Tanshinol Rescues the Impaired Bone Formation Elicited by Glucocorticoid Involved in KLF15 Pathway

Circ-AARS plays an important role during the odontogenic differentiation of dental pulp stem cells by modulating miR-24-3p/KLF6 expression

BACKGROUND

Circular RNAs (circRNAs) play a crucial role in stem cell-based tooth regeneration. However, the functions and underlying mechanisms of circRNAs in tooth regeneration from human dental pulp stem cells (DPSCs) remain largely unclear.

METHODS

In this study, DPSCs were used for odontogenic differentiation. High-throughput sequencing was performed for differential circRNA analysis. A luciferase reporter assay was conducted to confirm the downstream target of the circRNA, circ-AARS. We then constructed vectors and siRNAs for overexpressing and silencing circ-AARS, miR-24-3p, and Krüppel-like factor 6 (KLF6) and transfected them into DPSCs. Alkaline phosphatase staining, Alizarin Red S staining, western blotting assay, and quantitative reverse transcription-polymerase chain reaction were used to explore the underlying mechanisms of circ-AARS. Finally, a heterotopic bone model was utilized to reveal the regulating effects of circ-AARS.

RESULTS

High-throughput sequencing analysis showed that circ-AARS plays an important role during the odontogenic differentiation of DPSCs. Downregulation of circ-AARS inhibited the odontogenic differentiation of DPSCs; however, circ-AARS overexpression promoted their odontogenic differentiation. Bioinformatics analysis and luciferase reporter assay confirmed that both miR-24-3p and KLF6 were the downstream targets of circ-AARS. miR-24-3p downregulation or KLF6 overexpression restored the odontogenic differentiation ability of DPSCs after circ-AARS silencing. KLF6 upregulation restored the odontogenic differentiation ability of DPSCs after KLF6 overexpression. The heterotopic bone model confirmed that circ-AARS overexpression promoted the odontoblastic differentiation of DPSCs.

CONCLUSION

The present study showed that circ-AARS can promote the odontoblastic differentiation of DPSCs by increasing KLF6 expression and sponging miR-24-3p. Taken together, the results indicate that circ-AARS may be a potential positive regulator of odontoblastic differentiation of DPSCs.

Salvia miltiorrhiza in osteoporosis: a review of its phytochemistry, traditional clinical uses and preclinical studies (2014-2024)

Osteoporosis becomes a global public health concern due to its rising prevalence and substantial impact on life quality. Salvia miltiorrhiza Bunge (Salviae Miltiorrhizae Radix et Rhizoma, SM) has been firstly recorded in Shen Nong's Herbal Classic, and is frequently prescribed in conjunction with other herbs for the management of osteoporosis. This systematic review aims to comprehensively analyze the recent advances of SM on osteoporosis in traditional Chinese clinical uses and preclinical investigations. Literature encompassing pertinent studies were systematically retrieved across multiple databases, including the PubMed, Web of Science, Chinese National Knowledge Infrastructure, Chinese VIP Database, and Chinese Biomedical Literature Database. Original investigations spanning from February 2014 to March 2024, including traditional Chinese medicine (TCM) clinical trials and preclinical studies, were employed to analyze the effects and actions of SM on osteoporosis. Thirty-eight TCM clinical trials were identified to employ SM in combination with other herbs for the management of primary and secondary osteoporosis. The overall efficacy was between 77% and 96.67%. Forty preclinical studies were identified to investigate the effects and actions of SM and/or its ingredients on osteoporosis. The anti-osteoporosis actions of this herb may be attributed to inhibit osteoclastogenesis/bone resorption and promote osteoblastogenesis/osteogenesis. The ethanol extracts and its ingredients (tanshinones) inhibit osteoclastogenesis/bone resorption by inhibiting the MAPK/NF-κB/NFATc1 signaling pathway and cathepsin K-induced collagen degradation. Both ethanol extracts (tanshinones) and water extracts (Sal B and tanshinol) contribute to osteoblastogenesis by promoting osteogenesis and angiogenesis via activation of the Wnt/β-catenin/VEGF and ERK/TAZ pathways, and eliminating ROS production targeting Nrf2/ARE/HO-1 pathway. In conclusions, SM may offer a novel strategy for osteoporosis management. Well-designed clinical trials are still needed to evaluate the actions of this herb and its ingredients on bone remodeling.

