Tartrate-resistant Acid Phosphatase Staining Research Articles

Reduced graphene oxide loaded with tetrahedral framework nucleic acids for combating orthodontically induced root resorption.

Root resorption occurs outside the root or within the root canal. Regardless of its region, root resorption is irreversible and in severe cases, may even cause tooth loss. Clinically, the external surface root resorption is usually a side effect of orthodontic tooth movement. However, it is frustrating to note that there are almost no effective treatment strategies for orthodontically induced root resorption (OIRR) due to the complexity and ambiguity of etiology. In the current study, we successfully fabricated a delivery complex, reduced graphene oxide nanosheet loading with tetrahedral framework nucleic acids (tFNAs-rGO) through self-assembly. No significant cytotoxicity or organ-toxicity of the tFNAs-rGO complex was observed in cell counting kit-8 assay (CCK-8) and hematoxylin-eosin (HE) staining. Histological staining such as tartrate-resistant acid phosphatase (TRAP) staining and Micro-CT three-dimensional reconstruction were employed to explore the dynamic changes of root and peri-root tissues in OIRR mice. In vitro, we developed an induction microenvironment to testify the effects of the tFNAs-rGO delivery complex on periodontal ligament cells (PDLCs) and macrophages by quantitative RT-PCR, western blot, and immunofluorescence staining. The data showed the reduced the region of root resorption and downregulated osteoclastic activity in OIRR by the tFNAs-rGO complex treatment. Furthermore, our study demonstrated that the tFNAs-rGO delivery complex enhanced osteogenic differentiation of PDLCs and facilitated M2-phenotype polarization of macrophages to ameliorate OIRR. Collectively, the insight into the nanoscale dual-functional tFNAs-rGO delivery complex regulating the cell populations of PDLCs and macrophages in the root resorption remodeling proposes a promising therapeutic strategy for orthodontically induced root resorption.

Allograft to bone-tunnel integration in a canine anterior cruciate ligament reconstruction model: a comparison study of allograft preparation methods

The procedure of anterior cruciate ligament (ACL) allograft preparation can be divided into fresh-frozen method (FF-allograft) or freeze-dried method (FD-allograft). This study aims to biomechanically and histologically compare the graft to bone tunnel integration between the two allografts. In-vitro results indicated that FF-allograft and FD-allograft showed excellent biocompatibility and biomechanics, while FD-allograft showed a denser collagen fiber arrangement than FF-allograft and autograft. Then, in-vivo preformation of the FF-allograft, FD-allograft, and autograft on bone tunnel integration was evaluated via a canine ACL reconstruction model. In-vivo results indicated that no signs of infection or osteoarthritis were shown in the femur-graft-tibia complexes, but more vascularity and synovitis formed around the implanted FF-allograft. Micro-computed tomography showed that peri-graft bone in the FF-allograft group was significantly increased and remodeled compared with the FD-allograft group; Histologically, the FF-allograft group exhibited similar graft-bone tunnel healing to the FD-allograft group. Tartrate-resistant acid phosphatase (TRAP) staining showed significantly more osteoclasts presented in the FD-allograft group compared to the FF-allograft group. Meanwhile, a significantly higher failure load was shown in the FF-allograft group when compared with the FD-allograft group (P < 0.05). In conclusion, the FF-allograft integrated more firmly into the bone tunnel than the FD-allograft when used in ACL reconstruction.

The Acetylated 2,3,5,4′-Tetrahydroxystilbene-2-O-β-d-Glucoside Improved Pharmacokinetics and Enhanced Anti-Osteoporosis Effects

Background: Osteoporosis has emerged as a significant global public health concern, predominantly affecting postmenopausal women. Its pathogenesis is intricate and the disease course is protracted, imposing substantial medical burden on both society and individuals. Objective: To investigate the effects of 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside (TSG) and acetylated-TSG (Ac-TSG) on osteoblast viability, in vivo pharmacokinetics in rats and anti-osteoporotic effects in ovariectomized rat model. Methods: Ac-TSG was obtained by acetylation of TSG, and the purity and structure of Ac-TSG were determined by HPLC and 1H NMR. The effects of TSG and Ac-TSG on MC3T3-E1 cell viability, pharmacokinetics in rats, blood biochemical indexes of OVX model rats were detected. Hematoxylin–eosin (HE) staining was used to observe bone tissue morphology, tartrate-resistant acid phosphatase (TRAP) staining was used to observe osteoclast morphology, micro-CT was used to perform three-dimensional reconstruction of femur, and femur parameters were analyzed. Results: The structure of the compound is Ac-TSG and the purity is more than 98%. Both TSG and Ac-TSG could reduce the damage of oxidative stress to MC3T3-E1 cells and effectively improve the levels of Ca, P, ALP and BGP in serum of OVX rats. Compared with TSG, Ac-TSG has a longer action time in vivo and can improve the femoral structure, the number of trabecular bone and the number of osteoclasts in rats. Conclusion: Ac-TSG conferred protection to MC3T3-E1 cells against oxidative stress-induced damage and enhanced their bioavailability. Simultaneously, Ac-TSG ameliorated abnormal bone metabolism and mitigated bone microstructural changes in OVX rats, exhibiting a protective effect against osteoporosis.

