Modified and alternative bone cements can improve the induced membrane: Critical size bone defect model in rat femur.

BACKGROUND: As a two-stage surgical procedure, Masquelet's technique has been used to care for critical-size bone defects (CSD). We aimed to determine the effects of modified and altered bone cement with biological or chemical enriching agents on the progression of Masquelet's induced membrane (IM) applied to a rat femur CSD model, and to compare the histopathological, biochemical, and immunohistochemical findings of these cements to enhance IM capacity. METHODS: Thirty-five male rats were included in five groups: plain polymethyl methacrylate (PMMA), estrogen-impregnated PMMA (E+PMMA), bone chip added PMMA (BC+PMMA), hydroxyapatite-coated PMMA (HA) and calcium phosphate cement (CPC). The levels of bone alkaline phosphatase (BALP), osteocalcin (OC), and tumor necrosis factor-alpha (TNF-α) were analyzed in intracardiac blood samples collected at the end of 4 weeks of the right femur CSD intervention. All IMs collected were fixed and prepared for histopathological scoring. The tissue levels of rat-specific Transforming Growth Factor-Beta (TGF-ß), Runt-related Transcription Factor 2 (Runx2), and Vascular Endothelial Growth Factor (VEGF) were analyzed immunohistochemically. RESULTS: Serum levels of BALP and OC were significantly higher in E+PMMA and BC+PMMA groups than those of other groups (P = 0.0061 and 0.0019, respectively). In contrast, TNF-α levels of all groups with alternative bone cement significantly decreased compared to bare PMMA (P = 0.0116). Histopathological scores of E+PMMA, BC+PMMA, and CPC groups were 6.86 ± 1.57, 4.71 ± 0.76, and 6.57 ± 1.51, respectively, which were considerably higher than those of PMMA and HA groups (3.14 ± 0.70 and 1.86 ± 0.69, respectively) (P < 0.0001). Significant increases in TGF-ß and VEGF expressions were observed in E+PMMA and CPC groups (P = 0.0001 and <0.0001, respectively) whereas Runx2 expression significantly increased only in the HA group compared to other groups (P < 0.0001). CONCLUSIONS: The modified PMMA with E and BC, and CPC as an alternative spacer resulted in a well-differentiated IM and increased IM progression by elevating BALP and OC levels in serum and by mediating expressions of TGF-ß and VEGF at the tissue level. Estrogen-supplemented cement spacer has yielded promising findings between modified and alternative bone cement.

Productizing Nano-Bioactive Glass-Based Bilayer Scaffolds: A Graft for Reconstruction of Mandibular and Femoral Bone Defects.

This investigation aimed to construct a bilayer scaffold integrating alginate and gelatin with nanobioactive glass (BG), recognized for their efficacy in tissue regeneration and drug delivery. Scaffolds, namely, alginate/gelatin (AG), alginate-/actonel gelatin (AGD), alginate actenol/gelatin-45S5 BG (4AGD), and alginate-actonel/gelatin-59S BG (5AGD), were assembled using a cost-effective freeze-drying method, followed by detailed structural investigation via powder X-ray diffraction as well as morphological characterization using field emission scanning electron microscopy (FESEM). FESEM revealed a honeycomb-like morphology with distinct pore sizes for nutrient, oxygen, and drug transport. The scaffolds evidently exhibited hemocompatibility, high porosity, good swelling capacity, and biodegradability. In vitro studies demonstrated sustained drug release, particularly for scaffolds containing actonel. In vivo tests showed that the bilayer scaffold promoted new bone formation, surpassing the control group in bone area increase. The interaction of the scaffold with collagen and released ions improved the osteoblastic function and bone volume fraction. The findings suggest that this bilayer scaffold could be beneficial for treating critical-sized bone defects, especially in the mandibular and femoral regions.

Metformin treatment prevents experimental metabolic syndrome-induced femoral bone marrow adiposity in rats. / Tratamiento con metformina previene la adiposidad de la médula ósea femoral inducida por un síndrome metabólico experimental en ratas.

