Treatment study of distal femur for parathyroid hormone (1-34) and β-tricalcium phosphate on bone formation in critical-sized defects in osteopenic rats

Increased bone mass but delayed mineralization: in vivo and in vitro study for zoledronate in bone regeneration

BACKGROUND

Bisphosphonates (BPs) are widely used to inhibit excessive osteoclast activity. However, the potential to compromise bone defect healing has limited their broader application. To better understand the influence of BPs on bone regeneration, we established a bone grafting model with Zoledronate administration, aiming to deepen the understanding of bone remodeling and mineralization processes.

METHODS

A bone grafting model was established in the distal femurs of male Sprague-Dawley rats. The experimental group received systemic administration of Zoledronate (ZOL, 0.2 mg/kg, administered twice). Histological analysis and immunohistochemistry (IHC) were employed to assess osteoblastic and macrophage activity, tartrate-resistant acid phosphatase (TRAP) staining was used to evaluate osteoclastogenesis. Mineralization was assessed through Micro-CT analysis, Raman spectroscopy, and back-scatter scanning electron microscopy (BSE-SEM). Additionally, the in vitro effects of ZOL on osteoblast and osteoclast activity were investigated to further elucidate its impact on bone regeneration.

RESULTS

In vivo, the ZOL group showed increased bone mass, as observed in histological and radiological assessments. However, Micro-CT, Raman spectroscopy, and BSE-SEM detection revealed lower mineralization levels in ZOL group's regenerated bone. Acid-etched SEM analysis showed abnormal osteocyte characteristics in ZOL-group's regenerated bone. Simultaneously, elevated osteopontin (OPN), F4/80 expression along with reduced TRAP expressing was found in the grafting region of ZOL group. In vitro, ZOL did not negatively impact osteogenetic activity (ALP, BMP4, OCN expression) at the tested concentrations (0.02-0.5 g/ml) but significantly impaired mineralization and inhibited osteoclast formation, even at the lowest concentration.

CONCLUSIONS

This study highlights a less recognized negative effect of ZOL on bone mineralization during bone regeneration. More research is needed to elucidate the underlying mechanism.

In-silico study of type 'B' condylar head fractures and evaluating the influence of two positional screw distance in two-screw osteosynthesis construct

Clinical fixation screws are common in clinical practices to fix mandibular condyle fractures. Evidence suggests significance of 'working length' that is, distance between proximal and distal fixation screws in proximity to the fracture in orthopaedic implant design. In pursuit of stable implant-bone construct, this study aims to investigate the biomechanical performance of each configuration considered in the study and provide an optimal working length between the screws for clinical reference. Finite element models of virtually designed broken condyle as type 'B' were simulated and analysed in ANSYS Workbench. Screws are implanted according to previous literature at five varied distances 'd' maintaining five different ratios with the fracture length 'D'. Based on a literature review, boundary conditions, muscle traction forces and non-linear contacts were assigned to obtain precise results. Each case is considered an individual configuration and von Mises distribution, microstrain in bone, screw-bone interface micromotion and fracture dislocation were evaluated for all these configurations. Stress-shielding phenomenon is observed for maximum von Mises stresses in bone. Microstrain concentration was significant in cancellous bone in the vicinity of the screw around the fracture line. Configurations were compared based on the stress-strain along with micromotion to support the required amount of osseointegration between implant and bone. Presented data from all five conditions supported the assumption that under physiological loading conditions, the D3 configuration provided stability for fracture healing. Further research on screw shapes, diameters and material properties, or investigating the direction of forces within the screws could provide further insight into this topic.

Magnesium Ions Promote In Vitro Rat Bone Marrow Stromal Cell Angiogenesis Through Notch Signaling