Krüppel-like factors family in health and disease

Krüppel-like factors (KLFs) are a family of basic transcription factors with three conserved Cys2/His2 zinc finger domains located in their C-terminal regions. It is acknowledged that KLFs exert complicated effects on cell proliferation, differentiation, survival, and responses to stimuli. Dysregulation of KLFs is associated with a range of diseases including cardiovascular disorders, metabolic diseases, autoimmune conditions, cancer, and neurodegenerative diseases. Their multidimensional roles in modulating critical pathways underscore the significance in both physiological and pathological contexts. Recent research also emphasizes their crucial involvement and complex interplay in the skeletal system. Despite the substantial progress in understanding KLFs and their roles in various cellular processes, several research gaps remain. Here, we elucidated the multifaceted capabilities of KLFs on body health and diseases via various compliable signaling pathways. The associations between KLFs and cellular energy metabolism and epigenetic modification during bone reconstruction have also been summarized. This review helps us better understand the coupling effects and their pivotal functions in multiple systems and detailed mechanisms of bone remodeling and develop potential therapeutic strategies for the clinical treatment of pathological diseases by targeting the KLF family.

The Role of Traditional Chinese Medicines in the Treatment of Osteoporosis

Osteoporosis (OP) represents a substantial public health issue and is associated with increasing rates of morbidity and mortality. It is characterized by reduced bone mineral density, deterioration of bone tissue quality, disruption of the microarchitecture of bones, and compromised bone strength. These changes may be attributed to the following factors: intercellular communication between osteoblasts and osteoclasts; imbalanced bone remodeling; imbalances between osteogenesis and adipogenesis; imbalances in hormonal regulation; angiogenesis; chronic inflammation; oxidative stress; and intestinal microbiota imbalances. Treating a single aspect of the disease is insufficient to address its multifaceted nature. In recent decades, traditional Chinese medicine (TCM) has shown great potential in the treatment of OP, and the therapeutic effects of Chinese patent drugs and Chinese medicinal herbs have been scientifically proven. TCMs, which contain multiple components, can target the diverse pathogeneses of OP through a multitargeted approach. Herbs such as XLGB, JTG, GSB, Yinyanghuo, Gusuibu, Buguzhi, and Nvzhenzi are among the TCMs that can be used to treat OP and have demonstrated promising effects in this context. They exert their therapeutic effects by targeting various pathways involved in bone metabolism. These TCMs balance the activity of osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells), and they exhibit anti-inflammatory, immunomodulatory, anti-oxidative, and estrogen-like functions. These multifaceted mechanisms underlie the efficacy of these herbs in the management and treatment of OP. Herein, we examine the efficacy of various Chinese herbs and Chinese patent drugs in treating OP by reviewing previous clinical trials and basic experiments, and we examine the potential mechanism of these therapies to provide evidence regarding the use of TCM for treating OP.

KLF transcription factors in bone diseases

Krüppel-like factors (KLFs) are crucial in the development of bone disease. They are a family of zinc finger transcription factors that are unusual in containing three highly conserved zinc finger structural domains interacting with DNA. It has been discovered that it engages in various cell functions, including proliferation, apoptosis, autophagy, stemness, invasion and migration, and is crucial for the development of human tissues. In recent years, the role of KLFs in bone physiology and pathology has received adequate attention. In addition to regulating the normal growth and development of the musculoskeletal system, KLFs participate in the pathological process of the bones and joints and are intimately linked to several skeletal illnesses, such as osteoarthritis (OA), rheumatoid arthritis (RA), osteoporosis (OP) and osteosarcoma (OS). Consequently, targeting KLFs has emerged as a promising therapeutic approach for an array of bone disorders. In this review, we summarize the current literature on the importance of KLFs in the emergence and regulation of bone illnesses, with a particular emphasis on the pertinent mechanisms by which KLFs regulate skeletal diseases. We also discuss the need for KLFs-based medication-targeted treatment. These endeavours offer new perspectives on the use of KLFs in bone disorders and provide prognostic biomarkers, therapeutic targets and possible drug candidates for bone diseases.

Traditional Chinese Medicine formula Bu-Shen-Huo-Xue-Fang (BSHXF) protects nucleus pulposus cells against the inflammatory and oxidative stress-induced degenerative changes