Lactiplantibacillus plantarum P101 Ameliorates TiO2 NP-Induced Bone Injury in Young Rats by Remodeling the Gut Microbiota and Inhibiting the Production of Pro-Inflammatory Cytokines.

To evaluate the therapeutic effect of oral administration of Lactiplantibacillus plantarum P101 (P101) on skeletal injury in young rats exposed to titanium dioxide nanoparticles (TiO2 NPs), and explore the potential mechanism. Four-week-old male rats were orally administration to TiO2 NPs and supplemented with P101 2hours later for 4weeks. The growth and development, food intake, bone metabolism and serum inflammatory markers of the rats were evaluated. Their tibias were observed and evaluated using microcomputed tomography (micro-CT), tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry (IHC) and real-time quantitative PCR (RT-qPCR). We observed the tibia growth plate using safranin and fast green staining. 16S rDNA sequence analysis of fecal samples was performed to observe changes in the gut microbiota. Our results showed that TiO2 NPs can lead to bone growth inhibition and osteoporosis, induce intestinal flora imbalance, and induce inflammation in young rats. Further mechanistic studies suggested that TiO2 NPs disrupts intestinal flora and increases serum IL-1β levels, which increased the expression of RANKL in bone, thereby enhancing osteoclast differentiation and function, leading to bone loss. Through a P101 supplementation experiment, we found that P101 ameliorated the inflammation and osteoporosis on bone caused by TiO2 NPs. This study showed that the mechanism by which P101 alleviates bone damage caused by TiO2 NPs may be through restoring intestinal microbial homeostasis and inhibiting inflammatory response.

The Biphasic Activity of Auricularia Auricula-Judae Extract on Bone Homeostasis Through Inhibition of Osteoclastogenesis and Modulation of Osteogenic Activity.

Osteoporosis arises from the disturbance of bone homeostasis, a process regulated by osteoblasts and osteoclasts. The treatment and prevention of bone metabolic disorders resulting from an imbalance in bone homeostasis require the use of agents that effectively promote both bone formation and anti-resorptive effects. Therefore, an investigation was carried out to determine the potential of the edible mushroom Auricularia auricula-judae in modulating bone remodeling by inhibiting RANKL-induced osteoclastogenesis and enhancing BMP-2-stimulated osteoblast differentiation. Moreover, this study assessed the mode of action of the Auricularia auricula-judae extracts. The staining of tartrate-resistant acid phosphatase (TRAP), a marker for osteoclast activity, demonstrated that Auricularia auricula-judae water extract (AAJWE) inhibited the formation of multinucleated osteoclasts while exhibiting no cytotoxic effects. The study demonstrated that AAJWE reduced RANKL-induced osteoclast differentiation by inhibiting c-Fos/NFATc1 through the inhibition of ERK and JNK phosphorylation during the RANKL-induced osteoclast differentiation. Moreover, AAJWE exhibited a dose-dependent induction of ALP expression in the presence of BMP-2 during osteoblast differentiation. The AAJWE strengthened BMP-2-induced osteogenesis through the activation of Runx2 and Smad phosphorylation. Therefore, AAJWE emerges as a promising candidate for both prevention and therapy owing to its biphasic effect, which aids in the preservation of bone homeostasis.

