The fast degradation of ß-TCP ceramics facilitates healing of bone defects by the combination of BMP-2 and Teriparatide.

Accumulating evidence suggests that the degradation and resorption of calcium phosphate ceramics is always relatively slow, which may inhibit calcium phosphate ceramics' replacement by new bone tissues and the ultimate bone defect repair. Bone morphogenetic proteins (BMPs) and Teriparatide (PTH) are extensively applied in the treatment of bone pathologies, while their effects on the degradation of calcium phosphate ceramics is limited. In this study, we tested the effects of BMP and PTH on degradation of ß-tricalcium phosphate (ß-TCP) ceramics and bone formation on ß-TCP in ovariectomized (OVX) rat models. After establishment of femur defect model on OVX rats, the BMP + PTH group's rats were injected Teriparatide (30 µg/kg) subcutaneous every other day, while rats of control group and group BMP were injected equal-to-group volume sterilized saline water. Twelve weeks after femur surgery, all rats were sacrificed for Micro-CT scanning and histology tests. The results showed that BMP facilitated degradation of ß-TCP and new bone formation on ß-TCP ceramics. And PTH showed an additional effect on degradation of ß-TCP when combined with BMP. In addition, the results explained that PTH promoted the remodeling of the bone callus occurred during repair.

Combined treatment with vitamin K2 and PTH enhanced bone formation in ovariectomized rats and increased differentiation of osteoblast in vitro.

Osteoporosis is accompanied by insufficient osteogenic capacity. Several lines of evidence suggested that solutions to enhance osteoblastogenesis were important strategies for osteoporotic bone defect repair. This study investigated the effect of combined treatment with vitamin K2 and PTH on bone formation in calvarial bone defect in osteoporotic rats and its influence on osteoblast in vitro. Bilateral ovariectomy was used in SPF Sprague Dawley rats to generate an osteoporosis model. Subsequently, a calvarial defect model was established and all osteoporotic rats were randomly assigned to the following groups: control, VK (vitamin K2, 30 mg/kg everyday), PTH (recombinant human PTH (1-34), 60 µg/kg, three times a week) or VK + PTH (vitamin K2, 30 mg/kg everyday plus PTH, 60 µg/kg three times a week) for 8 weeks. In vitro, bone marrow-derived stem cells (BMSCs) were cultured and treated with vitamin K2, PTH or vitamin K2+PTH. ALP staining and western blot were performed to observe the influence of combined treatment on BMSCs. Bone formation within calvarial defect were assessed by serum γ-carboxylated osteocalcin (Gla-OC), micro-CT, histological and immunofluorescent labeling. In this study, combined treatment of PTH and vitamin K2 showed positive effects on preventing bone loss in femurs in OVX rats. Combined treatment increased serum Gla-OC and promoted bone formation in osteoporotic calvarial bone defects. Immunohistochemistry showed that OCN and RUNX2 were more highly expressed in the VK + PTH group than in the control groups. In vitro studies results suggested that combined treatment with PTH and vitamin K2 increased expression of ALP, BMP2 and RUNX2 in BMSCs. Our data suggested that the combination of vitamin K2 and PTH increased differentiation of osteoblast and had a synergistic effect on bone formation in osteoporotic calvarial bone defect.

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.

Effects of combined menaquinone-4 and PTH1-34 treatment on osetogenesis and angiogenesis in calvarial defect in osteopenic rats.

PURPOSE: The aim of this study was to evaluate the effect of combining human parathyroid hormone (1-34) (PTH1-34; PTH) and menaquinone-4 (MK-4) on calvarial bone defect repair in osteopenic rats. METHODS: Fourteen week olds were subject to craniotomy for the establishment of osteopenic animal models fed through a chronically low-protein diet. After that, critical calvarial defect model was established and all rats were randomly divided into four groups: sham, MK-4, PTH, and PTH + MK-4. The animals received MK-4 (30 mg/kg/day), PTH1-34 (60 µg/kg, three times a week), or PTH1-34 (60 µg/kg, three times a week) plus MK-4 (30 mg/kg/day) for 8 weeks, respectively. Serum γ-carboxylated osteocalcin (Gla-OC) levels, histological and immunofluorescent labeling were employed to evaluate the bone formation and mineralization in calvarial bone defect. In addition, Microfil perfusion, immunohistochemical, and micro-CT suggested enhanced angiogenesis and bone formation in calvarial bone healing. RESULTS: In this study, treatment with either PTH1-34 or MK-4 promoted bone formation and vascular formation in calvarial bone defects compared with the sham group. In addition, combined treatment of PTH1-34 plus MK-4 increased serum level of Gla-OC, improved vascular number and vascular density, and enhanced bone formation in calvarial bone defect in osteopenic conditions as compared with monotherapy. CONCLUSIONS: In summary, this study indicated that PTH1-34 plus MK-4 combination therapy accelerated bone formation and angiogenesis in calvarial bone defects in presence of osteopenia.

Combined treatment with cinnamaldehyde and PTH enhances the therapeutic effect on glucocorticoid-induced osteoporosis through inhibiting osteoclastogenesis and promoting osteoblastogenesis.