Degeneration of the intervertebral disc is primarily caused by the loss of nucleus pulposus cells (NPCs) and extracellular matrix (ECM) (IDD). Bu-Shen-Huo-Xue-Fang (BSHXF), a traditional Chinese medicine decoction, has been used to treat IDD in clinical; nevertheless, the active components and underlying molecular mechanisms remain unknown. BSHXF improved IL-1β and H2O2 stimulation-induced injuries on NPCs by promoting cell viability, increasing ECM deposition, inhibiting cell senescence, and decreasing the levels of inflammatory factors. The active ingredients in BSHXF were identified by LC-MS/MS analysis; three active ingredients from the principal drugs, Aucubin, Tanshinol, and Tanshinone II A promoted NPC viability; and Aucubin and Tanshinol promoted NPC viability more. Aucubin and Tanshinol, respectively, improved H2O2 stimulation-induced injuries on NPCs by promoting cell viability, increasing ECM deposition, inhibiting cell senescence, and decreasing the levels of inflammatory factors. The activator of NF-κB and Wnt signaling pathways attenuated Aucubin and Tanshinol's protective effects by promoting ECM degradation and NPC senescence. Aucubin, Tanshinol, and Tanshinone II A were identified as the most potent compounds in BSHXF protection against degenerative changes in NPCs. The NF-κB and Wnt signaling pathways might be involved in the protective effects of Aucubin and Tanshinol against H2O2-induced degenerative changes.

Synthetic Calcium-Phosphate Materials for Bone Grafting

Synthetic bone grafting materials play a significant role in various medical applications involving bone regeneration and repair. Their ability to mimic the properties of natural bone and promote the healing process has contributed to their growing relevance. While calcium-phosphates and their composites with various polymers and biopolymers are widely used in clinical and experimental research, the diverse range of available polymer-based materials poses challenges in selecting the most suitable grafts for successful bone repair. This review aims to address the fundamental issues of bone biology and regeneration while providing a clear perspective on the principles guiding the development of synthetic materials. In this study, we delve into the basic principles underlying the creation of synthetic bone composites and explore the mechanisms of formation for biologically important complexes and structures associated with the various constituent parts of these materials. Additionally, we offer comprehensive information on the application of biologically active substances to enhance the properties and bioactivity of synthetic bone grafting materials. By presenting these insights, our review enables a deeper understanding of the regeneration processes facilitated by the application of synthetic bone composites.

Kruppel-like Factors in Skeletal Physiology and Pathologies

Kruppel-like factors (KLFs) belong to a large group of zinc finger-containing transcription factors with amino acid sequences resembling the Drosophila gap gene Krüppel. Since the first report of molecular cloning of the KLF family gene, the number of KLFs has increased rapidly. Currently, 17 murine and human KLFs are known to play crucial roles in the regulation of transcription, cell proliferation, cellular differentiation, stem cell maintenance, and tissue and organ pathogenesis. Recent evidence has shown that many KLF family molecules affect skeletal cells and regulate their differentiation and function. This review summarizes the current understanding of the unique roles of each KLF in skeletal cells during normal development and skeletal pathologies.

Antiosteoporosis effect of tanshinol in osteoporosis animal models: A systematic review and meta-analysis

Background: Osteoporosis (OP) is an age-related bone disease that has emerged as a worldwide public health concern due to its increasing incidence and high disability rate. Tanshinol [D (+) β-3,4-dihydroxyphenyl lactic acid, TS], a water-soluble component extracted from Salvia miltiorrhiza, has proven to be effective in attenuating OP in vitro and in vivo. However, there is insufficient evidence to support its clinical application.

Objective: This meta-analysis aimed to investigate available OP animal model studies to demonstrate the antiosteoporosis effects of TS in a systematic manner.

Methods: Electronic searches of related studies were conducted in the following databases: EMBASE, PubMed, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, Chinese VIP Database, Chinese Biomedical Literature Database, and Wanfang. The retrieval date was January 2022, and there were no time or language restrictions. The CAMARADES 10-item quality checklist was utilized to test the risk of potential bias for each study, and modifications were performed accordingly. The primary outcome was bone mineral density (BMD, which included the femur and lumbar spine); and secondary outcomes were parameters for trabecular bone such as bone volume over total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), conditions of the femur (including bone maximum load and bone elastic load), and markers of bone metabolism (serum osteocalcin, S-OCN).

Results: A total of nine studies including 176 rats were chosen for this analysis. Egger’s test revealed the presence of publication bias in various studies regarding the primary outcome. According to this systematic review, TS significantly increased the BMD of the femur (BMD-femur) (SMD = 4.40; 95% CI = 1.61 to 7.19; p = 0.002, I² = 94.6%), BMD of the lumbar spine (BMD-lumbar) (SMD = 6.390; 95% CI = 2.036 to 10.744; p = 0.004, I² = 95.9%), BV/TV (SMD = 0.790; 95% CI = 0.376 to 1.204; p = 0.000, I² = 10.8), Tb.N (SMD = 0.690; 95% CI = 0.309 to 1.071; p = 0.000, I² = 12%), Tb.Th (SMD = 0.772; 95% CI = 0.410 to 1.134; p = 0.000, I² = 32.2%), and S-OCN (SMD = 3.13; 95% CI = 0.617 to 5.65; p = 0.015, I² = 92.3%), while the Tb.Sp level was markedly decreased in OP models in comparison to the controls (SMD = −0.822; 95% CI = −1.207 to −0.437; p = 0.000, I² = 0%). Moreover, TS treatment was associated with a significant improvement of the bone biomechanical indicators, including bone maximum load (SMD = 0.912; 95% CI = 0.370 to 1.455; p = 0.001, I² = 40%) and elasticity load (SMD = 0.821; 95% CI = 0.290 to 1.351; p = 0.002, I² = 0%).