Tectochrysin Alleviates Periodontitis by Modulating M2/M1 Macrophage Ratio and Oxidative Stress Via Nuclear Factor Kappa B/Heme Oxygenase-1/Nuclear Factor Erythroid 2-Related Factor 2 Pathway

ABSTRACT Background Tectochrysin suppresses several diseases. In this study, we aimed to explore the effects of tectochrysin ona rat model of periodontitis PDS). Methods Male Sprague-Dawley (SD) rats were subjected to ligature to induce periodontitis. Bone parameters were analyzed using micro-computed tomography and periodontal tissues were evaluated using Masson’s, hematoxylin and eosin, and tartrate-resistant acid phosphatase staining. The expression of HO-1, Nrf2, CD206, Arg-1, and iNOS was evaluated using immunohistochemistry. Malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD) levels and IL-1β, IL-6, and tumor necrosis factor (TNF)-α,and NF-κB and Nrf2/HO-1 were analyzed. Results Tectochrysin reduced alveolar bone loss, promoted new bone formation, and inhibited osteoclast formation in periodontitis rats. It decreased the number of inflammatory cells and the levels of IL-1β, IL-6, and TNF-α, indicating a reduction in inflammation. Tectochrysin restored the Arg-1/iNOS ratio, indicating M2 macrophage polarization, and inhibited the NF-kB pathway. Tectochrysin restored GSH and SOD levels, inhibited MDA content, and activated the HO-1/Nrf2 pathway. Conclusion Tectochrysin alleviates PDS in rats by modulating the M2/M1 macrophage ratio via the NF-kB pathway and suppressing oxidative stress via the HO-1/Nrf2 pathway.

Amentoflavone maintaining extracellular matrix homeostasis and inhibiting subchondral bone loss in osteoarthritis by inhibiting ERK, JNK and NF-κB signaling pathways

Amentoflavone (AF), a plant biflavone isolated from Selaginella sinensis ethanol extract, is characterized by anti-inflammatory and anti-oxidant properties. According to previous studies, inflammation and oxidative stress are closely related to the pathophysiology of osteoarthritis (OA). However, the effects and mechanisms of AF on OA have not been elucidated.To investigate the inhibitory effects and its molecular mechanism of AF on extracellular matrix (ECM) degradation stimulated by IL-1β as well as subchondral bone loss induced by RANKL in mice chondrocytes. Quantitative PCR was used to detect the mRNA expression of genes related to inflammation, ECM, and osteoclast differentiation. Protein expression level of iNOS, COX-2, MMP13, ADAMTS5, COL2A1, SOX9, NFATc1, c-fos, JNK, ERK, P65, IκBα was measured by western blotting. The levels of TNF-α and IL-6 in the supernatants were measured by ELISA. The amount of ECM in chondrocytes was measured using toluidine blue staining. The levels of Aggrecan and Col2a1 in chondrocytes were measured using immunofluorescence. Tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining and immunofluorescence were used to detect the effect of AF on osteoclast differentiation and bone resorption. The effect of AF on destabilization of the medial meniscus (DMM)-induced OA mice can be detected in hematoxylin–eosin (H&E) staining, Safranin O green staining and immunohistochemistry.AF might drastically attenuated IL-1β-stimulated inflammation and reduction of ECM formation by blocking ERK and NF-κB signaling pathways in chondrocytes. Meanwhile, AF suppressed the formation of osteoclasts and the resorption of bone function induced by RANKL. In vivo, AF played a protective role by stabilizing cartilage ECM and inhibiting subchondral bone loss in destabilization of the medial meniscus (DMM)-induced OA mice, further proving its protective effect in the development of OA. Our study show that AF alleviated OA by suppressing ERK, JNK and NF-κB signaling pathways in OA models in vitro and DMM-induced OA mice, suggesting that AF might be a potential therapeutic agent in the treatment of OA.

TGF-β signaling in the cranial neural crest affects late-stage mandibular bone resorption and length.