Bone defects are often caused by trauma or surgery and can lead to delayed healing or even bone nonunion, thereby resulting in impaired function of the damaged site. Magnesium ions and related metallic materials play a crucial role in repairing bone defects, but the mechanism remains unclear. In this study, we induced the angiogenic differentiation of bone marrow stromal cells (BMSCs) with different concentrations of magnesium ions. The mechanism was investigated using γ-secretase inhibitor (DAPT) at different time points (7 and 14 days). Angiogenesis, differentiation, migration, and chemotaxis were detected using the tube formation assay, wound-healing assay, and Transwell assay. Besides, we analyzed mRNA expression and the angiogenesis-related protein levels of genes by RT-qPCR and western blot. We discovered that compared with other concentrations, the 5 mM magnesium ion concentration was more conducive to forming tubes. Additionally, hypoxia-inducible factor 1 alpha (Hif-1α) and endothelial nitric oxide (eNOS) expression both increased (p < 0.05). After 7 and 14 days of induction, 5 mM magnesium ion group tube formation, migration, and chemotaxis were enhanced, and the expression of Notch pathway genes increased. Moreover, expression of the Notch target genes hairy and enhancer of split 1 (Hes1) and Hes5 (hairy and enhancer of split 5), as well as the angiogenesis-related genes Hif-1α and eNOS, were enhanced (p < 0.05). However, these trends did not occur when DAPT was applied. This indicates that 5 mM magnesium ion is the optimal concentration for promoting the angiogenesis and differentiation of BMSCs in vitro. By activating the Notch signaling pathway, magnesium ions up-regulate the downstream genes Hes1 and Hes5 and the angiogenesis-related genes Hif-1α and eNOS, thereby promoting the angiogenesis differentiation of BMSCs. Additionally, magnesium ion-induced differentiation enhances the migration and chemotaxis of BMSCs. Thus, we can conclude that magnesium ions and related metallic materials promote angiogenesis to repair bone defects. This provides the rationale for developing artificial magnesium-containing bone materials through tissue engineering.

Deferoxamine/magnesium modified β-tricalcium phosphate promotes the bone regeneration in osteoporotic rats

Recently, Deferoxamine (DFO) and magnesium (Mg) have been identified as critical factors for angiogenesis and bone formation. However, in current research studies, there is a lack of focus on whether DFO plus Mg can affect the regeneration of β-tricalcium phosphate (β-TCP) in osteoporosis and through what biological mechanisms. Therefore, the present work was aimed to preparation and evaluate the effect of Deferoxamine/magnesium modified β-tricalcium phosphate promotes (DFO/Mg-TCP) in ovariectomized rats model and preliminary exploration of possible mechanisms. The MC3T3-E1 cells were co-cultured with the exudate of DFO/Mg-TCP and induced to osteogenesis, and the cell viability, osteogenic activity were observed by Cell Counting Kit-8(CCK-8), Alkaline Phosphatase (ALP) staining, Alizarin Red Staining (RES) and Western Blot. In vitro experiments, CCK-8, ALP and ARS staining results show that the mineralization and osteogenic activity of MC3T3-E1increased significantly after intervention by DFO/Mg-TCP, as well as a higher levels of protein expressions including VEGF, OC, Runx-2 and HIF-1α. In vivo experiment, Micro-CT and Histological analysis evaluation show that DFO/Mg-TCP treatment presented the stronger effect on bone regeneration, bone mineralization and biomaterial degradation, when compared with OVX+Mg-TCP group and OVX+TCP group, as well as a higher VEGF, OC, Runx-2 and HIF-1α gene expression. The present study indicates that treatment with DFO/Mg-TCP was associated with increased regeneration by enhancing the function of osteoblasts in an OVX rat.

Aspirin modified strontium-doped β-tricalcium phosphate can accelerate the healing of femoral metaphyseal defects in ovariectomized rats

The purpose was to observe whether local administration Strontium (Sr) and Aspirin (Asp) can enhance the efficacy of β-Tricalcium phosphate(β-TCP) in the treatment of osteoporotic bone defect. The MC3T3-E1 cells were co-cultured with β-TCP, Sr/β-TCP, Asp-Sr/β-TCP scaffold and induced to osteogenesis, and the cell viability, mineralization ability were observed by MTT, Alizarin Red staining(ARS) and Western blotting(WB). Then this scaffolds were implanted into the femoral epiphysis bone defect model of ovariectomized(OVX) rats for 8 weeks. X-ray, Micro-CT, histology and Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis were used to observe the therapeutic effect and explore the possible mechanism. MTT, ARS results show that the cell mineralization and viability of Asp-Sr/β-TCP group is significantly higher than Control group, β-TCP group and Sr/β-TCP group. Protein expression show that the osteogenic protein expression such as ALP、OP、RUNX-2、OC and COL-1 of Asp-Sr/β-TCP group is significantly higher than Control group, β-TCP group and Sr/β-TCP group. X-ray images, Micro-CT and Histological analysis evaluation show that, group Asp-Sr/β-TCP presented the strongest effect on bone regeneration and bone mineralization, when compared with β-TCP group and Sr/β-TCP group. RT-qPCR analysis show that Asp-Sr/β-TCP, β-TCP group and Sr/β-TCP group showed increased BMP2, Smad1, OPG than the OVX group(p < 0.05), while Asp-Sr/β-TCP exhibited decreased TNF-α、IFN-γ and RANKL than the OVX group(p < 0.05). Our current study demonstrated that Asp-Sr/ β-TCP is a scheme for rapid repair of femoral condylar defects, and these effects may be achieved by inhibiting local inflammation and through BMP-2/Smad1 and OPG/RANKL signaling pathway.