OBJECTIVE.: Motivation for the study. Most research supports a negative association between metabolic syndrome and bone health, although there is an overall lack of consensus. Therefore, there is a need for research in this area to develop a better understanding. Main findings. Metabolic syndrome induced by a fructose-rich diet increases the adipogenic predisposition of bone marrow progenitor cells and femoral medullary adiposity in rats. Furthermore, this can be partially prevented by co-treatment with metformin. Implications. Experimental metabolic syndrome has negative effects on bone tissue and can be prevented by oral treatment with metformin as a normoglycemic drug. To determine the effect of metformin (MET) treatment on adipogenic predisposition of bone marrow progenitor cells (BMPC), bone marrow adiposity and bone biomechanical properties. MATERIALS AND METHODS.: 20 young adult male Wistar rats were sorted into four groups. Each of the groups received the following in drinking water: 100% water (C); 20% fructose (F); metformin 100 mg/kg wt/day (M); or fructose plus metformin (FM). After five weeks the animals were sacrificed. Both humeri were dissected to obtain BMPC, and both femurs were dissected to evaluate medullary adiposity (histomorphometry) and biomechanical properties (3-point bending). BMPC were cultured in vitro in adipogenic medium to evaluate RUNX2, PPAR-γ and RAGE expression by RT-PCR, lipase activity and triglyceride accumulation. RESULTS.: The fructose-rich diet (group F) caused an increase in both triglycerides in vitro, and medullary adiposity in vivo; being partially or totally prevented by co-treatment with metformin (group FM). No differences were found in femoral biomechanical tests in vivo, nor in lipase activity and RUNX2/PPAR-γ ratio in vitro. DRF increased RAGE expression in BMPC, being prevented by co-treatment with MET. CONCLUSIONS.: Metabolic syndrome induced by a fructose-rich diet increases femoral medullary adiposity and, in part, the adipogenic predisposition of BMPC. In turn, this can be totally or partially prevented by oral co-treatment with MET.

OBJETIVO.: Motivación para realizar el estudio. La mayoría de las investigaciones respaldan una asociación negativa entre el síndrome metabólico y la salud ósea, aunque existe una falta de consenso general. Por lo tanto, es necesario realizar investigaciones en esta área que permitan desarrollar un mejor conocimiento. Principales hallazgos. El síndrome metabólico inducido por una dieta rica en fructosa incrementa la predisposición adipogénica de células progenitoras de médula ósea y la adiposidad medular femoral en ratas. Además, esto puede prevenirse parcialmente mediante un co-tratamiento con metformina. Implicancias. El síndrome metabólico experimental posee efectos negativos sobre el tejido óseo, pudiendo ser prevenidos mediante un tratamiento oral de metformina como fármaco normoglucemiante. Determinar el efecto de un tratamiento con metformina (MET) sobre la predisposición adipogénica de células progenitoras de médula ósea (CPMO), adiposidad de la médula ósea y propiedades biomecánicas óseas. MATERIALES Y MÉTODOS.: 20 ratas Wistar machos adultos jóvenes fueron separados en cuatro grupos, recibiendo en agua de bebida: 100% agua (C); 20% de fructosa (F); metformina 100 mg/kg peso/día (M); o fructosa más metformina (FM). Tras cinco semanas se sacrificaron los animales, se diseccionaron ambos húmeros para obtener CPMO, y ambos fémures para evaluar adiposidad medular (histomorfometría) y propiedades biomecánicas (flexión a 3 puntos). Las CPMO se cultivaron in vitro en medio adipogénico para evaluar expresión de RUNX2, PPAR-γ y RAGE por RT-PCR, actividad de lipasa y acumulación de triglicéridos. RESULTADOS.: La dieta rica en fructosa (grupo F) produjo un aumento tanto de triglicéridos in vitro, como de la adiposidad medular in vivo; siendo parcial o totalmente prevenido por un co-tratamiento con metformina (grupo FM). No se observaron diferencias en las pruebas biomecánicas femorales in vivo, ni en actividad de lipasa y relación RUNX2/PPAR-γ in vitro. La DRF aumentó la expresión de RAGE en CPMO, siendo prevenido por co-tratamiento con MET. CONCLUSIONES.: El síndrome metabólico inducido por una dieta rica en fructosa aumenta la adiposidad medular femoral y, en parte, la predisposición adipogénica de las CPMO. A su vez, esto puede ser prevenido total o parcialmente por un co-tratamiento oral con MET.

Bone Regenerative Effect of Injectable Hypoxia Preconditioned Serum-Fibrin (HPS-F) in an Ex Vivo Bone Defect Model.

