Effects of combined human parathyroid hormone (1-34) and menaquinone-4 treatment on the interface of hydroxyapatite-coated titanium implants in the femur of osteoporotic rats.

The objective of this study was to investigate the effects of human parathyroid hormone (1-34) (PTH1-34; PTH) plus menaquinone-4 (vitamin K2; MK) on the osseous integration of hydroxyapatite (HA)-coated implants in osteoporotic rats. Ovariectomized female Sprague-Dawley rats were used for the study. Twelve weeks after bilateral ovariectomy, HA-coated titanium implants were inserted bilaterally in the femoral medullary canal of the remaining 40 ovariectomized rats. All animals were then randomly assigned to four groups: Control, MK, PTH and PTH + MK. The rats from groups MK, PTH and PTH + MK received vitamin K2 (30 mg/kg/day), PTH1-34 (60 µg/kg, three times a week), or both for 12 weeks. Thereafter, serum levels of γ-carboxylated osteocalcin (Gla-OC) were quantitated by ELISA and the bilateral femurs of rats were harvested for evaluation. The combination of PTH and MK clearly increased the serum levels of Gla-OC (a specific marker for bone formation) compared to PTH or MK alone. The results of our study indicated that all treated groups had increased new bone formation around the surface of implants and increased push-out force compared to Control. In addition, PTH + MK treatment showed the strongest effects in histological, micro-computed tomography and biomechanical tests. In summary, our results confirm that treatment with PTH1-34 and MK together may have a therapeutic advantage over PTH or MK monotherapy on bone healing around HA-coated implants in osteoporotic rats.

The effects of combined human parathyroid hormone (1-34) and simvastatin treatment on the interface of hydroxyapatite-coated titanium rods implanted into osteopenic rats femurs.

The effect of human parathyroid hormone 1-34 (PTH) and simvastatin (SIM) alone could promote bone healing in osteoporotic implant fixation, but there are no reports about the combined use of PTH and SIM for promotion of bone healing around implant in osteoporotic settings. This study aims to investigate effects of PTH + SIM on implant stabilization in osteopenic rats. Fourteen weeks after chronically fed a low protein diet, osteopenic rats randomly received implants. Subsequently, the animals were randomly divided into four groups: Control, SIM, PTH and PTH + SIM. Then all rats from groups PTH, SIM and PTH + SIM received PTH (40 µg/kg, three times a week), SIM (25 mg/kg, daily), or both for 12 weeks. The results of our study indicated that all treatments promoted bone healing around implant compared to Control, but PTH + SIM treatment showed significantly stronger effects than PTH or SIM alone in histological, micro-CT, and biomechanical tests. The results indicated additive effects of PTH and SIM on implant fixation in osteoporotic rats.

Combined treatment with Cinnamaldehyde and ß-TCP had an additive effect on bone formation and angiogenesis in critical size calvarial defect in ovariectomized rats.

Accumulating evidence suggests that improvements in osteogenesis and angiogenesis play an important role in repairing osteoporotic bone defects. Cinnamomum cassia (C. cassia), a traditional Chinese medicinal herb, is reported to show anabolic effects on osteoblasts. However, whether C. cassia could actually repair bone defects in osteoporotic conditions remains unknown. The purpose of this study was to evaluate the effect of combined treatment with Cinnamaldehyde (main oil isolated from the C. cassia) and ß-tricalcium phosphate (ß-TCP) on bone formation and angiogenesis in critical size calvarial defects in ovariectomized (OVX) rats. Using a previously established OVX model, 5 mm critical size calvarial defect was established in OVX rats. All OVX rats were then randomly divided into OVX group (OVX rats + empty defect), TCP group (OVX rats + ß-TCP), and CTCP group (Cinnamaldehyde 75 mg/kg/day for 12 weeks + ß-TCP). Twelve weeks after treatment, according to Micro-CT and HE staining, combination of Cinnamaldehyde and ß-TCP had an additive effect on bone regeneration compared with other groups (p < 0.05). Based on dynamic fluorochrome-labelling analysis, Cinnamaldehyde+ß-TCP continuously promoted new bone mineralization compared with other groups at each time point (p < 0.05). Microfil perfusion suggested that CTCP group showed more neovascularization compared with other groups (p < 0.05). Immunohistochemical assay supported the findings that Cinnamaldehyde+ß-TCP enhanced expression of OCN, VEGF and CD31. The present study demonstrated that combined treatment with Cinnamaldehyde and ß-TCP promoted bone formation and angiogenesis in osteoporotic bone defects, which provides a promising new strategy for repairing bone defects in osteoporotic conditions.

A comparative study of strontium-substituted hydroxyapatite coating on implant's osseointegration for osteopenic rats.

Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for the implants in cementless arthroplasty. However, its effect is not sufficient for osteoporotic bone. Strontium (Sr) promotes osteoblast proliferation and inhibits osteoclast proliferation and positively affects bone regeneration. The aim of this study was to confirm the effects of strontium-substituted hydroxyapatite (Sr-HA) coating via electrochemical deposition on implant's osseointegration in the osteoporotic condition. Female Sprague Dawley rats were used for this study. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into four groups: group HA; group 5 % Sr-HA; group 10 % Sr-HA; and group 20 % Sr-HA. Afterward, all rats from groups HA, 5 % Sr-HA, 10 % Sr-HA, and 20 % Sr-HA received implants with hydroxyapatite coating containing 0, 5, 10, and 20 % Sr. Implants were inserted bilaterally in all animals until death at 12 weeks. The bilateral femurs of rats were harvested for evaluation. All treatment groups increased new bone formation around the surface of titanium rods and push-out force; group 20 % Sr-HA showed the strongest effects on new bone formation and biomechanical strength. Additionally, these are significant differences in bone formation and push-out force was observed between groups 5 % Sr-HA and 10 % Sr-HA. This finding suggests that Sr-HA coating can improve implant osseointegration, and the 20 % Sr coating exhibited the best properties for implant osseointegration among the tested coatings in osteoporosis rats.

A comparative study of zinc, magnesium, strontium-incorporated hydroxyapatite-coated titanium implants for osseointegration of osteopenic rats.

Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for the implants in cementless arthroplasty. However, its effect is not sufficient for osteoporotic bone. Zinc (Zn), magnesium (Mg), and strontium (Sr) present a beneficial effect on bone growth, and positively affect bone regeneration. The aim of this study was to confirm the different effects of the fixation strength of Zn, Mg, Sr-substituted hydroxyapatite-coated (Zn-HA-coated, Mg-HA-coated, Sr-HA-coated) titanium implants via electrochemical deposition in the osteoporotic condition. Female Sprague-Dawley rats were used for this study. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into four groups: group HA; group Zn-HA; group Mg-HA and group Sr-HA. Afterwards, all rats from groups HA, Zn-HA, Mg-HA and Sr-HA received implants with hydroxyapatite containing 0%, 10% Zn ions, 10% Mg ions, and 10% Sr ions. Implants were inserted bilaterally in all animals until death at 12 weeks. The bilateral femurs of rats were harvested for evaluation. All treatment groups increased new bone formation around the surface of titanium rods and push-out force; group Sr-HA showed the strongest effects on new bone formation and biomechanical strength. Additionally, there are significant differences in bone formation and push-out force was observed between groups Zn-HA and Mg-HA. This finding suggests that Zn, Mg, Sr-substituted hydroxyapatite coatings can improve implant osseointegration, and the 10% Sr coating exhibited the best properties for implant osseointegration among the tested coatings in osteoporosis rats.