Conclusion: Collectively, our findings suggest that TS can improve BMD, bone microarchitecture, bone biomechanics, and S-OCN expression in rats, implying that it could be used clinically in the future.

Systematic Review Registration:https://inplasy.com/inplasy-2022-3-0053/, identifier [INPLASY202230053].

Improving the valence self-reversible conversion of cerium nanoparticles on titanium implants by lanthanum doping to enhance ROS elimination and osteogenesis

Equipped with anti-oxidative properties, cerium oxide nanoparticles (CNPs) are gradually being adopted over the years in the field of oxidative stress research. However, the effects of CNPs may be diminished when under the influence of prolonged and substantially elevated levels of oxidative stress. Therefore, it is imperative to enhance the efficacy of CNPs to resist oxidative stress. In this study, our approach involves the fabrication of titanium surface CNPs coatings doped with different concentrations of lanthanum ions (La³⁺) and the investigation of their local anti-oxidative stress potential. The physicochemical characterization showed that the La-CNPs groups had a substantial increase in the generation of oxygen vacancies within the CNPs structure with the increase of La doping concentration. In vitro findings proofed that the cytocompatibility of different La-CNPs coatings showed a trend of increasing first and then decreasing with the increase of La doping concentration under oxidative stress microenvironment. Among these groups, the 30 % La-CNPs group presented the best cell proliferation and osteogenic differentiation which could activate the FoxO1 pathway, then upregulated the expression of SOD1 and CAT, and finally resulted in the inhibition of ROS production. In vivo results further confirmed that the 30 % La-CNPs group showed significant osteogenic effects in two rat models (osteoporosis and diabetes models). In conclusion, we believe that the 30 % La-CNPs coating holds promising potential for its implant applications in patients with oxidative stress-related diseases.

Animal Model for Glucocorticoid Induced Osteoporosis: A Systematic Review from 2011 to 2021

Clinical and experimental data have shown that prolonged exposure to GCs leads to bone loss and increases fracture risk. Special attention has been given to existing emerging drugs that can prevent and treat glucocorticoid-induced osteoporosis GIOP. However, there is no consensus about the most relevant animal model treatments on GIOP. In this systematic review, we aimed to examine animal models of GIOP centering on study design, drug dose, timing and size of the experimental groups, allocation concealment, and outcome measures. The present review was written according to the PRISMA 2020 statement. Literature searches were performed in the PubMed electronic database via Mesh with the publication date set between April, 2011, and February 2021. A total of 284 full-text articles were screened and 53 were analyzed. The most common animal species used to model GIOP were rats (66%) and mice (32%). In mice studies, males (58%) were preferred and genetically modified animals accounted for 28%. Our work calls for a standardization of the establishment of the GIOP animal model with better precision for model selection. A described reporting design, conduction, and selection of outcome measures are recommended.

Salvianolate Ameliorates Osteopenia and Improves Bone Quality in Prednisone-Treated Rheumatoid Arthritis Rats by Regulating RANKL/RANK/OPG Signaling