Malocclusions are common craniofacial malformations that cause quality of life and health problems if left untreated. Unfortunately, the current treatment for severe skeletal malocclusion is invasive surgery. Developing improved therapeutic options requires a deeper understanding of the cellular mechanisms responsible for determining jaw bone length. We have recently shown that neural crest mesenchyme (NCM) can alter jaw length by controlling the recruitment and function of mesoderm-derived osteoclasts. Transforming growth factor beta (TGF-β) signaling is critical to craniofacial development by directing bone resorption and formation, and heterozygous mutations in the TGF-β type I receptor (TGFBR1) are associated with micrognathia in humans. To identify the role of TGF-β signaling in NCM in controlling osteoclasts during mandibular development, the mandibles of mouse embryos deficient in the gene encoding Tgfbr1, specifically in NCM, were analyzed. Our laboratory and others have demonstrated that Tgfbr1 fl/fl ;Wnt1-Cre mice display significantly shorter mandibles with no condylar, coronoid, or angular processes. We hypothesize that TGF-β signaling in NCM can also direct late bone remodeling and further regulate late embryonic jaw bone length. Interestingly, analysis of mandibular bone based on micro-computed tomography and Masson's trichrome revealed no significant difference in bone quality between the Tgfbr1 fl/fl ;Wnt1-Cre mice and controls, as measured by the bone perimeter/bone area, trabecular rod-like diameter, number and separation, and gene expression of collagen type 1 alpha 1 (Col1α1) and matrix metalloproteinase 13 (Mmp13). Although there was not a difference in localization of bone resorption within the mandible indicated by tartrate-resistant acid phosphatase (TRAP) staining, Tgfbr1 fl/fl ;Wnt1-Cre mice had approximately three-fold less osteoclast number and perimeter than controls. Gene expression of receptor activator of nuclear factor kappa-β (Rank) and Mmp9, markers of osteoclasts and their activity, also showed a three-fold decrease in Tgfbr1 fl/fl ;Wnt1-Cre mandibles. Evaluation of osteoblast-to-osteoclast signaling revealed no significant difference between Tgfbr1 fl/fl ;Wnt1-Cre mandibles and controls, leaving the specific mechanism unresolved. Finally, pharmacological inhibition of Tgfbr1 signaling during the initiation of bone mineralization and resorption significantly shortened jaw length in embryos. We conclude that TGF-β signaling in NCM decreases mesoderm-derived osteoclast number, that TGF-β signaling in NCM impacts jaw length late in development, and that this osteoblast-to-osteoclast communication may be occurring through an undescribed mechanism.

Integrated analysis of single-cell RNA-seq and bulk RNA-seq revealed key genes for bone metastasis and chemoresistance in prostate cancer.

Prostate cancer (PCa) is a serious malignancy. The main causes of PCa aggravation and death are unexplained resistance to chemotherapy and bone metastases. This study aimed to investigate the molecular mechanisms associated with the dynamic processes of progression, bone metastasis, and chemoresistance in PCa. Through comprehensive analysis of single-cell RNA sequencing (scRNA-seq) data, Gene Expression Omnibus (GEO) tumor progression and metastasis-related genes were identified. These genes were subjected to lasso regression modeling using the Cancer Genome Atlas (TCGA) database. Tartrate-resistant acid phosphatase (TRAP) staining and real-time quantitative PCR (RT-qPCR) were used to evaluate osteoclast differentiation. CellMiner was used to confirm the effect of LDHA on chemoresistance. Finally, the relationship between LDHA and chemoresistance was verified using doxorubicin-resistant PCa cell lines. 7928 genes were identified as genes related to tumor progression and metastasis. Of these, 7 genes were found to be associated with PCa prognosis. The scRNA-seq and TCGA data showed that the expression of LDHA was higher in tumors and associated with poor prognosis of PCa. In addition, upregulation of LDHA in PCa cells induces osteoclast differentiation. Additionally, high LDHA expression was associated with resistance to Epirubicin, Elliptinium acetate, and doxorubicin. Cellular experiments demonstrated that LDHA knockdown inhibited doxorubicin resistance in PCa cells. LDHA may play a potential contributory role in PCa initiation and development, bone metastasis, and chemoresistance. LDHA is a key target for the treatment of PCa.

Therapeutic effect of bloodletting on bone deterioration induced by hypobaric hypoxia in young rats

ObjectivesHigh-altitude regions, comprising hypoxic conditions, are associated with different altitude-induced pathologies, including a reduction in bone density. Elucidating the mechanisms underlying bone degradation in such environments and developing targeted interventions and therapeutics is important. Bloodletting therapy has promising clinical applications, but its effects on the skeletal system and bone homeostasis are not well understood. The aim of this study was to investigate the effects of a hypobaric hypoxia environment on specific femoral morphological and structural properties, including bone volume, cortical thickness, and trabecular microarchitecture, in juvenile Sprague–Dawley (SD) rats, and to explore the potential modulating effects of a bloodletting intervention on these parameters. MethodsMale SD rats, 6 weeks of age, were subjected to a simulated hypobaric hypoxia environment, replicating a 5000-m altitude, for 12 weeks. For the bloodletting intervention group, rats were subjected to a weekly 500 μL tail vein blood withdrawal. Micro-CT technology, hematoxylin and eosin staining, and tartrate-resistant acid phosphatase staining were employed to comprehensively assess the femoral microstructure, tissue architecture, and cellular morphology. Additionally, immunofluorescence analysis was conducted to quantify the expression of key proteins, and transcriptome analysis was performed to identify differentially expressed genes. ResultsExposure of rats to hypobaric hypoxia led to a significant reduction in bone mineral content, trabecular bone number, and cortical bone thickness, suggesting a deterioration of bone microstructure. Additionally, the hypoxic environment upregulated the expression of RANKL and HIF-1α, while downregulating RUNX2. Notably, although bloodletting intervention did not significantly reverse these bone structural changes, transcriptome analysis revealed its regulatory influence on the expression of key genes, particularly Mmp2, Fosl2, and URS0000B2A65A, which are implicated in pathways governing the hypoxic response, osteoclast differentiation, and PI3K–Akt signaling. ConclusionThis study highlights the detrimental effect of hypobaric hypoxia on the bone microstructure of juvenile rats and underscores the therapeutic potential of bloodletting to ameliorate this condition. Additionally, our study on the regulatory mechanisms mediating bloodletting's effects on gene expression offers fresh perspectives on bone alterations. It suggests promising avenues for the development of novel preventative measures and targeted therapies to address the challenges posed by related bone disorders.