Biofunctionalized hydrogels are widely used in tissue engineering for bone repair. This study examines the bone regenerative effect of the blood-derived growth factor preparation of Hypoxia Preconditioned Serum (HPS) and its fibrin-hydrogel formulation (HPS-F) on drilled defects in embryonic day 19 chick femurs. Measurements of bone-related growth factors in HPS reveal significant elevations of Osteopontin, Osteoprotegerin, and soluble-RANKL compared with normal serum (NS) but no detection of BMP-2/7 or Osteocalcin. Growth factor releases from HPS-F are measurable for at least 7 days. Culturing drilled femurs organotypically on a liquid/gas interface with HPS media supplementation for 10 days demonstrates a 34.6% increase in bone volume and a 52.02% increase in bone mineral density (BMD) within the defect area, which are significantly higher than NS and a basal-media-control, as determined by microcomputed tomography. HPS-F-injected femur defects implanted on a chorioallantoic membrane (CAM) for 7 days exhibit an increase in bone mass of 123.5% and an increase in BMD of 215.2%, which are significantly higher than normal-serum-fibrin (NS-F) and no treatment. Histology reveals calcification, proteoglycan, and collagen fiber deposition in the defect area of HPS-F-treated femurs. Therefore, HPS-F may offer a promising and accessible therapeutic approach to accelerating bone regeneration by a single injection into the bone defect site.

Immunohistochemical and Morphometric Assessment on the Biological Function and Vascular Endothelial Cells in the Initial Process of Cortical Porosity in Mice With PTH Administration.

To clarify the cellular mechanism of cortical porosity induced by intermittent parathyroid hormone (PTH) administration, we examined the femoral cortical bone of mice that received 40 µg/kg/day (four times a day) human PTH (hPTH) (1-34). The PTH-driven cortical porosity initiated from the metaphyseal region and chronologically expanded toward the diaphysis. Alkaline phosphatase (ALP)-positive osteoblasts in the control mice covered the cortical surface, and endomucin-positive blood vessels were distant from these osteoblasts. In PTH-administered mice, endomucin-reactive blood vessels with TRAP-positive penetrated the ALP-positive osteoblast layer, invading the cortical bone. Statistically, the distance between endomucin-positive blood vessels and the cortical bone surface abated after PTH administration. Transmission electron microscopic observation demonstrated that vascular endothelial cells often pass through the flattened osteoblast layer and accompanied osteoclasts in the deep region of the cortical bone. The cell layers covering mature osteoblasts thickened with PTH administration and exhibited ALP, α-smooth muscle actin (αSMA), vascular cell adhesion molecule-1 (VCAM1), and receptor activator of NF-κB ligand (RANKL). Within these cell layers, osteoclasts were found near endomucin-reactive blood vessels. In PTH-administered femora, osteocytes secreted Dkk1, a Wnt inhibitor that affects angiogenesis, and blood vessels exhibited plasmalemma vesicle-associated protein, an angiogenic molecule. In summary, endomucin-positive blood vessels, when accompanied by osteoclasts in the ALP/αSMA/VCAM1/RANKL-reactive osteoblastic cell layers, invade the cortical bone, potentially due to the action of osteocyte-derived molecules such as DKK1.

Hydrolyzed egg yolk peptide prevented osteoporosis by regulating Wnt/ß-catenin signaling pathway in ovariectomized rats.

Hydrolyzed egg yolk peptide (YPEP) was shown to increase bone mineral density in ovariectomized rats. However, the underlying mechanism of YPEP on osteoporosis has not been explored. Recent studies have shown that Wnt/ß-catenin signaling pathway and gut microbiota may be involved in the regulation of bone metabolism and the progression of osteoporosis. The present study aimed to explore the preventive effect of the YPEP supplementation on osteoporosis in ovariectomized (OVX) rats and to verify whether YPEP can improve osteoporosis by regulating Wnt/ß-catenin signaling pathway and gut microbiota. The experiment included five groups: sham surgery group (SHAM), ovariectomy group (OVX), 17-ß estradiol group (E2: 25 µg /kg/d 17ß-estradiol), OVX with low-dose YPEP group (LYPEP: 10 mg /kg/d YPEP) and OVX with high-dose YPEP group (HYPEP: 40 mg /kg/d YPEP). In this study, all the bone samples used were femurs. Micro-CT analysis revealed improvements in both bone mineral density (BMD) and microstructure by YPEP treatment. The three-point mechanical bending test indicated an enhancement in the biomechanical properties of the YPEP groups. The serum levels of bone alkaline phosphatase (BALP), bone gla protein (BGP), calcium (Ca), and phosphorus (P) were markedly higher in the YPEP groups than in the OVX group. The LYPEP group had markedly lower levels of alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and C-terminal telopeptide of type I collagen (CTX-I) than the OVX group. The YPEP groups had significantly higher protein levels of the Wnt3a, ß-catenin, LRP5, RUNX2 and OPG of the Wnt/ß-catenin signaling pathway compared with the OVX group. Compared to the OVX group, the ratio of OPG/RANKL was markedly higher in the LYPEP group. At the genus level, there was a significantly increase in relative abundance of Lachnospiraceae_NK4A136_group and a decrease in Escherichia_Shigella in YPEP groups, compared with the OVX group. However, in the correlation analysis, there was no correlation between these two bacteria and bone metabolism and microstructure indexes. These findings demonstrate that YPEP has the potential to improve osteoporosis, and the mechanism may be associated with its modulating effect on Wnt/ß-catenin signaling pathway.