Rheumatoid arthritis (RA) is closely associated with periarticular osteopenia and leads to a high risk of generalized osteoporosis. Although glucocorticoid (GC) treatment ameliorates joint degradation and manages inflammation in RA, GC application may induce further bone quality deterioration in RA patients. Current treatments for RA lack relevant strategies for the prevention and treatment of osteopenia in RA. In this study, we aimed to investigate whether salvianolate treatment ameliorated osteopenia in prednisone-treated RA rats. Lewis rats with collagen-induced arthritis (CIA) were administered prednisone (PDN) or PDN plus salvianolate (PDN+Sal) treatment for 90 days. The effects of Sal were investigated in PDN-treated CIA rats. To further evaluate the effects of Sal under inflammatory conditions, we investigated the effects of Sal treatment on the TNF-α-induced inflammatory response in MC3T3-E1 osteoblasts. Bone histomorphometry, bone mineral density (BMD), bone biomechanical properties, micro-computed tomography (micro-CT), immunohistochemistry, RT-PCR and western blot analyses were performed to evaluate the effects of Sal. The results demonstrated that RA induced bone loss and bone quality deterioration, with high bone turnover in CIA rats. PDN+Sal treatment significantly increased BMD and trabecular/cortical bone mass, suppressed inflammation, and improved bone biomechanical properties compared to CIA control and PDN treatment. PDN+Sal treatment significantly suppressed bone resorption and the RANKL and RANKL/OPG ratios compared to PDN. PDN+Sal and PDN treatment significantly inhibited TNF-α by 82 and 83%, respectively, and both suppressed inflammation in CIA rats. However, there was no significant difference between PDN+Sal and PDN treatment alone in regard to bone formation parameters or the management of inflammation and arthropathy. Sal significantly increased Osterix, OPN, and Col1a1 while decreasing RANKL, TRAF6, and TRAIL gene in TNF-α-induced MC3T3-E1 osteoblasts. Sal significantly increased Osterix, OPN and RUNX2 while decreasing NF-κB, TRAF6 and IL-1β protein in TNF-α-induced MC3T3-E1 osteoblasts. The results suggested that salvianolate treatment ameliorated osteopenia and improved bone quality in prednisone-treated RA rats, and the potential mechanism may be related to the regulation of the RANKL/RANK/OPG signaling pathway, TRAIL-TRAF6-NFκB signal axis, and downregulation of inflammatory cytokines. Salvianolate could be used as a promising supplemental therapeutic strategy to ameliorate osteopenia and improve bone quality in GC-treated RA patients.

Tanshinol Alleviates Microcirculation Disturbance and Impaired Bone Formation by Attenuating TXNIP Signaling in GIO Rats

Impaired bone formation is the main characteristics of glucocorticoid (GC)-induced osteoporosis (GIO), which can be ameliorated by tanshinol, an aqueous polyphenol isolated from Salvia miltiorrhiza Bunge. However, the underlying mechanism is still not entirely clear. In the present study, we determined the parameters related to microstructure and function of bone tissue, bone microcirculation, and TXNIP signaling to investigate the beneficial effects of tanshinol on skeleton and its molecular mechanism in GIO rats. Male Sprague-Dawley rats aged 4 months were administrated orally with distilled water (Con), tanshinol (Tan, 25 mg kg-1 d-1), prednisone (GC, 5 mg kg-1 d-1) and GC plus tanshinol (GC + Tan) for 14 weeks. The results demonstrated that tanshinol played a significant preventive role in bone loss, impaired microstructure, dysfunction of bone metabolism and poor bone quality, based on analysis of correlative parameters acquired from the measurement by using Micro-CT, histomorphometry, ELISA and biomechanical assay. Tanshinol also showed a significant protective effect in bone microcirculation according to the evidence of microvascular perfusion imaging of cancellous bone in GIO rats, as well as the migration ability of human endothelial cells (EA.hy926, EA cells). Moreover, tanshinol also attenuated GC-elicited the activation of TXNIP signaling pathway, and simultaneously reversed the down-regulation of Wnt and VEGF pathway as manifested by using Western-blot method in GIO rats, EA cells, and human osteoblast-like MG63 cells (MG cells). Collectively, our data highlighted that tanshinol ameliorated poor bone health mediated by activation of TXNIP signaling via inhibiting microcirculation disturbance and the following impaired bone formation in GIO rats.

Oxidative Stress-Induced Hypermethylation of KLF5 Promoter Mediated by DNMT3B Impairs Osteogenesis by Diminishing the Interaction with β-Catenin

Aims: Emerging evidence suggests that the pathogenesis of osteoporosis, characterized by impaired osteogenesis, is shifting from estrogen centric to oxidative stress. Our previous studies have shown that the zinc-finger transcription factor krüppel-like factor 5 (KLF5) plays a key role in the degeneration of nucleus pulposus and cartilage. However, its role in osteoporosis remains unknown. We aimed to investigate the effect and mechanism of KLF5 on osteogenesis under oxidative stress. Results: First, KLF5 was required for osteogenesis and stimulated osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). KLF5 was hypermethylated and downregulated in ovariectomy-induced osteoporosis mice and in BMSCs treated with H2O2. Interestingly, DNA methyltransferases 3B (DNMT3B) upregulation mediated the hypermethylation of KLF5 induced by oxidative stress, thereby impairing osteogenic differentiation. The inhibition of KLF5 hypermethylation using DNMT3B siRNA or 5-AZA-2-deoxycytidine (5-AZA) protected osteogenic differentiation of BMSCs from oxidative stress. Regarding the downstream mechanism, KLF5 induced β-catenin expression. More importantly, KLF5 promoted the nuclear translocation of β-catenin, which was mediated by the armadillo repeat region of β-catenin. Consistently, oxidative stress-induced KLF5 hypermethylation inhibited osteogenic differentiation by reducing the expression and nuclear translocation of β-catenin. Innovation: We describe the novel effect and mechanism of KLF5 on osteogenesis under oxidative stress, which is linked to osteoporosis for the first time. Conclusion: Our results suggested that oxidative stress-induced hypermethylation of KLF5 mediated by DNMT3B impairs osteogenesis by diminishing the interaction with β-catenin, which is likely to contribute to osteoporosis. Targeting the hypermethylation of KLF5 might be a new strategy for the treatment of osteoporosis. Antioxid. Redox Signal. 35, 1-20.