Exogenous Angiotensin-(1-7) Provides Protection Against Inflammatory Bone Resorption and Osteoclastogenesis by Inhibition of TNF-α Expression in Macrophages.

Renin-angiotensin-aldosterone system plays a crucial role in the regulation of blood pressure and fluid homeostasis. It is reported to be involved in mediating osteoclastogenesis and bone loss in diseases of inflammatory bone resorption such as osteoporosis. Angiotensin-(1-7), a product of Angiotensin I and II (Ang I, II), is cleaved by Angiotensin-converting enzyme 2 and then binds to Mas receptor to counteract inflammatory effects produced by Ang II. However, the mechanism by which Ang-(1-7) reduces bone resorption remains unclear. Therefore, we aim to elucidate the effects of Ang-(1-7) on lipopolysaccharide (LPS)-induced osteoclastogenesis. In vivo, mice were supracalvarial injected with Ang-(1-7) or LPS ± Ang-(1-7) subcutaneously. Bone resorption and osteoclast formation were compared using micro-computed tomography, tartrate-resistant acid phosphatase (TRAP) stain, and real-time PCR. We found that Ang-(1-7) attenuated tumor necrosis factor (TNF)-α, TRAP, and Cathepsin K expression from calvaria and decreased osteoclast number along with bone resorption at the suture mesenchyme. In vitro, RANKL/TNF-α ± Ang-(1-7) was added to cultures of bone marrow-derived macrophages (BMMs) and osteoclast formation was measured via TRAP staining. The effect of Ang-(1-7) on LPS-induced osteoblasts RANKL expression and peritoneal macrophages TNF-α expression was also investigated. The effect of Ang-(1-7) on the MAPK and NF-κB pathway was studied by Western blotting. As a result, Ang-(1-7) reduced LPS-stimulated macrophages TNF-α expression and inhibited the MAPK and NF-κB pathway activation. However, Ang-(1-7) did not affect osteoclastogenesis induced by RANKL/TNF-α nor reduce osteoblasts RANKL expression in vitro. In conclusion, Ang-(1-7) alleviated LPS-induced osteoclastogenesis and bone resorption in vivo via inhibiting TNF-α expression in macrophages.

Promotion of mandibular distraction osteogenesis by parathyroid hormone via macrophage polarization induced through iNOS downregulation

ObjectiveTo investigate whether Parathyroid hormone (PTH) can promote mandibular distraction osteogenesis by regulating macrophage polarization and the underlying mechanisms of this phenomenon. MethodsForty-eight Rabbits were used to establish the mandibular distraction osteogenesis experimental model, randomly divided into 2 groups. Intermittent post-operative injections of 20 μg/kg PTH and normal saline were administered to the experimental and control groups, respectively. Regenerated new bone was examined using HE staining, osteoclast numbers were determined through tartrate-resistant acid phosphatase (TRAP) staining, and macrophage polarization markers arginase 1 (Arg1) and inducible nitric oxide synthase (iNOS) expressions were elucidated using immunohistochemistry (IHC), the mRNA expression of CD206, CD11C, Arg1 and iNOS were detected using qPCR. ResultsThe bone trabeculae in the experimental group were thicker, with a more homogeneous structure and more new osteoid than in the control group. In the area of distraction osteogenesis, the osteoclast count in the experimental group was higher than in the control group (P < 0.05). IHC results indicated differential expressions of Arg1 and iNOS in the experimental group compared to the control group (P < 0.05). Relative mRNA expressions of CD11c and iNOS were lower in the experimental group than in the control group (P < 0.05), whereas the expressions of CD206 and Arg1 mRNA were higher in the experimental group compared to the control group (P < 0.05). ConclusionIntermittent PTH injections increased macrophage quantity in the mandible generated by distraction osteogenesis, downregulated iNOS, upregulated Arg1, and promoted macrophage polarization from M1 to M2 phenotype, thereby promoting mandibular distraction osteogenesis.