Evaluation of the Effects of Whey Protein and Moringa Oleifera Leaves Extract Mixture on Osseointegration in Rabbits.

Background: Osteogenic, antioxidant and anti-inflammatory effects of Whey protein and M. oleifera gel prompted us to evaluate their role alone or in combination on osseointegration in rabbits. Methods: In this study, 24 titanium implants were inserted in the femurs of six rabbits. One implant was placed without treatment, and another one was coated with a mixture of whey protein and M. oleifera gel for each side. The animals were divided into two groups of 2- and 6-week intervals and evaluated using histopathological and immunohistochemical techniques. Results: Histological evaluation revealed a significant difference between the experimental and the control groups after two weeks in osteoblast and osteocyte counts. The experimental group had mature bone development after six weeks of implantation, while the control group had a woven bone. Immunohistochemical results showed that the experimental group, compared to the control group, exhibited early positive expression of osteoblast cells at two weeks after the experiment. Based on histopathological observations, the experimental group showed a tiny area of collagenous fiber in 6th week after the implantation. Conclusion: A mixture of whey protein and M. oleifera could accelerate osseointegration and healing processes.

Synergistic effect of umbilical cord extracellular vesicles and rhBMP-2 to enhance the regeneration of a metaphyseal femoral defect in osteoporotic rats.

BACKGROUND: The aim of this study was to evaluate potential synergistic effects of a single, local application of human umbilical cord MSC-derived sEVs in combination with a low dose of recombinant human rhBMP-2 to promote the regeneration of a metaphyseal femoral defect in an osteoporotic rat model. METHODS: 6 weeks after induction of osteoporosis by bilateral ventral ovariectomy and administration of a special diet, a total of 64 rats underwent a distal femoral metaphyseal osteotomy using a manual Gigli wire saw. Defects were stabilized with an adapted Y-shaped mini-locking plate and were subsequently treated with alginate only, or alginate loaded with hUC-MSC-sEVs (2 × 109), rhBMP-2 (1.5 µg), or a combination of sEVs and rhBMP-2 (n = 16 for each group). 6 weeks post-surgery, femora were evaluated by µCT, descriptive histology, and biomechanical testing. RESULTS: Native radiographs and µCT analysis confirmed superior bony union with callus formation after treatment with hUC-MSC-sEVs in combination with a low dose of rhBMP-2. This finding was further substantiated by histology, showing robust defect consolidation 6 weeks after treatment. Torsion testing of the explanted femora revealed increased stiffness after application of both, rhBMP-2 alone, or in combination with sEVs, whereas torque was only significantly increased after treatment with rhBMP-2 together with sEVs. CONCLUSION: The present study demonstrates that the co-application of hUC-MSC-sEVs can improve the efficacy of rhBMP-2 to promote the regeneration of osteoporotic bone defects.

Plasminogen activator inhibitor-1 is involved in glucocorticoid-induced decreases in angiogenesis during bone repair in mice.

INTRODUCTION: Glucocorticoids delay fracture healing and induce osteoporosis. Angiogenesis plays an important role in bone repair after bone injury. Plasminogen activator inhibitor-1 (PAI-1) is the principal inhibitor of plasminogen activators and an adipocytokine that regulates metabolism. However, the mechanisms by which glucocorticoids delay bone repair remain unclear. MATERIALS AND METHODS: Therefore, we herein investigated the roles of PAI-1 and angiogenesis in glucocorticoid-induced delays in bone repair after femoral bone injury using PAI-1-deficient female mice intraperitoneally administered dexamethasone (Dex). RESULTS: PAI-1 deficiency significantly attenuated Dex-induced decreases in the number of CD31-positive vessels at damaged sites 4 days after femoral bone injury in mice. PAI-1 deficiency also significantly ameliorated Dex-induced decreases in the number of CD31- and endomucin-positive type H vessels and CD31-positive- and endomucin-negative vessels at damaged sites 4 days after femoral bone injury. Moreover, PAI-1 deficiency significantly mitigated Dex-induced decreases in the expression of vascular endothelial growth factor as well as hypoxia inducible factor-1α, transforming growth factor-ß1, and bone morphogenetic protein-2 at damaged sites 4 days after femoral bone injury. CONCLUSION: The present results demonstrate that Dex-reduced angiogenesis at damaged sites during the early bone-repair phase after femoral bone injury partly through PAI-1 in mice.

