ß-catenin inhibition disrupts the homeostasis of osteogenic/adipogenic differentiation leading to the development of glucocorticoid-induced osteonecrosis of the femoral head.

Glucocorticoid-induced osteonecrosis of the femoral head (GONFH) is a common refractory joint disease characterized by bone damage and the collapse of femoral head structure. However, the exact pathological mechanisms of GONFH remain unknown. Here, we observed abnormal osteogenesis and adipogenesis associated with decreased ß-catenin in the necrotic femoral head of GONFH patients. In vivo and in vitro studies further revealed that glucocorticoid exposure disrupted osteogenic/adipogenic differentiation of bone marrow mesenchymal cells (BMSCs) by inhibiting ß-catenin signaling in glucocorticoid-induced GONFH rats. Col2+ lineage largely contributes to BMSCs and was found an osteogenic commitment in the femoral head through 9 mo of lineage trace. Specific deletion of ß-catenin gene (Ctnnb1) in Col2+ cells shifted their commitment from osteoblasts to adipocytes, leading to a full spectrum of disease phenotype of GONFH in adult mice. Overall, we uncover that ß-catenin inhibition disrupting the homeostasis of osteogenic/adipogenic differentiation contributes to the development of GONFH and identify an ideal genetic-modified mouse model of GONFH.

Liquiritin reduces chondrocyte apoptosis through P53/PUMA signaling pathway to alleviate osteoarthritis.

AIMS: The main pathological features of osteoarthritis (OA) include the degeneration of articular cartilage and a decrease in matrix synthesis. Chondrocytes, which contribute to matrix synthesis, play a crucial role in the development of OA. Liquiritin, an effective ingredient extracted from Glycyrrhiza uralensis Fisch., has been used for over 1000 years to treat OA. This study aims to investigate the impact of liquiritin on OA and its underlying mechanism. MATERIALS AND METHODS: Gait and hot plate tests assessed mouse behavior, while Micro-CT and ABH/OG staining observed joint morphological changes. The TUNEL kit detected chondrocyte apoptosis. Western blot and immunofluorescence techniques determined the expression levels of cartilage metabolism markers COL2 and MMP13, as well as apoptosis markers caspase3, bcl2, P53, and PUMA. KEGG analysis and molecular docking technology were used to verify the relationship between liquiritin and P53. KEY FINDINGS: Liquiritin alleviated pain sensitivity and improved gait impairment in OA mice. Additionally, we found that liquiritin could increase COL2 levels and decrease MMP13 levels both in vivo and in vitro. Importantly, liquiritin reduced chondrocyte apoptosis induced by OA, through decreased expression of caspase3 expression and increased expression of bcl2 expression. Molecular docking revealed a strong binding affinity between liquiritin and P53. Both in vivo and in vitro studies demonstrated that liquiritin suppressed the expression of P53 and PUMA in cartilage. SIGNIFICANCE: This indicated that liquiritin may alleviate OA progression by inhibiting the P53/PUMA signaling pathway, suggesting that liquiritin is a potential strategy for the treatment of OA.

Protective effects of Shensuitongzhi formula on intervertebral disc degeneration via downregulation of NF-κB signaling pathway and inflammatory response.

Low back pain (LBP) is a common orthopedic disease over the world. Lumbar intervertebral disc degeneration (IDD) is regarded as an important cause of LBP. Shensuitongzhi formula (SSTZF) is a drug used in clinical treatment for orthopedic diseases. It has been found that SSTZF can have a good treatment for IDD. But the exact mechanism has not been clarified. The results showed that SSTZF protects against LSI-induced degeneration of cartilage endplates and intervertebral discs. Meanwhile, SSTZF treatment dramatically reduces the expression of inflammatory factor as well as the expression of catabolism protein and upregulates the expression of anabolism protein in LSI-induced mice. In addition, SSTZF delayed the progression of LSI-induced IDD via downregulation the level of NF-κB signaling key gene RELA and phosphorylation of key protein P65 in endplate chondrocytes. Our study has illustrated the treatment as well as the latent mechanism of SSTZF in IDD.

Aucubin Alleviates Intervertebral Disc Degeneration by Repressing NF-κB-NLRP3 Inflammasome Activation in Endplate Chondrocytes.