Exacerbating orthodontic tooth movement in mice with salt-sensitive hypertension

Background/purposeOrthodontic tooth movement (OTM) is a critical aspect of dental treatment that requires the precise control of bone remodeling processes. Hypertension (HTN) can affect the effectiveness of OTM. Salt-sensitive hypertension (SSHTN) is of particular concern due to its detrimental effects on bone health, potentially altering orthodontic outcomes. This study aimed to investigate the effects of SSHTN on OTM using a mouse model. Materials and methodsMale mice were divided into a normal and an SSHTN group. The SSHTN model was generated by administering N(ω)-nitro-l-arginine methyl ester (l-NAME) followed by a high-salt diet. The OTM was performed using a nickel-titanium (Ni-Ti) closed-coil spring, and the tooth movement was measured after 12 days. Silicone imprinting was used to estimate the OTM distance. Osteoclast activity was assessed using tartrate-resistant acid phosphatase (TRAP) staining of decalcified maxillary sections. ResultsSSHTN mice exhibited significantly increased tooth movement compared to normal mice. This enhanced movement was associated with more osteoclasts in the SSHTN group than in the control group. These findings suggest that SSHTN increases OTM levels by promoting bone resorption. ConclusionSSHTN significantly affected OTM by enhancing osteoclast activity and increasing tooth movement. These results underscore the importance of considering hypertensive conditions in orthodontic treatment planning as they may require adjustments in force application to prevent potential adverse effects.

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

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

Unraveling devitalization: its impact on immune response and ectopic bone remodeling from autologous and allogeneic callus mimics.

Endochondral bone regeneration is a promising approach in regenerative medicine. Callus mimics (CMs) are engineered and remodeled into bone tissue upon implantation. The long-term objective is to fabricate a sustainable off-the-shelf treatment option for patients. Devitalization was introduced to facilitate storage and using allogeneic (donor) cells would further propel the off-the-shelf approach. However, allogeneic CMs for bone regeneration pose a potential antigenicity concern. Here, we explored the impact of devitalization on antigenicity and osteoinductive bone formation when implanting syngeneic or allogeneic CM in a vital or devitalized state. For this, we implanted chondrogenically differentiated rat-derived mesenchymal stromal cells using an allogeneic immunocompetent ectopic rat model. Vital syngeneic CMs demonstrated the highest bone formation, and vital allogeneic CMs showed the lowest bone formation, while both devitalized CMs showed comparable intermediate levels of bone formation. Preceding bone formation, the level of tartrate-resistant acid phosphatase staining at 7 and 14 days was proportional to the level of eventual bone formation. No differences were observed for local innate immune responses at any time point before or after bone formation. In contrast, allogeneic CMs elicit a mild adaptive immune response, which still permits bone formation in an immunocompetent environment, albeit at a reduced rate compared to the autologous living counterpart. Overall, devitalization delays bone formation when autologous CMs are implanted, whereas it accelerates bone formation in allogeneic CMs, highlighting the potential of this approach for achieving off-the-shelf treatment.

Epimedin A inhibits the PI3K/AKT/NF-κB signalling axis and osteoclast differentiation by negatively regulating TRAF6 expression

BackgroundEpimedin A (EA) has been shown to suppress extensive osteoclastogenesis and bone resorption, but the effects of EA remain incompletely understood. The aim of our study was to investigate the effects of EA on osteoclastogenesis and bone resorption to explore the corresponding signalling pathways.MethodsRats were randomly assigned to the sham operation or ovariectomy group, and alendronate was used for the positive control group. The therapeutic effect of EA on osteoporosis was systematically analysed by measuring bone mineral density and bone biomechanical properties. In vitro, RAW264.7 cells were treated with receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) to induce osteoclast differentiation. Cell viability assays, tartrate-resistant acid phosphatase (TRAP) staining, and immunofluorescence were used to elucidate the effects of EA on osteoclastogenesis. In addition, the expression of bone differentiation-related proteins or genes was evaluated using Western blot analysis or quantitative polymerase chain reaction (PCR), respectively.ResultsAfter 3 months of oral EA intervention, ovariectomized rats exhibited increased bone density, relative bone volume, trabecular thickness, and trabecular number, as well as reduced trabecular separation. EA dose-dependently normalized bone density and trabecular microarchitecture in the ovariectomized rats. Additionally, EA inhibited the expression of TRAP and NFATc1 in the ovariectomized rats. Moreover, the in vitro results indicated that EA inhibits osteoclast differentiation by suppressing the TRAF6/PI3K/AKT/NF-κB pathway. Further studies revealed that the effect on osteoclast differentiation, which was originally inhibited by EA, was reversed when the TRAF6 gene was overexpressed.ConclusionsThe findings indicated that EA can negatively regulate osteoclastogenesis by inhibiting the TRAF6/PI3K/AKT/NF-κB axis and that ameliorating ovariectomy-induced osteoporosis in rats with EA may be a promising potential therapeutic strategy for the treatment of osteoporosis.