The "toxic window" of amoxicillin exposure during pregnancy on long bone development in fetal mice.

AIMS: Amoxicillin is a broad-spectrum beta-lactam antibiotic used to treat infectious diseases in pregnant women. Studies have shown that prenatal amoxicillin exposure (PAmE) has developmental toxicity on fetal development. However, the effect of PAmE on long bone development has not been reported. This study aimed to investigate the "toxic window" of PAmE on long bone development and explore its possible mechanism in fetal mice. MATERIALS AND METHODS: Pregnant mice were administered amoxicillin by gavage at different stages (gestational day (GD)10-12 and GD16-18), different doses (150 and 300 mg/kg·d) and different courses (single and multiple courses). Fetal femurs were collected at GD18 and bone development related indicators were detected. KEY FINDINGS: The results showed that PAmE significantly reduced the length of the femur and primary ossification center of fetal mice, and inhibited the development of fetal growth plate. Meanwhile, PAmE inhibited the development of bone marrow mesenchymal stem cells, osteoclasts and endothelial cells in fetal long bone. Further, we found the fetal long bone developmental toxicity induced by PAmE was most significant at late-pregnancy (GD16-18), high dose (300 mg/kg·d) and multiple-course group. Besides, PAmE inhibited the expression of Wnt/ß-catenin signaling pathway in fetal long bone. The ß-catenin mRNA expression was significantly positively correlated with the development indexes of fetal long bone. SIGNIFICANCE: PAmE has toxic effects on long bone development, and there was an obvious "toxic window" of PAmE on the long bone development in fetal mice. The Wnt/ß-catenin signaling pathway may mediate PAmE-induced fetal long bone development inhibition.

Antiosteoporosis effect of bryodulcosigenin on ovariectomy-induced osteoporosis in experimental rats.

PURPOSE: Osteoporosis is a bone disease which commonly occurred in postmenopausal women. Almost 10 percent of world population and approximately 30% of women (postmenopausal) suffer from this disease. Alternative medicine has great success in the treatment of osteoporosis disease. Bryodulcosigenin, a potent phytoconstituent, already displayed the anti-inflammatory and antioxidant effect. In this study, we made effort to analyze the antiosteoporosis effect of bryodulcosigenin against ovariectomy (OVX) induced osteoporosis in rats. METHODS: Swiss albino Wistar rats were grouped into fIve groups and given an oral dose of bryodulcosigenin (10, 20 and 30 mg/kg) for eight weeks. Body weight, uterus, bone mineral density, cytokines, hormones parameters, transforming growth factor (TGF)-ß, insulin-like growth factor (IGF), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), and its ratio were estimated. RESULTS: Bryodulcosigenin significantly (p < 0.001) suppressed the body weight and enhanced the uterine weight and significantly (p < 0.001) increased the bone mineral density in whole femur, caput femoris, distal femur and proximal femur. Bryodulcosigenin significantly (P < 0.001) altered the level of biochemical parameters at dose dependent manner, significantly (P < 0.001) improved the level of estrogen and suppressed the level of follicle stimulating hormone and luteinizing hormone. Bryodulcosigenin significantly (P < 0.001) improved the level of OPG and suppressed the level of RANKL. CONCLUSIONS: Bryodulcosigenin reduced the cytokines level and suppressed the TGF-ß and IGF. We concluded that bryodulcosigenin is an antiosteoporosis medication based on the findings.

Ginsenoside Rc alleviates osteoporosis by the TGF-ß/Smad signaling pathway.

Osteoporosis is a common chronic bone disorder in postmenopausal women. Ginsenosides are primary active components in ginseng and the effects of various ginsenoside variants in osteoporosis treatment have been widely revealed. We planned to explore the impact of ginsenoside Rc on bone resorption in an osteoporosis rat model. We used ovariectomized rats to assess the potential impact of ginsenoside Rc on osteoporosis. µ-CT was implemented for analyzing the microstructure of the distal left femur in rats. H&E staining together with Masson staining were applied for bone histomorphometry evaluation. ELISA kits were implemented to detect serum concentrations of TRACP-5b, OCN, CTX, as well as PINP. Ginsenoside Rc treatment lessened the serum levels of TRACP-5b as well as CTX, while increasing serum levels of OCN, and PINP of OVX rats. Moreover, we found that ginsenoside Rc contributed to the synthesis of type I collagen via increasing Col1a1 and Col1a2 levels in femur tissues of ovariectomized rats. Our findings also revealed that ginsenoside Rc activated the TGF-ß/Smad pathway by increasing TGF-ß as well as phosphorylated Smad2/3 protein levels. Ginsenoside Rc alleviates osteoporosis in rats through promoting the TGF-ß/Smad pathway.