Background: Intervertebral disc degeneration (IDD) is a prevalent degenerative disease and often recognized as the primary cause of lower back pain (LBP). Aucubin (Au) is a natural compound with anti-inflammatory properties in various diseases. The present study aimed to confirm the therapeutic effect of Au on IDD and explore its potential mechanism in vivo and in vitro. Methods: The process of IDD was simulated using the lumbar spine instability (LSI) model. In vivo, the therapeutic effect of Au on LSI-induced mice was evaluated by micro-CT and histomorphometry. Additionally, immunohistochemistry was applied to detect the cartilage metabolism and inflammasome activation in endplate. In vitro, the cytotoxicity of Au on ATDC5 cells was detected by Cell Counting Kit-8 (CCK-8), and the biological effects of Au were evaluated by Quantitative Real-time PCR (qRT-PCR) and Western blotting. Results: Micro-CT analysis showed that Au administration significantly alleviated LSI-induced disc volume narrowing and endplate cartilage degeneration, which was further supported by Alcian Blue Hematoxylin/Orange G (ABH/OG) staining. Immunohistochemistry results verified that Au could increase the expression of Col2α1 and Aggrecan, reduce the expression of Mmp-13, and attenuate the degradation of the endplate extracellular matrix (ECM). Mechanistically, we found that Au treatment, both in vivo and in vitro, significantly inhibited NF-κB-NLRP3 inflammasome activation in chondrocytes as determined by the decreased expression of p-P65, NLRP3, and Caspase-1. Discussion: Taken together, our findings have demonstrated for the first time that Au treatment ameliorated the degeneration of cartilage endplates in IDD may by inhibiting NF-κB-NLRP3 inflammasome activation in chondrocytes and provided a potential candidate for the treatment of IDD.

Ambient PM2.5 Exposure and Bone Homeostasis: Analysis of UK Biobank Data and Experimental Studies in Mice and in Vitro.

BACKGROUND: Previous evidence has identified exposure to fine ambient particulate matter (PM2.5) as a leading risk factor for adverse health outcomes. However, to date, only a few studies have examined the potential association between long-term exposure to PM2.5 and bone homeostasis. OBJECTIVE: We sought to examine the relationship between long-term PM2.5 exposure and bone health and explore its potential mechanism. METHODS: This research included both observational and experimental studies. First, based on human data from UK Biobank, linear regression was used to explore the associations between long-term exposure to PM2.5 (i.e., annual average PM2.5 concentration for 2010) and bone mineral density [BMD; i.e., heel BMD (n=37,440) and femur neck and lumbar spine BMD (n=29,766)], which were measured during 2014-2020. For the experimental animal study, C57BL/6 male mice were assigned to ambient PM2.5 or filtered air for 6 months via a whole-body exposure system. Micro-computed tomography analyses were applied to measure BMD and bone microstructures. Biomarkers for bone turnover and inflammation were examined with histological staining, immunohistochemistry staining, and enzyme-linked immunosorbent assay. We also performed tartrate-resistant acid phosphatase (TRAP) staining and bone resorption assay to determine the effect of PM2.5 exposure on osteoclast activity in vitro. In addition, the potential downstream regulators were assessed by real-time polymerase chain reaction and western blot. RESULTS: We observed that long-term exposure to PM2.5 was significantly associated with lower BMD at different anatomical sites, according to the analysis of UK Biobank data. In experimental study, mice exposed long-term to PM2.5 exhibited excessive osteoclastogenesis, dysregulated osteogenesis, higher tumor necrosis factor-alpha (TNF-α) expression, and shorter femur length than control mice, but they demonstrated no significant differences in femur structure or BMD. In vitro, cells stimulated with conditional medium of PM2.5-stimulated macrophages had aberrant osteoclastogenesis and differences in the protein/mRNA expression of members of the TNF-α/Traf6/c-Fos pathway, which could be partially rescued by TNF-α inhibition. DISCUSSION: Our prospective observational evidence suggested that long-term exposure to PM2.5 is associated with lower BMD and further experimental results demonstrated exposure to PM2.5 could disrupt bone homeostasis, which may be mediated by inflammation-induced osteoclastogenesis. https://doi.org/10.1289/EHP11646.

Disruption of Col9a2 expression leads to defects in osteochondral homeostasis and osteoarthritis-like phenotype in mice.