The study was to investigate the effect of combining treatment with cinnamaldehyde and parathyroid hormone (1-34) (PTH) on glucocorticoid-induced osteoporosis (GIO) and compare with monotherapy. Forty Sprague-Dawley male rats with GIO were divided into four groups randomly: control group (CON group, N = 10); group that intragastric administration with cinnamaldehyde (CIN group, N = 10); group that subcutaneous injection with PTH, three times per week(PTH group, N = 10); both administration with cinnamaldehyde and PTH (CIN + PTH group, N = 10). Distal femurs were harvested for hematoxylin and eosin (H&E) staining, micro-CT scanning and immunohistochemical analysis. Murine mesenchymal stem cells were cultured and dealt with the presence of dexamethasone(DEX group), DEX + cinnamaldehyde(DEX + CIN group), DEX + PTH(DEX + PTH group) or DEX + cinnamaldehyde + PTH(DEX + CIN + PTH group). Alkaline phosphatase (ALP) staining was performed subsequently. The results showed that bone formation in CIN + PTH group was notably promoted compared with other groups. And the expression of tartrate-resistant acid phosphatase (trap) and runt-related transcription factor 2 (runx2) in CIN + PTH group were down-regulated and up-regulated respectively compared with PTH group. In vitro study revealed that ALP-positive cell number in DEX + CIN + PTH group was obviously enhanced compared with other groups. The study revealed that combined treatment with cinnamaldehyde and PTH enhances the therapeutic effect on GIO through inhibiting osteoclastogenesis and promoting osteoblastogenesis.

Administration of cinnamaldehyde promotes osteogenesis in ovariectomized rats and differentiation of osteoblast in vitro.

To explore the effect of cinnamaldehyde on the distal femur in ovariectomized rats and its influence on osteoblast in vitro. Female Sprague-Dawley rats which underwent either bilateral ovariectomy or sham operation were divided into five groups randomly: group OVX (OVX, N = 10) and group sham (SHAM, N = 10) received normal saline (NS) by gavage at a dose of 50 ml/kg·d; group low dose, group middle dose and group high dose received cinnamaldehyde by gavage at a dose of 25 mg/kg·d (OLD, N = 10), 50 mg/kg·d (OMD, N = 10), and 75 mg/kg·d (OHD, N = 10) respectively. Distal femurs were harvested for hematoxylin and eosin (HE) staining, micro-ct scanning and immunohistochemical analysis. Murine mesenchymal stem cells were cultured and dealt with the presence of either cinnamaldehyde at a dose of 15ug/ml (OLD), 30ug/ml (OMD), 60ug/ml (OHD) or vehicle. ALP staining and western blot were performed to observe the influence of cinnamaldehyde on the differentiation of osteoblast. HE and micro-ct results indicated that osteogenesis were promoted with the treatment of cinnamaldehyde. Immunohistochemical results showed that cinnamaldehyde increased the number of osteoblast and decreased the number of osteoclast. In vitro studies indicated that cinnamaldehyde promoted expression of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and collagen type Iɑ1 (COL1ɑ1). The treatment effect behaved as dose-dependently. Thus, cinnamaldehyde inhibits osteoclastogenesis and promotes osteoblastogenesis, and may plays an important role in the treatment of osteoporosis clinically.

Chitosan oligosaccharide promotes osteoclast formation by stimulating the activation of MAPK and AKT signaling pathways.

Chitosan Oligosaccharide (COS) has been widely used for the systemic treatment of clinical diseases such as bone tissue engineering. However, its influence on osteoclast formation, which plays a critical role in bone homeostasis, has never been investigated. The aim of this study was to investigate the effect of chitosan oligosaccharide on differentiation of osteoclast. Using cell counting kit-8, tartrate-resistant acid phosphatase staining, reverse transcription­quantitative polymerase chain reaction assay and western blot analysis, we demonstrated that chitosan oligosaccharide cannot inhibit RANKL-induced osteoclast precursor proliferation but does promote osteoclast differentiation by stimulating the activation of p38/mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK)/MAPK, extracellular signal-regulated kinase (ERK)/MAPK and protein kinase B (AKT) without affecting nuclear factor kappaB (NF-kB) signaling pathways. Based on the promoting effect of chitosan oligosaccharide on osteoclast differentiation, we suggest that this property of chitosan oligosaccharide may have potential detrimental effect on bone homeostasis.

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.

Teriparatide promotes healing of critical size femur defect through accelerating angiogenesis and degradation of ß-TCP in OVX osteoporotic rat model.

Accumulating evidence suggests that early angiogenesis has an important effect on the healing of injury. Teriparatide (PTH) is extensively applied for its potent anabolic activity on bone, while little is known about its angiogenic ability which may facilitate new bone formation. In this study, we tested the angiogenic ability of PTH and its effect on degradation of ß-tricalcium phosphate (ß-TCP) in an ovariectomized (OVX) rat distal femoral metaphysis model. After successful establishment of the OVX model was confirmed, a critical size defect was drilled into each distal femur of the OVX rats. Afterwards all animals were randomly divided into three groups: control group, group ß-TCP and group ß-TCP+PTH, then rats of group ß-TCP+PTH were injected Teriparatide (30 µg/kg) subcutaneous every other day. Four weeks after femur surgery, five specimens from each group were used for Microfil perfusion to reveal blood vessels in the bone defect. The residual rats were harvested for micro-computed tomography, histological analysis and immunochemistry. The results showed Teriparatide facilitated neovascularization, degradation of ß-TCP and new bone formation in combination with ß-TCP, which may be relevant to neovascularization in an early phase.