Suppressing anti-citrullinated protein antibody-induced osteoclastogenesis in rheumatoid arthritis using anti-CD64 and PAD-2 inhibitors.

To evaluate the role of Fcγ receptors (FcγR) and peptidyl arginine deiminase (PAD) in anti-citrullinated protein antibody (ACPA)-induced fibroblast-like synoviocytes (FLSs)-mediated osteoclastogenesis in patients with rheumatoid arthritis (RA). FLSs and peripheral blood mononuclear cells were collected from patients with RA. We stimulated RA-FLS with ACPA (100 ng/ml) with and without anti-cluster of differentiation (CD)32a/CD64 (FcγRIIA/FcγRI) antibody and PAD-2/4 inhibitors. Flow cytometry and enzyme-linked immunosorbent assay were also performed. CD14+ monocytes were cultured with receptor activator of nuclear factor kappa beta (RANKL) and macrophage colony-stimulating factor, and ACPA-stimulated RA-FLSs were added. These cells were cultured for 14 days, and osteoclastogenesis was quantified using tartrate-resistant acid phosphatase (TRAP) staining. ACPA increased RANKL+ and tumour necrotic factor-alpha (TNF-α+) FLS, which decreased dose-dependently by adding 5 and 10 ug/mL anti-CD64 antibody rather than anti-CD32a antibody. In PAD inhibitor experiments, the proportion of RANKL+ and TNF-α+ FLS decreased in 50 μM condition containing PAD-2 inhibitor rather than PAD-4 inhibitor. The co-culture of ACPA-stimulated RA-FLSs and osteoclast precursors increased the TRAP+ multinucleated osteoclast count, which was decreased by anti-CD64 antibody and PAD2 inhibitor. The present study showed that ACPA increased RANKL and pro-inflammatory cytokine expression in RA-FLSs, and ACPA-activated RA-FLSs could augment osteoclastogenesis. These processes were inhibited by treatment with anti-CD64 antibody and PAD-2 inhibitors. These results show that CD64 and PAD-2-induced pathways may be involved in ACPA-induced FLS activation and osteoclastogenesis in patients with RA. Therefore, regulating the CD64 and PAD-2 pathways may improve RA treatment.

Ganoderic Acid A prevents bone loss in lipopolysaccharide-treated male rats by reducing oxidative stress and inflammatory

Ganoderic Acid A (GAA) has demonstrated beneficial effects in anti-inflammatory and anti-oxidative stress studies. However, it remains unknown whether GAA exerts positive impacts on bone loss induced by lipopolysaccharide (LPS). This study aims to investigate the influence of GAA on bone loss in LPS-treated rats. The study assesses changes in the viability and osteogenic potential of MC3T3-E1 cells, as well as osteoclast differentiation in RAW264.7 cells in the presence of LPS using CCK-8, ALP staining, AR staining, and Tartrate-resistant acid phosphatase (TRAP) staining. In vitro experiments indicate that LPS-induced inhibition of osteoclasts (OC) and Superoxide Dismutase 2 (SOD2) correlates with heightened levels of inflammation and oxidative stress. Furthermore, GAA has displayed the ability to alleviate oxidative stress and inflammation, enhance osteogenic differentiation, and suppress osteoclast differentiation. Animal experiment also proves that GAA notably upregulates SOD2 expression and downregulates TNF-α expression, leading to the restoration of impaired bone metabolism, improved bone strength, and increased bone mineral density. The collective experimental findings strongly suggest that GAA can enhance osteogenic activity in the presence of LPS by reducing inflammation and oxidative stress, hindering osteoclast differentiation, and mitigating bone loss in LPS-treated rat models.

Effect of low-intensity pulsed ultrasound on the mineralization of force-treated cementoblasts and orthodontically induced inflammatory root resorption via the Lamin A/C-Yes associated protein axis.