Background/Objective: As one of the branched chains of Type IX collagen (Col9), Collagen IX alpha2 (Col9a2) has been reported to be associated with several orthopedic conditions. However, the relationship between Col9a2 and knee osteoarthritis (KOA) remains to be elucidated. Methods: To probe the relationship between Col9a2 and KOA, we performed a systematic analysis of Col9a2-deficient (Col9a2-/-) mice using whole-mount skeletal staining, Micro-CT (µCT), biomechanics, histomorphometry, immunohistochemistry (IHC), immunofluorescence (IF) and Elisa. Results: We found that the subchondral bone (SCB) in the knee joint of Col9a2-/- mice became sparse and deformed in the early stage, with altered bone morphometric parameters, reduced load-bearing capacity, dysfunctional bone homeostasis (decreased osteogenesis capacity and elevated bone resorption capacity), diminished cartilage proteoglycans and disrupted cartilage extracellular matrix (ECM) anabolism and catabolism compared with the Col9a2+/+ mice. In the late stage, the cartilage degeneration in Col9a2-/- mice were particularly pronounced compared to Col9a2+/+ mice, as evidenced by severe cartilage destruction and a marked reduction in cartilage thickness and area. Conclusion: Overall, Col9a2 is essential for maintaining osteochondral homeostasis in the knee joint of mice, and the absence of this gene is accompanied by distinct sclerosis of the SCB and a reduction in load-bearing capacity; in the late stage, in the lack of SCB stress inhibition, excessive load is consistently exerted on the cartilage, ultimately leading to osteoarthritic-like articular cartilage damage.

Glucocorticoid-induced activation of NOX/ROS/NF-κB signaling in MSCs contributes to the development of GONFH.

BACKGROUND: This study aimed to investigate the pathogenic factors of glucocorticoids (GCs)-induced osteonecrosis of the femoral head (GONFH) and its underlying pathogenesis in vivo and in vitro. METHODS: Radiographical (µCT) scanning, histopathological, immunohistochemical, reactive oxygen species (ROS) and tunel staining were conducted on GONFH patients and rats. ROS, tunel, flow cytometry, alkaline phosphatase, Oil red O staining, reverse transcription­quantitative PCR and western blotting were applied to elucidate the exact pathogenesis mechanism. RESULTS: Clinical and animal studies demonstrated increased levels of ROS, aggravated oxidative stress (OS) microenvironment, augmented apoptosis and imbalance in osteogenic/lipogenic in the GONFH group compared to the control group. The fate of mesenchymal stem cells (MSCs) directed by GCs is a crucial factor in determining GONFH. In vitro studies further revealed that GCs promote excessive ROS production through the expression of NOX family proteins, leading to a deterioration of the OS microenvironment in MSCs, ultimately resulting in apoptosis and imbalance in osteogenic/lipogenic differentiation. Furthermore, our results confirmed that the NOX inhibitor-diphenyleneiodonium chloride and the NF-κB inhibitor-BAY 11-7082 ameliorated apoptosis and osteogenic/lipogenic differentiation imbalance of MSCs induced by an excess of GCs. CONCLUSION: We demonstrated for the first time that the aggravation of the OS microenvironment in MSCs caused by high doses of GCs leading to apoptosis and differentiation imbalance is a crucial factor in the pathogenesis of GONFH, mediated through activating the NOX/ROS/NF-κB signaling pathway.

Chondroprotective Mechanism of Eucommia ulmoides Oliv.-Glycyrrhiza uralensis Fisch. Couplet Medicines in Knee Osteoarthritis via Experimental Study and Network Pharmacology Analysis.

Background: Knee osteoarthritis (KOA) is the primary prevalent disabling joint disorder among osteoarthritis (OA), and there is no particularly effective treatment at the clinic. Traditional Chinese medicine (TCM) herbs, such as Eucommia ulmoides Oliv. and Glycyrrhiza uralensis Fisch. (E.G.) couplet medicines, have been reported to exhibit beneficial health effects on KOA, exact mechanism of E.G. nevertheless is not fully elucidated. Purpose: We assess the therapeutic effects of E.G. on KOA and explore its underlying molecular mechanism. Methods: UPLC-Q-TOF/MS technique was used to analyze the active chemical constituents of E.G. The destabilization of the medial meniscus model (DMM) was employed to evaluate the chondroprotective action of E.G. in KOA mice using histomorphometry, µCT, behavioral testing and immunohistochemical staining. Additionally, network pharmacology and molecular docking were used to predict potential targets for anti-KOA activities of E.G., which was further verified through in vitro experiments. Results: In vivo studies have shown that E.G. could significantly ameliorate DMM-induced KOA phenotypes including subchondral bone sclerosis, cartilage degradation, gait abnormality and thermal pain reaction sensibility. E.G. treatment could also promote extracellular matrix synthesis to protect articular chondrocytes, which was indicated by Col2 and Aggrecan expressions, as well as reducing matrix degradation by inhibiting MMP13 expression. Interestingly, network pharmacologic analysis showed that PPARG might be a therapeutic center. Further study proved that E.G.-containing serum (EGS) could up-regulate PPARG mRNA level in IL-1ß-induced chondrocytes. Notably, significant effects of EGS on the increment of anabolic gene expressions (Col2, Aggrecan) and the decrement of catabolic gene expressions (MMP13, Adamts5) in KOA chondrocytes were abolished due to the silence of PPARG. Conclusion: E.G. played a chondroprotective role in anti-KOA by inhibiting extracellular matrix degradation, which might be related to PPARG.