Tanshinol alleviates ulcerative colitis by promoting the expression of VLDLR

Tanshinol (TAN) is a widely used Chinese medicine ingredient with anti‐inflammatory activity. The therapeutic effect of TAN in ulcerative colitis (UC) deserves further investigation. DSS induced UC model for mice, and TAN of different concentrations was used for in vivo therapy. Colons length was measured; expression of VLDLR in colonic mucosal tissue was evaluated by qRT‐PCR, Western blot and histochemical staining. Besides, normal colorectal mucosal cell line (FHC) was treated with LPS to imitate the inflammatory process of UC in vitro. Different concentrations of TAN treated UC cell model. ELISA and qRT‐PCR were applied to examine the concentrations of inflammatory cytokines (TNF‐α, IL‐6, IL‐8, or IL‐1β). Flow cytometry and MTT was used to identify the apoptosis and viability of FHC cells, respectively. Afterwards, Western blot was performed to detect the expressions of Bax, Bcl‐2, Cleaved caspase‐3, and Cleaved caspase‐9 in FHC cells. VLDLR was low‐expressed in UC tissues as compared to the normal tissue. TAN could alleviate DSS‐induced colons length shortening, colonic tissue structure destruction, inflammatory response, and VLDLR expression decrease in vivo. Further study found that TAN could alleviate LPS‐induced inflammatory response, apoptosis, and viability decrease of FHC cells, and siVLDLR could partially offset the effect of TAN. TAN alleviates LPS‐induced viability decrease, apoptosis, and inflammatory response in FHC cells by promoting VLDLR expression.

Allicin Reversed the Process of Frailty in Aging Male Fischer 344 Rats With Osteoporosis

The research and development of pharmaceutical intervention is insufficient for the frail older adults, especially in preclinical stage for the frail individuals with osteoporosis. Garlic exerts an antiosteoporotic effect and its vital component allicin could protect organisms against aging. The present study aimed to investigate the effect of long-term intragastric administration of allicin (low dose of 4 mg·kg⁻¹·d⁻¹; middle dose of 8 mg·kg⁻¹·d⁻¹; high dose of 16 mg·kg⁻¹·d⁻¹) on frailty with osteoporosis in aging male Fischer 344 rats. Frailty was assessed with a 27-item frailty index based on quantifying health-related deficits in adult male rats varied from 13 to 21 months and in control rats from 6 to 9 months. Osteoporosis was appraised by bone mineral density detected by dual-energy X-ray absorptiometry, biomechanical properties measured by a three-point bending test, and bone metabolic analysis using ELISA. Allicin could attenuate frailty index scores by reducing the accumulation of health deficits in aging male Fischer 344 rats. Meanwhile, allicin could protect against senile osteoporosis, and the underlying mechanism may involve in increasing low bone turnover through elevation of both bone formation and bone resorption, and subsequently lead to increase of bone mineral density, contributing to reversing deleterious bone biomechanical features associated with aging. The present study reveals firstly that long-term oral administration with allicin attenuated frailty with osteoporosis during the process of aging, which provides a preclinical evidence for intervention of frailty.

Bone-Targeting Liposome-Encapsulated Salvianic Acid A Improves Nonunion Healing Through the Regulation of HDAC3-Mediated Endochondral Ossification

AIM

Nonunion is a major complication in fracture repair and remains a challenge in orthopaedics and trauma surgery. In this study, we aimed to evaluate the effectiveness of treatment of nonunion with a large radial defect using a bone-targeting liposome-encapsulated salvianic acid A (SAA-BTL)-incorporated collagen sponge and further elucidate whether the effects were closely related to histone deacetylase 3 (HDAC 3)-mediated endochondral ossification in nonunion healing process.