Orthodontic treatment commonly results in orthodontically induced inflammatory root resorption (OIIRR). This condition arises from excessive orthodontic force, which triggerslocal inflammatory responses and impedes cementoblasts' mineralization capacity. Low-intensity pulsed ultrasound (LIPUS) shows potential in reducing OIIRR. However, the precise mechanisms through which LIPUS reduces OIIRR remain unclear. This study aimed to explore the effects and mechanisms of LIPUS on the mineralization of force-treated cementoblasts and its impact on OIIRR. We established a rat OIIRR model and locally administered LIPUS stimulation for 7 and 14 days. We analyzed root resorption volume, osteoclast differentiation, and the expression of osteocalcin and yes-associated protein 1 (YAP1) using micro-computed tomography (micro-CT), hematoxylin and eosin, tartrate-resistant acid phosphatase, immunofluorescence and immunohistochemistry staining. Invitro, we applied compressive force and LIPUS to the immortalized mouse cementoblasts (OCCM30). We assessed mineralization using alkaline phosphatase (ALP) staining, alizarin red staining, real-time quantitative polymerase chain reaction, Western blotting and immunofluorescence staining. In rats, LIPUS reduced OIIRR, as evidenced by micro-CT analysis and histological staining. Invitro, LIPUS enhanced mineralization of force-treated OCCM30 cells, as indicated by ALP and alizarin red staining, upregulated mRNA expression of mineralization-related genes, and increased protein expression of mineralization markers. Mechanistically, LIPUS activated YAP1 signaling via the cytoskeleton-Lamin A/C pathway, supported by immunofluorescence and Western blot analysis. This study demonstrates that LIPUS promotes mineralization in force-treated cementoblasts and reduces OIIRR by activating YAP1 through the cytoskeletal-Lamin A/C signaling pathway. These findings provide fresh insights into how LIPUS benefits orthodontic treatment and suggest potential strategies for preventing and treating OIIRR.

Engineered Immunomodulatory Nanoparticles Inhibit Root Resorption and Ankylosis

IntroductionExternal root resorption following avulsion injury is a complex process wherein differentiation of macrophages (Mϕ) to multinucleated osteoclasts is temporally regulated by resident periodontal fibroblasts (PDLF). The current study aims to assess the effect of engineered bioactive chitosan nanoparticles (CSNP), sustained released dexamethasone conjugated CSNP (CS-DEX) and CSNP functionalized with photosensitizer Rose Bengal (CSRB) for application in root resorption using an in-vitro PDLF-Mϕ direct coculture model and in-vivo delayed reimplantation model. MethodsPDLF-Mϕ direct coculture system was exposed to lipopolysaccharide (LPS), macrophage colony stimulating factor, receptor activator of nuclear factor kappa β ligand with or without CSNP/CS-DEX for 7 days. Clastic differentiation was assessed by tartrate resistant acid phosphatase (TRAP) staining on day 7. On day 2 and 7, immunofluorescence analysis was conducted to assess the expression of Mϕ polarization markers (CD80, CD206), multinucleation markers (NFATc1, STAT6) in Mϕ and matricellular protein periostin in PDLF and cytokine profiling in cell culture supernatants. Delayed replantation model with extraoral air dry/LPS exposure for 1h followed by root surface treatment with CS-DEX/CSRB was used in Wistar rats. After 21 days, rats were euthanized for histologic and immunofluorescence analysis. Statistical analysis one-way ANOVA with Tukey's multiple comparisons was used to analyze the data (P < .05). ResultsCS-DEX significantly reduced TRAP+ multinucleated cells and CSNP treatment showed no TRAP+ cells. Immunofluorescence analysis showed that CSNP/CS-DEX reduced CD80, NFATc1 and STAT6 expression and increased periostin as expressed by fluorescence intensity. CSNP/CS-DEX significantly reduced TNFα, MMP9 and increased IL10, TGFβ1. Osteoprotegerin was upregulated only by CSNP. Root surface treatment in delayed replantation model showed that CS-DEX and CSRB substantially reduced the degree of resorption and ankylosis. Further, CD80, CD206, and MMP2 expression in groups with root surface treatment with CS-DEX and CSRB was lower than airdry/LPS group and similar to healthy control and NFATc1, STAT6, and MMP9 expressions were lower than healthy control. ConclusionThe engineered nanosized immunomodulatory bioactive materials chitosan nanoparticles functionalized with photosensitizer and dexamethasone effectively reduced the clastic differentiation of Mϕ in in-vitro coculture and minimized the resorption and ankylosis in a delayed reimplantation model. These biomaterials have the potential to serve as root modification agents, promoting favorable healing outcomes in cases of dental avulsion.