Modulatory interactions of T-2 and deoxynivalenol mycotoxins on murine femoral development and osteological integrity.

In this study, we conducted a systematic assessment of the effectsof deoxynivalenol (DON) and T-2 mycotoxins (T-2) on the developmental processes and structural integrity of murine femurs, considering both the isolated and synergistic effects of these toxins. To this end, we divided 72 male mice into nine groups, each subjected to varying dosages of T-2, DON, or their combinations. Over a four-week experimental period, meticulous monitoring was undertaken regarding the mice's body weight, biochemical markers of bone formation and resorption, and the activity of relevant cells. To comprehensively evaluate alterations in bone structure, we employed biomechanical analysis, micro-computed tomography (micro-CT), and transmission electron microscopy.Our findings unveiled a significant revelation: the mice exhibited a dose-dependent decrease in body weight upon exposure to individual mycotoxins, while the combined use of these toxins manifested an atypical antagonistic effect. Furthermore, we observed variations in the levels of calcium, phosphorus, and vitamin D, as well as adjustments in the activities of osteoblasts and osteoclasts, all intricately linked to the dosage and ratio of the toxins. Alterations in biomechanical properties were also noted to correlate with the dosage and combination of toxins. Analyses via micro-CT and transmission electron microscopy further corroborated the substantial impact of toxin dosage and combinations on both cortical and trabecular bone structures.In summation, our research unequivocally demonstrates the dose- and ratio-dependent detrimental effects of DON and T-2 mycotoxins on the growth and structural integrity of murine femurs. These insights accentuate the importance of a profound understanding of the potential risks these toxins pose to bone health, offering pivotal guidance for future toxicological research and public health preventative strategies.

Favorable osteogenic activity of vericiguat doped in ß-tricalcium phosphate: In vitro and in vivo studies.

Recently, more and more studies have shown that guanylate cyclase, an enzyme that synthesizes cyclic guanosine monophosphate (cGMP), plays an important role in bone metabolism. Vericiguat (VIT), a novel oral soluble guanylate cyclase stimulator, directly generates cyclic guanosine monophosphate and reduce the death incidence from cardio-vascular causes or hospitalization. Recent studies have shown beneficial effects of VIT in animal models of osteoporosis, but very little is currently known about the effects of VIT on bone defects in the osteoporotic states. Therefore, in this study, ß-tricalcium phosphate (ß-TCP) was used as a carrier to explore the effect of local VIT administration on the repair of femoral metaphyseal bone defects in ovariectomized (OVX) rats. When MC3T3-E1 was cultured in the presence of H2H2, VIT, similar to Melatonin (MT), therapy could increase the matrix mineralization and ALP, SOD2, SIRT1, and OPG expression, reduce ROS and Mito SOX production, RANKL expression, Promote the recovery of mitochondrial membrane potential. In the OVX rat model, VIT increases the osteogenic effect of ß-TCP and better results were obtained at a dose of 5 mg. Local use of VIT can inhibit increased OC, BMP2 and RUNX2 expressions in bone tissue, while decreased SOST and TRAP expressions by RT-PCR and immunohistochemistry. Thereby, VIT stimulates bone regeneration and is a promising candidate for promoting bone repair in osteoporosis.

Preparation of Puerarin Long Circulating Liposomes and its Effect on Osteoporosis in Castrated Rats.