Protein phosphatase PPM1A inhibition attenuates osteoarthritis via regulating TGF-ß/Smad2 signaling in chondrocytes.

TGF-ß signaling is crucial for modulating osteoarthritis (OA), and protein phosphatase magnesium-dependent 1A (PPM1A) has been reported as a phosphatase of SMAD2 and regulates TGF-ß signaling, while the role of PPM1A in cartilage homeostasis and OA development remains largely unexplored. In this study, we found increased PPM1A expression in OA chondrocytes and confirmed the interaction between PPM1A and phospho-SMAD2 (p-SMAD2). Importantly, our data show that PPM1A KO substantially protected mice treated with destabilization of medial meniscus (DMM) surgery against cartilage degeneration and subchondral sclerosis. Additionally, PPM1A ablation reduced the cartilage catabolism and cell apoptosis after the DMM operation. Moreover, p-SMAD2 expression in chondrocytes from KO mice was higher than that in WT controls with DMM induction. However, intraarticular injection with SD-208, repressing TGF-ß/SMAD2 signaling, dramatically abolished protective phenotypes in PPM1A-KO mice. Finally, a specific pharmacologic PPM1A inhibitor, Sanguinarine chloride (SC) or BC-21, was able to ameliorate OA severity in C57BL/6J mice. In summary, our study identified PPM1A as a pivotal regulator of cartilage homeostasis and demonstrated that PPM1A inhibition attenuates OA progression via regulating TGF-ß/SMAD2 signaling in chondrocytes and provided PPM1A as a potential target for OA treatment.

Inflammation-Mediated Aberrant Glucose Metabolism in Subchondral Bone Induces Osteoarthritis.

Osteoarthritis (OA) is an entire joint disease with pathological alteration in both articular cartilage and subchondral bone. It has been recognized recently the association between metabolic syndrome and OA, particularly glucose metabolism in regulation of articular cartilage homeostasis and joint integrity. Whereas the role of glucose metabolism in subchondral bone sclerosis remains largely unknown during pathogenesis of OA. Consistent with common OA features, we observed subchondral bone sclerosis and abnormal bone remodeling in human OA joints and murine OA joints as reflected by hyperactive bone resorption and overall bone formation which was measured via dynamic histomorphometry. Osx-CreER;tdTomato mice also displayed the similar overall bone formation under injury-induced OA condition. Immunohistochemistry further revealed increased IL-1ß expression in human and murine OA subchondral bone. Given the inflammatory environment in joints under OA condition, we treated MC3T3-E1 cell, a pre-osteoblast cell line, with IL-1ß in this study and demonstrated that IL-1ß treatment could stimulate the cell osteogenic differentiation and meanwhile upregulate glycolysis and oxidative phosphorylation in cell cultures. More importantly, intraperitoneal injection of 2-deoxy-D-glucose (2-DG) and oligomycin (OGM), respectively, suppressed the subchondral bone glycolysis and oxidative phosphorylation in mice. Consequently, 2-DG and OGM treatment attenuated abnormal osteoblast differentiation and protected against aberrant bone formation in subchondral bone and articular cartilage degradation in wildtype mice following with joint injury. Collectively, these data strongly suggest glycolysis and oxidative may serve as important therapeutic targets for OA treatment.

Glycyrrhizic acid alters the hyperoxidative stress-induced differentiation commitment of MSCs by activating the Wnt/ß-catenin pathway to prevent SONFH.