METHODS

Fifteen New Zealand female rabbits were randomly divided into three groups. Segmental radius critical size defects (15 mm) were created via surgery on both the forelimbs of the rabbits. The SAA-BTL/SAA/saline-incorporated collagen sponges were implanted into the defects in the three groups, respectively, for four weeks of treatment. X-ray imaging, micro-computed tomography (CT) analysis, histology, and immunofluorescence analysis (HDAC3, collagen II, VEGFA, and osteocalcin) were performed to determine the effects of the treatments. In addition, a short interfering RNA was applied to induce HDAC3 knockdown in the chondrogenic cell line ATDC5 to investigate the roles of HDAC3 and SAA intervention in endochondral ossification in nonunion healing.

RESULTS

X-ray imaging and micro-CT results revealed that SAA-BTL-incorporated collagen sponges significantly stimulated bone formation in the nonunion defect rabbit model. Furthermore, immunofluorescence double staining and histology analysis confirmed that SAA-BTL significantly increased the expression of P-HDAC3, collagen II, RUNX2, VEGFA, and osteocalcin in vivo; accelerated endochondral ossification turnover from cartilage to bone; and promoted long bone healing of nonunion defects. ATDC5 cells knocked down for HDAC3 showed significantly decreased expression of HDAC3, which resulted in reduced expression of chondrogenesis, osteogenesis, and angiogenesis biomarker genes (Sox9, Col10a1, VEGFA, RUNX2, and Col1a1), and increased expression of extracellular matrix degradation marker (MMP13). SAA treatment reversed these effects in the HDAC3 knockdown cell model.

CONCLUSION

SAA-BTL can improve nonunion healing through the regulation of HDAC3-mediated endochondral ossification.

Cycloastragenol prevents age-related bone loss: Evidence in d-galactose-treated and aged rats

BACKGROUND AND AIMS

Aging-induced bone loss is a multifactorial, age-related, and progressive phenomenon among the general population and may further progress to osteoporosis and increase the risk of fractures. Cycloastragenol (CAG), currently the only compound reported that activates human telomerase, is thought to be able to alleviate or delay the symptoms of aging and chronic diseases. Previous research has suggested that CAG may have the potential to alleviate age-related bone loss. However, to date, no research has specifically focused on this aspect. In this study, we aimed to investigate whether CAG could prevent senile osteoporosis, and further reveal its underlying mechanism.

METHODS

CAG treatment was administrated into two bone loss rat models (D-galactose administration and aging) for 20 weeks and 33 weeks, respectively. Serum biomarkers analyses, bone biomechanical tests, micro-computed tomography assessment, and bone histomorphometry analyses were performed on the bone samples collected at the endpoint, to determine whether CAG could prevent or alleviate age-related bone loss. Proteomic analysis was performed to reveal the changes in protein profiles of the bones, and western blot was used to further verify the identity of the key proteins. The viability, osteoblastic differentiation, and mineralization of MC3T3-E1 cells were also evaluated after CAG treatment in vitro.

RESULTS

The results suggest that CAG treatment improves bone formation, reduces osteoclast number, alleviates the degradation of bone microstructure, and enhances bone biomechanical properties in both d-galactose- and aging-induced bone loss models. CAG treatment promotes viability, osteoblastic differentiation, and mineralization in MC3T3-E1 cells. Proteomic and western blot analyses revealed that CAG treatment increases osteoactivin (OA) expression to alleviate bone loss.

CONCLUSION

The results revealed that CAG alleviates age-related bone loss and improves bone microstructure and biomechanical properties. This may due to CAG-induced increase in OA expression. In addition, the results support preclinical investigations of CAG as a potential therapeutic medicine for the treatment of senile osteoporosis.

Transcriptional Regulation of Osteoclastogenesis: The Emerging Role of KLF2

Dysregulation of osteoclastic differentiation and its activity is a hallmark of various musculoskeletal disease states. In this review, the complex molecular factors underlying osteoclastic differentiation and function are evaluated. The emerging role of KLF2 in regulation of osteoclastic differentiation is examined, specifically in the context of rheumatoid arthritis in which it has been most extensively studied among the musculoskeletal diseases. The therapies that exist to manage diseases associated with osteoclastogenesis are numerous and diverse. They are varied in their mechanisms of action and in the outcomes they produce. For this review, therapies targeting osteoclasts will be emphasized, though it should be noted that many therapies exist which bolster the action of osteoblasts. A new targeted molecular approach is under investigation for the future potential therapeutic development of rheumatoid arthritis.