In vitro and in vivo proves of concept for the use of a chemically cross-linked poly(ester-urethane-urea) scaffold as an easy handling elastomeric biomaterial for bone regeneration

Bone loss can occur as a result of various pathologies, traumas and injuries and poor bone healing leads to functionally debilitating condition, loss of self-sufficiency and deterioration in life quality. Given the increasing incidence of facial trauma and the emergence of new procedural techniques, advanced scaffolds are currently developed as substitutes for bone tissue engineering. In this study, we investigated the capability of a chemically cross-linked ε-caprolactone-based poly(ester-urethane-urea) (PCLU) scaffold to support bone regeneration. In vitro assays demonstrated that PCLU scaffolds could be colonized by cells through direct cell seeding and cell migration from outside to scaffold inside. Moreover, PCLU scaffolds could provide a suitable environment for stem cells proliferation in a 3D spatial arrangement, and allowed osteogenic differentiation under appropriate induction. In vivo results revealed the osteogenic properties of PCLU scaffolds through a drilled-hole femoral bone defect repair improvement in rats. Using histology and microtomography analysis, we showed that PCLU scaffolds fit well the bone cavity and were eventually entrapped between the newly formed trabeculae. Finally, no sign of inflammation or rejection was noticed. We envision that PCLU scaffolds can provide the clinicians with a substitute having appropriate characteristics for the treatment of bone defects.

Local administration of aspirin with β-tricalcium phosphate/poly-lactic-co-glycolic acid (β-TCP/PLGA) could enhance osteoporotic bone regeneration

Composite materials β-tricalcium phosphate (β-TCP) and poly-lactic-co-glycolic acid (PLGA) have achieved stable bone regeneration without cell transplantation in previous studies. Recent research shows that aspirin (ASP) has great potential in promoting bone regeneration. The objective of the present study was to incorporate PLGA into β-TCP combined with a lower single-dose local administration of ASP to enhance its in vivo biodegradation and bone tissue growth. After the creation of a rodent critical-sized femoral metaphyseal bone defect, PLGA -modified β-TCP (TP) was prepared by mixing sieved granules of β-TCP and PLGA (50:50, v/v) for medical use, then TP with dripped 50 µg/0.1 ml and 100 µg/0.1 ml aspirin solution was implanted into the defect of OVX rats until death at 8 weeks. The defected area in distal femurs of rats was harvested for evaluation by histology, micro-CT, biomechanics and real time RT-PCR. The results of our study show that a single-dose local administration of ASP combined with the local usage of TP can increase the healing of defects in OVX rats. Single-dose local administration of aspirin can improve the transcription of genes involved in the regulation of bone formation and vascularization in the defect area, and inhibits osteoclast activity. Furthermore, treatments with a higher single-dose local administration of ASP and TP showed a stronger effect on accelerating the local bone formation than while using a lower dose of ASP. The results from our study demonstrate that the combination of a single-dose local administration of ASP and β-TCP/PLGA had an additive effect on local bone formation in osteoporosis rats, and bone regeneration by PLGA/β-TCP/ASP occured in a dose-dependent manner.

Osteoporotic Bone Recovery by a Highly Bone-Inductive Calcium Phosphate Polymer-Induced Liquid-Precursor

Osteoporosis is an incurable chronic disease characterized by a lack of mineral mass in the bones. Here, the full recovery of osteoporotic bone is achieved by using a calcium phosphate polymer-induced liquid-precursor (CaP-PILP). This free-flowing CaP-PILP material displays excellent bone inductivity and is able to readily penetrate into collagen fibrils and form intrafibrillar hydroxyapatite crystals oriented along the c-axis. This ability is attributed to the microstructure of the material, which consists of homogeneously distributed ultrasmall (≈1 nm) amorphous calcium phosphate clusters. In vitro study shows the strong affinity of CaP-PILP to osteoporotic bone, which can be uniformly distributed throughout the bone tissue to significantly increase the bone density. In vivo experiments show that the repaired bones exhibit satisfactory mechanical performance comparable with normal ones, following a promising treatment of osteoporosis by using CaP-PILP. The discovery provides insight into the structure and property of biological nanocluster materials and their potential for hard tissue repair.