This study aimed to examine the in vivo and in vitro therapeutic effects of glycyrrhizic acid (GA) on steroid-induced osteonecrosis of the femoral head (SONFH), which is caused by the overuse of glucocorticoids (GCs). Clinically, we identified elevated oxidative stress (OS) levels and an imbalance in osteolipogenic homeostasis in SONFH patients compared to femoral neck fracture (FNF) patients. In vivo, we established experimental SONFH in rats via lipopolysaccharides (LPSs) combined with methylprednisolone (MPS). We showed that GA and Wnt agonist-S8320 alleviated SONFH, as evidenced by the reduced microstructural and histopathological alterations in the subchondral bone of the femoral head and the decreased levels of OS in rat models. In vitro, GA reduced dexamethasone (Dex)-induced excessive NOX4 and OS levels by activating the Wnt/ß-catenin pathway, thereby promoting the osteogenic differentiation of mesenchymal stem cells (MSCs) and inhibiting lipogenic differentiation. In addition, GA regulated the expression levels of the key transcription factors downstream of this pathway, Runx2 and PPARγ, thus maintaining osteolipogenic homeostasis. In summary, we demonstrated for the first time that GA modulates the osteolipogenic differentiation commitment of MSCs induced by excessive OS through activating the Wnt/ß-catenin pathway, thereby ameliorating SONFH.

Mid-term outcomes of microfragmented adipose tissue plus arthroscopic surgery for knee osteoarthritis: A randomized, active-control, multicenter clinical trial.

BACKGROUND: Osteoarthritis (OA) is the most prevalent form of degenerative whole-joint disease. Before the final option of knee replacement, arthroscopic surgery was the most widely used joint-preserving surgical treatment. Emerging regenerative therapies, such as those involving platelet-rich plasma, mesenchymal stem cells, and microfragmented adipose tissue (MFAT), have been pushed to the forefront of treatment to prevent the progression of OA. Currently, MFAT has been successfully applied to treat different types of orthopedic diseases. AIM: To assess the efficacy and safety of MFAT with arthroscopic surgery in patients with knee OA (KOA). METHODS: A randomized, multicenter study was conducted between June 2017 and November 2022 in 10 hospitals in Zhejiang, China. Overall, 302 patients diagnosed with KOA (Kellgren-Lawrence grades 2-3) were randomized to the MFAT group (n = 151, were administered MFAT following arthroscopic surgery), or the control group (n = 151, were administered hyaluronic acid following arthroscopic surgery). The study outcomes were changes in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the visual analog scale (VAS) score, the Lequesne index score, the Whole-Organ Magnetic Resonance Imaging Score (WORMS), and safety over a 24-mo period from baseline. RESULTS: The changes in the WOMAC score (including the three subscale scores), VAS pain score, and Lequesne index score at the 24-mo mark were significantly different in the MFAT and control groups, as well as when comparing values at the posttreatment visit and those at baseline (P < 0.001). The MFAT group consistently demonstrated significant decreases in the WOMAC pain scores and VAS scores at all follow-ups compared to the control group (P < 0.05). Furthermore, the WOMAC stiffness score, WOMAC function score, and Lequesne index score differed significantly between the groups at 12 and 24 mo (P < 0.05). However, no significant between-group differences were observed in the WORMS at 24 mo (P = 0.367). No serious adverse events occurred in both groups. CONCLUSION: The MFAT injection combined with arthroscopic surgery treatment group showed better mid-term clinical outcomes compared to the control group, suggesting its efficacy as a therapeutic approach for patients with KOA.

Elucidation of the Underlying Mechanism of Gujian Oral Liquid Acting on Osteoarthritis through Network Pharmacology, Molecular Docking, and Experiment.

Gujian oral liquid (GJ), a traditional herbal formula in China, has been widely used to treat patients with osteoarthritis (OA). Nevertheless, the active component and potential mechanism of GJ are not fully elucidated. Thus, we investigate the effect of GJ and explore its underlying mechanism on OA through network pharmacology and experimental validation. First, a total of 175 bioactive compounds were identified, and 134 overlapping targets were acquired after comparing the targets of the GJ with those of OA. 8 hub targets, including IL6 and AKT1, were obtained in PPI network analysis. Then, we built up GJ-target-OA network and protein-protein interaction (PPI) network, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The results underlined inflammatory tumor necrosis factor (TNF) as a promising signaling pathway of GJ for OA treatment. Moreover, molecular docking also verified the top two active compounds had direct bindings with the top three target genes. Finally, we verified the effect of GJ on OA in vivo and in vitro. In vivo experiments validated that GJ not only significantly attenuated OA phenotypes including articular cartilage degeneration and subchondral bone sclerosis but also reduced the expressions of tumor necrosis factor-α (TNF-α) and p-p65 in articular chondrocytes. Besides, GJ serum also had a protective effect on chondrocytes against inflammation caused by TNF-α in vitro. Hence, our study predicted and verified that GJ could exert anti-inflammation and anticatabolism effects partially via regulating TNF-α/NF-kappa B (NF-κB) signaling.

