized by ICP, XRD, N2 sorption, SEM and TEM analysis. Nanoparticles: HAPs and HAP-Sr were dispersed in Bovine Serum Albumin (BSA) and treated by ultrasound sonication. Nanoparticles characterization: nanoparticles were characterized by using FT-IR to investigate the interaction between materials and BSA, by dynamic light scattering (DLS) to study hydrodynamic radius, by Z-potential for the surface charges and by TEM to measure size and visualize the shape. Cells: Human osteosarcoma cell line SAOS-2 was obtained from the American Type Culture Collection. Cells were cultured in completed McCoy's 5A modified medium and treated with nanoparticles suspensions for 1, 3 and 7 days changing medium two times per week. Untreated cells were used as control. Cell viability: Using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test (Sigma-Aldrich), viability of treated and untreated cells was evaluated after 1, 3 and 7 days of culture and results were expressed as percentage related to control. Cell morphology: To investigate cell morphology, after 1 and 7 days cells were fixed with glutaraldehyde, dehydrated with alcohol and observed using Scanning Electron Microscope (SEM). Results The size of the nanoparticles measured by DLS is around 100 nm. Higher values were observed for the nHAPs enriched with Sr ( nHAP-SR) due to the greater atomic radius of Strontium if compared to Calcium. The FT-IR spectra shows the modifications of the amino-groups bands of the protein and phosphate groups of HAP, suggesting an interaction at the molecular level of these groups. After 1, 3 and 7 days of nanoparticles treatment,cell viability results reveal an effect of nHAP-Sr on cell proliferation that was 35% higher than control (p<0.05). No statistical differences were observed between nHAPs treated cells and control. In SEM observations, cells show typical morphology of SAOS-2 cell line and no differences were observed between treated and untreated cells.
2015
Istituto di Cristallografia - IC
microgravity
osteoporosis
nanoparticles
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/332589
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