No abstract

No abstract

No abstract

Parathyroid hormone (1-34, PTH) combined β-tricalcium phosphate (β-TCP) achieves stable bone regeneration without cell transplantation in previous studies. Recently, with the development of tissue engineering slow release technology, PTH used locally to promote bone defect healing become possible. This study by virtue of collagen with a combination of drugs and has a slow release properties, and investigated bone regeneration by β-TCP/collagen (β-TCP/COL) with the single local administration of PTH. After the creation of a rodent critical-sized femoral metaphyseal bone defect, β-TCP/COL was prepared by mixing sieved granules of β-TCP and atelocollagen for medical use, then β-TCP/COL with dripped PTH solution (1.0 µg) was implanted into the defect of OVX rats until death at 4 and 8 weeks. The defected area in distal femurs of rats was harvested for evaluation by histology, micro-CT, and biomechanics. The results of our study show that single-dose local administration of PTH combined local usage of β-TCP/COL can increase the healing of defects in OVX rats. Furthermore, treatments with single-dose local administration of PTH and β-TCP/COL showed a stronger effect on accelerating the local bone formation than β-TCP/COL used alone. The results from our study demonstrate that combination of single-dose local administration of PTH and β-TCP/COL had an additive effect on local bone formation in osteoporosis rats.

No abstract

Previous studies have demonstrated the effect of human parathyroid hormone (1-34) (PTH) or strontium-doped hydroxyapatite coating (Sr-HA) on osteoporotic bone implantation. However, reports about effects of PTH plus Sr-HA on bone osseointegration of titanium implants in a state of osteoporosis were limited. This study was designed to investigate the effects of intermittent administration of human parathyroid hormone (1-34) on strontium-doped hydroxyapatite coating (Sr-HA) implant fixation in ovariectomized (OVX) rats. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into four groups including control group, Sr group, PTH group and PTH+Sr group. Forty OVX rats accepted implant insertion in the distal femurs, control group, and PTH group with HA implants and the Sr group and PTH+Sr group with Sr-HA implants. Animals from PTH group and PTH+Sr group then randomly received PTH (60 µg/kg, 3 times a week) until death at 12 weeks. After 12-week healing period, implants from group PTH+Sr revealed improved osseointegration compared with other treatment groups, which is manifested by the exceeding increase of bone area ratio and bone-to-implant contact, the trabecular microarchitecture and the maximal push-out force displayed by tests like histomorphometry, micro-CT, and biomechanics evaluation. These results demonstrated that PTH+ Sr-HA coatings could enhance implant osseointegration in OVX rats, and suggested the feasibility of using this method to improve implant fixation in osteoporotic bone.

The objective of the present study was to incorporate strontium into calcium phosphate cement combined with a lower single-dose local administration of bone morphogenetic protein-2 to enhance its in vivo biodegradation and bone tissue growth. After the creation of a rodent critical-sized femoral metaphyseal bone defect, strontium-modified calcium phosphate cement was prepared by mixing sieved granules of calcium phosphate cement and 5% SrCO for medical use, and then strontium-modified calcium phosphate cement with dripped bone morphogenetic protein-2 solution (5 µg) was implanted into the defect of OVX rats until death at eight weeks. The defected area in distal femurs of rats was harvested for evaluation by histology, micro-CT, and biomechanics. The results of our study show that a lower single-dose local administration of bone morphogenetic protein-2 combined local usage of strontium-modified calcium phosphate cement can increase the healing of defects in OVX rats. Furthermore, treatments with single-dose local administration of bone morphogenetic protein-2 and strontium-modified calcium phosphate cement showed a stronger effect on accelerating the local bone formation than calcium phosphate cement and strontium-modified calcium phosphate cement used alone. The results from our study demonstrate that combination of a lower single-dose local administration of bone morphogenetic protein-2 and strontium-modified calcium phosphate cement had an additive effect on local bone formation in osteoporosis rats.

No abstract