N-Butanol Extract of Modified You-Gui-Yin Attenuates Osteoclastogenesis and Ameliorates Osteoporosis by Inhibiting RANKL-Mediated NF-κB Signaling.

Postmenopausal Osteoporosis (PMOP) is the most prevalent primary osteoporosis, attributable to an imbalance in osteoblast and osteoclast activity. Modified You-Gui-Yin (MYGY), a traditional Chinese herbal formula, is able to effectively treat PMOP, while the critical components and pharmacological mechanisms of MYGY are still unclear. In this study, we aimed to investigate the therapeutic effects and underlying mechanisms of N-butanol extract of MYGY (MYGY-Nb) in ovariectomized (OVX)-induced osteoporosis mice. Histological staining and micro-computed tomography (µCT) analysis showed that MYGY-Nb was more effective in the suppression of OVX-induced bone loss than MYGY original formula. Subsequently, liquid chromatography and mass spectrometry analysis identified 16 critical compounds of MYGY-Nb and some of them are reported to affect osteoclast functions. Furthermore, in vivo and in vitro experiments demonstrated that MYGY-Nb significantly attenuated osteoclastogenesis by down-regulating RANKL-mediated NF-κB signaling. In conclusion, our study indicated that MYGY-Nb suppresses NF-κB signaling and osteoclast formation to mitigate bone loss in PMOP, implying that MYGY-Nb and its compounds are potential candidates for development of anti-PMOP drugs.

Col9a2 gene deletion accelerates the degeneration of intervertebral discs.

As an essential component of the extracellular matrix (ECM) in cartilage, the α2 chain of type IX collagen (Col9a2), has been implicated in human intervertebral disc degeneration (IVDD). However, the precise role of the Col9a2 gene in the pathogenesis of IVDD has remained elusive. In the present study, the spines of Col9a2-deficient (Col9a2-/-) mice were systematically analyzed and compared with wild-type control mice using micro-CT (µCT), histomorphology, immunofluorescence, immunohistochemistry and reverse transcription-quantitative PCR (RT-qPCR). µCT analysis revealed that endplate (EP) osteochondral remodeling in the Col9a2-/- group was accompanied by a significant increase in EP porosity. Likewise, histopathological staining at 12 weeks revealed that the Col9a2-/- mice exhibited a marked early-stage IVDD phenotype, including EP sclerosis, calcification and annulus fibrosus rupture. The immunofluorescence results indicated that Col9a2 was extensively expressed in the IVDs, whereas it was barely detectable in Col9a2-/- mice. Immunohistochemical and RT-qPCR analyses demonstrated that the expression levels of Col2a1 and Aggrecan in the IVDs of Col9a2-/- mice were significantly decreased. In addition, the levels of Mmp13, ADAM metallopeptidase with thrombospondin type 1 motif 5, Col10a1 and Runx family transcription factor 2 were significantly elevated. These results suggested that deletion of the Col9a2 gene led to osteochondral remodeling of cartilage EP and suppressed ECM synthesis, accelerating matrix degradation and chondrocyte hypertrophy in the IVD tissue.

Fractions of Shen-Sui-Tong-Zhi Formula Enhance Osteogenesis Via Activation of ß-Catenin Signaling in Growth Plate Chondrocytes.