Osteoporosis is a disease that causes low bone mass and deterioration of bone microarchitecture. Puerarin is a natural isoflavone compound that has been shown to possess anti-inflammatory, antioxidant and ameliorative effects on osteoporosis with less adverse reactions. However, its fast metabolism and low oral bioavailability limit its application. This study aimed to prepare d-α-tocopherol polyethylene glycol 1000 succinate (TPGS)- modified Puerarin Long Circulating Liposomes (TPGS-Puerarin-liposomes), in order to improve the oral bioavailability of puerarin, before evaluation of its pharmacological activity in vitro and in vivo. We employed film dispersion method to develop TPGS-Puerarin-liposomes before appropriate characterizations. Afterwards, we utilized in vivo imaging, pharmacokinetic analysis and in vitro drug release testing to further evaluate the in vivo and in vitro delivery efficiency. In addition, we established a castrated osteoporosis rat model to observe the changes in femur tissue structure and bone micromorphology via hematoxylin-eosin (HE) staining and Micro Computed Tomography (Micro CT). Besides, levels of oxidative stress and inflammatory indicators, as well as expression of wnt/ß-catenin pathway-related proteins were detected. In terms of physiochemical properties, the respective mean particle size (PS) and zeta potential (ZP) of TPGS-Puerarin-liposomes were 76.63±0.59 nm and -25.54±0.11 mV. The liposomal formulation exhibited encapsulation efficiency (EE) of 95.08±0.25% and drug loading (DL) of 7.84±0.07%, along with excellent storage stability. Compared with free drugs, the TPGS-Puerarin-liposomes demonstrated a sustained release effect and could increase blood concentration of puerarin in rats, thereby significantly improving its bioavailability. Also, in vivo studies have confirmed potential of the liposomes to promote bone tissue targeting and accumulation of puerarin, coupled with significant improvement of the osteoporotic status. Besides, the liposomes could also reduce levels of oxidative stress and inflammatory factors in serum and bone tissue. Additionally, we discovered that TPGS-Puerarin-liposomes increased Wnt, ß-catenin and T-cell factor (TCF) expressions at protein level in the wnt/ß-catenin signaling pathway. This study has demonstrated the potential of TPGS-Puerarin-liposomes for treatment of osteoporosis.

In vivo study of porous NiTi cryotweezers for bone tissue cryotherapy.

This study examined the effects of liquid nitrogen vapor on osteogenesis in the rabbit femur. Cryotweezers made of porous nickel titanium alloy (nitinol or NiTi) obtained by self-propagating high temperature synthesis were used in this experiment. The porous structure of the cryotweezers allows them to hold up to 10 g of liquid nitrogen after being immersed for 2 min, which completely evaporates after 160 s. To study the effects of liquid nitrogen evaporation on osteogenesis, a rabbit femur was perforated. The formed holes were subjected to cryotherapy with varying exposure times. It was found that a 3 s exposure time stimulates osteogenesis, which was manifested in a greater number of osteoblasts in the regenerate compared to the control sample without liquid nitrogen. It was observed that increasing the exposure to 6, 9 or 12 s had a destructive effect, to varying degrees. The most severe damage was exerted by a 12 s exposure, which resulted in the formation of osteonecrosis areas. In the samples exposed to 6 and 9 s of cryotherapy, destruction of the cytoplasm of osteocytes and osteoclasts was observed.

Different methionine to cysteine supplementation ratios altered bone quality of broilers with or without Eimeria challenge assessed by dual energy X-ray absorptiometry and microtomography.

Despite the acknowledged significance of nutrition in bone development, effects of methionine (Met) and cysteine (Cys) on bone quality remain under-researched, particularly during Eimeria challenge. We investigated the effects of different supplemental Met to Cys ratios (MCR) on bone quality of broilers under Eimeria challenge. A total of 720 fourteen-day old Cobb500 broilers were allocated into a 5 × 2 factorial arrangement. Five diets with Met and Cys supplemented at MCR of 100:0, 75:25, 50:50, 25:75, and 0:100 were fed to the birds with or without Eimeria challenge. Body composition was measured by dual energy x-ray absorptiometry, and the femur bone characteristics were assessed by microtomography. Data were analyzed by two-way ANOVA and orthogonal polynomial contrast. The results reaffirmed the detrimental effects of Eimeria challenge on bone quality. On 9 d post inoculation (DPI), significant interaction effects were found for whole body bone mineral content (BMC), lean tissue weight, and body weight (P < 0.05); in the nonchallenged group (NCG), these parameters linearly decreased as MCR decreased (P < 0.05). In the challenged group (CG), body weight and lean tissue weight were unaffected by MCR, and BMC linearly increased as MCR decreased (P < 0.05). For the cortical bone of femoral metaphysis on 6 DPI, bone mineral density (BMD) linearly increased as MCR decreased (P < 0.05). Bone volume to tissue volume ratio (BV/TV) in the CG linearly increased as MCR decreased (P < 0.05). On 9 DPI, BMC and TV linearly increased as MCR decreased (P < 0.05) in the NCG. BMD and BV/TV changed quadratically as MCR decreased (P < 0.05). For the trabecular bone of femoral metaphysis on 9 DPI, BV/TV, and trabecular number linearly increased as MCR decreased (P < 0.05) in the NCG. For the femoral diaphysis, BV, TV, BMC on 6 DPI, and BMD on 9 DPI linearly increased as MCR decreased (P < 0.05). In conclusion, this study showed that both Eimeria challenge and varying supplemental MCR could influence bone quality of broilers.