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) (PTH_1-34; 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), PTH_1-34 (60 μg/kg, three times a week), or PTH_1-34 (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 PTH_1-34 or MK-4 promoted bone formation and vascular formation in calvarial bone defects compared with the sham group. In addition, combined treatment of PTH_1-34 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 PTH_1-34 plus MK-4 combination therapy accelerated bone formation and angiogenesis in calvarial bone defects in presence of osteopenia.

Single-dose local administration of parathyroid hormone (1-34, PTH) with β-tricalcium phosphate/collagen (β-TCP/COL) enhances bone defect healing in ovariectomized rats

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.

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.

Effects of strontium-modified calcium phosphate cement combined with bone morphogenetic protein-2 on osteoporotic bone defects healing in rats

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% SrCO3 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.

The effects of sclerostin antibody plus parathyroid hormone (1-34) on bone formation in ovariectomized rats

Previous studies have demonstrated the effects of sclerostin antibody (Scl-Ab) and parathyroid hormone (1-34, PTH) on healing in osteoporosis; however, reports about the combined effects of Scl-Ab plus PTH on osteoporosis are limited. This study was designed to investigate the impact of combined treatment with Scl-Ab and PTH on osteoporosis healing in ovariectomized (OVX) rats. After bilateral ovariectomy, 12 weeks were allowed to pass for the establishment of standard conditions for osteoporosis in animal models. The rats then randomly received a vehicle (control), Scl-Ab (25 mg/kg body weight, twice weekly), PTH (60 μg/kg, three times per week) or PTH plus Scl-Ab until death at 12 weeks. The blood and distal femurs of the rats were harvested for evaluation. The results of treatment for osteoporosis were evaluated by serum analysis, histology, microcomputed tomography (micro-CT) and biomechanical tests. Results from this study indicated that PTH + Scl-Ab had stronger effects on the prevention and treatment of osteoporosis than either of the monotherapies in OVX rats. The PTH + Scl-Ab produced the strongest effects on bone volume fraction (BV/TV), bone trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular spacing (Tb.Sp), bone mineral density (BMD) and strength of distal femurs and increased the levels of procollagen type I N‑terminal propeptide (PINP) and osteocalcin. In contrast, monotherapy with PTH or Scl-Ab showed no differences between treated groups in the assessment of the metaphysis of contralateral femurs by histology, serum, biomechanical tests and micro-CT. These results seem to indicate that Scl-Ab plus PTH has an additive effect on osteoporosis in OVX rats.

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.

Combination of simvastatin, calcium silicate/gypsum, and gelatin and bone regeneration in rabbit calvarial defects

The present study was performed to determine whether simvastatin improves bone regeneration when combined with calcium silicate/gypsum and gelatin (CS-GEL). The surface morphology was determined using field-emission scanning electron microscopy (FSEM). Degradation in vitro was evaluated by monitoring the weight change of the composites soaked in phosphate buffered saline (PBS). Drug release was evaluated using high-performance liquid chromatography (HPLC). Cytotoxicity testing was performed to assess the biocompatibility of composites. Four 5 mm-diameter bone defects were created in rabbit calvaria. Three sites were filled with CS-GEL, 0.5 mg simvastatin-loaded CS-GEL (SIM-0.5) and 1.0 mg simvastatin-loaded CS-GEL (SIM-1.0), respectively, and the fourth was left empty as the control group. Micro-computed tomography (micro-CT) and histological analysis were carried out at 4 and 12 weeks postoperatively. The composites all exhibited three-dimensional structures and showed the residue with nearly 80% after 4 weeks of immersion. Drug release was explosive on the first day and then the release rate remained stable. The composites did not induce any cytotoxicity. The results in vivo demonstrated that the new bone formation and the expressions of BMP-2, OC and type I collagen were improved in the simvastatin-loaded CS-GEL group. It was concluded that the simvastatin-loaded CS-GEL may improve bone regeneration.

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.