Background: Shen-sui-tong-zhi formula (SSTZF) has been used to treat osteoporosis for decades and shows excellent clinical efficacy. This article aims to explore the optimal anti-osteoporotic ingredient and its precise mechanisms in mice models. Methods: In this study, we first screened the optimal anti-osteoporosis fraction of SSTZF extract in vivo, and then further explored the mechanism of its effects both in vivo and in vitro. Ten-week-old female C57BL/6J mice were administrated with each fraction of SSTZF. At 10 weeks after ovariectomy (OVX), femurs were collected for tissue analyses, including histology, micro-CT, biomechanical tests, and immunohistochemistry for ALP, FABP4, and ß-catenin. Additionally, we also evaluated the mRNA expression level of ALP and FABP4 and the protein expression level of ß-catenin after being treated with SSTZF extract in C3H10T1/2 cells. Moreover, we investigated the anti-osteoporosis effect of SSTZF extract on mice with ß-catenin conditional knockout in growth plate chondrocytes (ß-catenin Gli1ER mice) through µCT, histology, and immunohistochemistry analyzes. Results: At 10 weeks after treatment, osteoporosis-like phenotype were significantly ameliorated in SSTZF n-butanol extract (SSTZF-NB) group mice, as indicated by increased trabecular bone area and ALP content, and decreased lipid droplet area and FABP4 content. No such improvements were observed after being treated with other extracts, demonstrating that SSTZF-NB is the optimal anti-osteoporosis fraction. Additionally, the elevated ß-catenin was revealed in both OVX mice and C3H10T1/2 cells with SSTZF-NB administered. Furthermore, a significant osteoporosis-like phenotype was observed in ß-catenin Gli1ER mice as expected. However, SSTZF-NB failed to rescue the deterioration in ß-catenin Gli1ER mice, no significant re-upregulated ALP and downregulated FABP4 were observed after being treated with SSTZF-NB, demonstrating that SSTZF-NB prevents bone loss mainly via ß-catenin signaling. Conclusion: SSTZF-NB enhances osteogenesis mainly via activation of ß-catenin signaling in growth plate chondrocytes. SSTZF-NB is the optimal anti-osteoporosis fraction of SSTZF and it can be considered a salutary alternative therapeutic option for osteoporosis.

Osteoking Decelerates Cartilage Degeneration in DMM-Induced Osteoarthritic Mice Model Through TGF-ß/smad-dependent Manner.

Osteoarthritis (OA) is a common disease characterized by cartilage degeneration. In recent years much attention has been paid to Traditional Chinese Medicine (TCM) since its treatments have shown efficacy for ameliorating cartilage degradation with mild side effects. Osteoking is a TCM prescription that has long been used in OA treatment. However, the exact mechanism of Osteoking are not fully elucidated. In the current study, destabilization of the medial meniscus (DMM)-induced OA mice was introduced as a wild type animal model. After 8 weeks of administration of Osteoking, histomorphometry, OARSI scoring, gait analysis, micro-CT, and immunohistochemical staining for Col2, MMP-13, TGFßRII and pSmad-2 were conducted to evaluate the chondroprotective effects of Osteoking in vivo. Further in vitro experiments were then performed to detect the effect of Osteoking on chondrocytes. TGFßRIICol2ER transgenic mice were constructed and introduced in the current study to validate whether Osteoking exerts its anti-OA effects via the TGF-ß signaling pathway. Results demonstrated that in wild type DMM mice, Osteoking ameliorated OA-phenotype including cartilage degradation, subchondral bone sclerosis, and gait abnormality. Col2, TGFßRII, and pSmad-2 expressions were also found to be up-regulated after Osteoking treatment, while MMP-13 was down-regulated. In vitro, the mRNA expression of MMP-13 and ADAMTS5 decreased and the mRNA expression of Aggrecan, COL2, and TGFßRII were up-regulated after the treatment of Osteoking in IL-1ß treated chondrocytes. The additional treatment of SB505124 counteracted the positive impact of Osteoking on primary chondrocytes. In TGFßRIICol2ER mice, spontaneous OA-liked phenotype was observed and treatment of Osteoking failed to reverse the OA spontaneous progression. In conclusion, Osteoking ameliorates OA progression by decelerating cartilage degradation and alleviating subchondral bone sclerosis partly via the TGF-ß signaling pathway.

Chlorogenic Acid retards cartilaginous endplate degeneration and ameliorates intervertebral disc degeneration via suppressing NF-κB signaling.