Cyclosporine a inhibits bone regeneration and induces bone loss in a rat model.

Cyclosporine A (CSA) is an immunosuppressant that has been extensively studied for its side effects on inhibiting osseointegration of titanium implants. However, the impact of CSA on bone healing in postmenopausal osteoporosis remains unknown. Therefore, this study aimed to investigate the effect of CSA on bone repair in an ovariectomized (OVX) rat model through both in vitro and in vivo experiments. We examined the interventions of CSA on osteoblast progenitor cells MC3T3-E1 and assessed their effects on biological function using RT-qPCR, CCK-8 assay, alizarin red staining, and alkaline phosphatase staining. Furthermore, we evaluated the effects of CSA on bone regeneration and bone mass in both OVX rat models and femoral diaphysis bone defect models. The results from the CCK-8 experiment indicated a positive influence of experimental doses of CSA on osteogenic differentiation of MC3T3-E1 cells. ALP expression levels and calcified nodules were also evaluated, suggesting that CSA intervention promoted osteogenic differentiation in MC3T3-E1 cells. Additionally, specific gene expressions including OPN, Runx-2, OC, and Col1a1 were up-regulated after CSA intervention. Biomechanical parameters aligned with histological analysis as well as micro-CT scans confirmed worse bone microstructure and strength following CSA intervention. Our findings preliminarily suggest that whether it is normal or osteoporotic bones, CSA has adverse effects on bone health which are associated with elevated-bone turnover.

Mesenchymal stem cells enhance targeted bone growth from injectable hydrogels with BMP-2 peptides.

Osteoporosis is the most common chronic metabolic bone disease, and the prevalence of osteoporotic fractures is rapidly increasing with the aging population. While bisphosphonates can reduce bone loss and risk of fracture, these drugs are systemic, rely on long-term use, and patient compliance is low. Recombinant human bone morphogenetic protein-2 (BMP-2) is an FDA-approved protein that can offer a more targeted therapeutic than systemic treatments. DWIVA is a peptide sequence corresponding to the wrist epitope of BMP-2, and DWIVA-functionalized hydrogels feature osteoinductive propertiesin vitro and in vivo. This study reports that self-forming DWIVA-functionalized hydrogels injected into the intramedullary canal of rat femurs induce a local increase in trabecular bone in as little as 2 weeks. Increases in bone volume, trabecular thickness, and trabeculae count from DWIVA-laden hydrogels persist for at least 4 weeks, and the inclusion of mesenchymal stem cells (MSCs) significantly enhances the development of mineralized bone. Histological analysis of decalcified femurs also shows that hydrogel injections containing DWIVA peptide and MSCs stimulate unmineralized bone tissue formation and induce an increased count of osteoblasts and osteoclasts at the injection site after 4 weeks. Overall, the MSC-laden DWIVA peptide-functionalized hydrogels presented rapidly induce targeted bone formation and have the potential to form nascent bone within bones in jeopardy of an osteoporotic fracture such as the femur.

Tacrolimus, FK506, promotes bone formation in bone defect mouse model.

OBJECTIVES: Some studies have reported that tacrolimus (FK506), an immunosuppressant, may have positive effects on bone formation. However, the precise effects of FK506 on bone repair or osteoblasts remain inadequately elucidated, and limited research has explored the outcomes of its use in an in vivo mouse model. This study aims to examine the effects of FK506 on bone repair and osteoblast functions using bone defect and BMP-2-induced ectopic ossification mouse models, as well as cultured primary mouse osteoblasts treated with FK506. METHODS: We established mouse models of femur bone defect and BMP-2-induced ectopic ossification to evaluate the effect of FK506 on new bone formation, respectively. Additionally, primary mouse osteoblasts were cultured with FK506 and examined for gene expressions related to osteoblast differentiation. RESULTS: While FK506 promoted the repair of bone defect areas in the femur of the bone defect mouse model, it also led to widespread abnormal bone formation outside the intended area. Additionally, following the implantation of a collagen sponge containing BMP-2 into mouse muscle tissue, FK506 was found to promote ectopic ossification and enhance BMP-2-induced osteoblast differentiation in vitro. Our findings also revealed that FK506 increased the number of immature osteoblasts in the absence of BMP-2 without affecting osteoblast differentiation. Furthermore, direct effects were observed, reducing the ability of osteoblasts to support osteoclastogenesis. CONCLUSIONS: These results indicate that FK506 increases new bone formation during bone repair and influences the proliferation of immature osteoblasts, as well as osteoblast-supported osteoclastogenesis.