AIMS: Intervertebral Disc Degeneration (IDD) is a key factor involved in low back pain (LBP) which affects approximately 540 million individuals worldwide. Chlorogenic Acid (CGA), a natural compound, exerts anti-inflammatory property in several diseases. Here, we aim to investigate the biological effect of CGA on IDD and explore the underlying mechanism. MATERIALS AND METHODS: Lumbar spine instability (LSI) model in mice was utilized to mimic process of IDD. The effects of CGA in response to LSI were evaluated by luminescent imaging, micro-CT, histomorphology, and immunohistochemistry in vivo. Besides, the cytotoxicity of CGA on chondrocytes was detected by cell counting kit-8 (CCK-8) and the biological effects were assessed by polymerase chain reaction (PCR) in vitro. KEY FINDINGS: We found that CGA treatment dramatically suppressed the NF-κB activity in LSI mice. Moreover, administration of CGA mitigated cartilaginous endplate degeneration and postponed IDD development accompanying a decrease of inflammatory and catabolic mediators. Specifically, CGA ameliorated endplate degeneration might be related to its protective effects against endplate chondrocytes apoptosis and trans-differentiation. We further elucidated that CGA exerted these biological effects mainly by repressing NF-κB signaling in cartilage endplate. SIGNIFICANCE: Our study has illustrated, for the first time, the curative effects as well as the latent mechanism of CGA in IDD and our results suggested that CGA administration might be used as an alternative therapy for IDD.

Defining disease progression in Chinese mainland people: Association between bone mineral density and knee osteoarthritis.

OBJECTIVE: To evaluate change in bone mineral density (BMD) during development of knee osteoarthritis (OA) in elderly Chinese community residents. Further, to monitor disease progression by recording speed of sound (SOS), one parameter of BMD provided by quantitative ultrasound measurement. METHODS: A total of 4173 community residents of the Chinese mainland were organized to complete questionnaires and relevant measurements, including anthropometry, radiology and quantitative ultrasound (QUS). SOS measurements of the distal radius were acquired using QUS measurements. The Kellgren-Lawrence (KL) grade of knee OA was evaluated by two experienced radiographers using X-rays. Finally, a general linear models analysis was performed to determine potential relationships. Further, the area under the receiver operating characteristic curve (ROC AUC) was applied to assess the distinction model. RESULTS: The SOS score in the OA group was significantly lower than that in the control group (p â€‹< â€‹0.001). However, after adjustment for age and body mass index (BMI), no significant difference was observed in the male population (p â€‹ï¼ â€‹0.841), while a significantly lower SOS score presented in knee OA participants in the female population (p â€‹ï¼ â€‹0.033). A turning point in SOS scores, from increasing to decreasing trends, occurred around KL grade 2; the SOS score gradually increased with progression in participants from KL grades 0 to 2, whereas the SOS score presented a significant decrease in participants with KL grades 3 and 4. The AUC for the model to distinguish OA progression was 0.891. CONCLUSION: There was a non-linear and stage-specific association between SOS score and knee OA, which presented a positive relationship in early stages, but a negative relationship in advanced stages. A decline of SOS score in knee OA patients in early stages should alert clinicians to the possibility of disease progression. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: In the present study, the relationship between OA and BMD had established by SOS. The results suggested that close monitoring of SOS in elderly Chinese communities residents with knee OA could alert disease progression involvement by an easily accessible method, and help early referral to orthopedist consultation for further examination and treatment.

Platelet-rich plasma promotes bone formation, restrains adipogenesis and accelerates vascularization to relieve steroids-induced osteonecrosis of the femoral head.

Steroid-associated necrosis of the femoral head (SANFH) is one of the most common and refractory chronic diseases with increasing incidence. The typical pathological changes of SANFH include decreased osteogenic differentiation, enhanced intramedullary adipocytes deposition and impaired osseous circulation. In this study, we investigated the effects and potential mechanisms of Platelet-rich plasma (PRP) on SANFH. Sixty Sprague-Dawley rats were randomly divided into the control, PRP donor, model, and PRP groups. Compared to the model group, PRP treatment significantly increased the hemorheological indexes and serum levels of bone gla-protein (BGP) and vascular endothelial growth factor (VEGF), while decreased the levels of triglyceride (TG) and total cholesterol (TC). Meanwhile, Micro-CT and histopathological stain (Hematoxylin-eosin and Alcian blue-hematoxylin/orange G staining) were performed on the femoral head for morphological and histopathological evaluation, indicating that bone trabecular microstructure and bone mineral density (BMD) were significantly improved after PRP treatment. Immunohistochemical analysis revealed that PRP remarkably up-regulated the expression of osteogenic markers including ß-catenin and alkaline phosphatase (ALP), angiogenic markers containing VEGF and platelet endothelial cell adhesion molecule-1 (CD31), while down-regulated adipogenic markers involving fatty acid-binding protein (FABP-4), and peroxisome proliferator-activated receptor gamma (PPAR-γ) in SANFH rat models. In summary, for the first time, PRP was demonstrated to prevent the development of SANFH through stimulating bone formation and vascularization as well as retarding adipogenesis.