Bone-targeting liposome formulation of Salvianic acid A accelerates the healing of delayed fracture Union in Mice

Delayed fracture union is a significant clinical challenge in orthopedic practice. There are few non-surgical therapeutic options for this pathology. To address this challenge, we have developed a bone-targeting liposome (BTL) formulation of salvianic acid A (SAA), a potent bone anabolic agent, for improved treatment of delayed fracture union. Using pyrophosphorylated cholesterol as the targeting ligand, the liposome formulation (SAA-BTL) has demonstrated strong affinity to hydroxyapatite in vitro, and to bones in vivo. Locally administered SAA-BTL was found to significantly improve fracture callus formation and micro-architecture with accelerated mineralization rate in callus when compared to the dose equivalent SAA, non-targeting SAA liposome (SAA-NTL) or no treatment on a prednisone-induced delayed fracture union mouse model. Biomechanical analyses further validated the potent therapeutic efficacy of SAA-BTL. These results support SAA-BTL formulation, as a promising therapeutic candidate, to be further developed into an effective and safe clinical treatment for delayed bone fracture union.

Tanshinol alleviates impaired bone formation by inhibiting adipogenesis via KLF15/PPARγ2 signaling in GIO rats

Glucocorticoid (GC)-induced osteoporosis (GIO) is characterized by impaired bone formation, which can be alleviated by tanshinol, an aqueous polyphenol isolated from Salvia miltiorrhiza Bunge. In this study we investigated the molecular mechanisms underlying GC-induced modulation of osteogenesis as well as the possibility of using tanshinol to interfere with GIO. Female SD rats aged 4 months were orally administered distilled water (Con), prednisone (GC, 5 mg·kg-1·d-1), GC plus tanshinol (Tan, 16 mg·kg-1·d-1) or GC plus resveratrol (Res, 5 mg·kg-1·d-1) for 14 weeks. After the rats were sacrificed, samples of bone tissues were collected. The changes in bone formation were assessed using Micro-CT, histomorphometry, and biomechanical assays. Expression of Kruppel-like factor 15 (KLF15), peroxisome proliferator-activated receptor γ 2 (PPARγ 2) and other signaling proteins in skeletal tissue was measured with Western blotting and quantitative RT-PCR. GC treatment markedly increased the expression of KLF15, PPARγ2, C/EBPα and aP2, which were related to adipogenesis, upregulated FoxO3a pathway proteins (FoxO3a and Gadd45a), and suppressed the canonical Wnt signaling (β-catenin and Axin2), which was required for osteogenesis. Thus, GC significantly decreased bone mass and bone quality. Co-treatment with Tan or Res effectively counteracted GC-impaired bone formation, suppressed GC-induced adipogenesis, and restored abnormal expression of the signaling molecules in GIO rats. We conclude that tanshinol counteracts GC-decreased bone formation by inhibiting marrow adiposity via the KLF15/PPARγ2/FoxO3a/Wnt pathway.

Polygonum multiflorm alleviates glucocorticoid‑induced osteoporosis and Wnt signaling pathway

It is known that long-term excessive administration of glucocorticoid (GC) results in osteoporosis. The present study aimed to evaluate the protective effects of Polygonum multiflorm (PM) on the bone tissue of rats with GC-induced osteoporosis (GIO). A total of 90 6-month-old female Sprague Dawley rats (weight range, 190–210 g) were randomly divided into nine groups: Control (normal saline); prednisone (GC; 6 mg·kg⁻¹·d⁻¹; Model); GC plus PMR30 (the 30% ethanol eluent fraction of PM) (H) (400 mg·kg⁻¹·d⁻¹); GC plus PMR30 (M) (200 mg·kg⁻¹·d⁻¹); GC plus PMR30 (L) (100 mg·kg⁻¹·d⁻¹); GC plus PMRF (fat-soluble fraction of PM) (H) (400 mg·kg⁻¹·d⁻¹); GC plus PMRF (M) (200 mg·kg⁻¹·d⁻¹); GC plus PMRF (L) (100 mg·kg⁻¹·d⁻¹); GC plus calcitriol (CAL; 0.045 µg·kg⁻¹·d⁻¹; positive). Rats were administered intragastrically with prednisone and/or the aforementioned extracts for 120 days, and weighed once/week. The serum was collected for detection of biochemical markers. The left tibia was used for bone histomorphometry analysis. The right tibia was prepared for hematoxylin and eosin staining. The left femur was used to analyze the protein expression of dickkopf-1 (DKK1), WNT inhibitory factor 1 (WIF1) and secreted frizzled related protein 4 using western blotting. Long-term excessive treatment of prednisone inhibited the bone formation rate accompanied with a decrease in bone mass, growth plate, body weight, and the level of bone-specific alkaline phosphatase and hydroxyl-terminal propeptide of type I procollagen in the serum. Furthermore, a simultaneously increase in the level of tartrate resistant acid phosphatase-5b and cross-linked carboxy-terminal telopeptide of type I collagen in the serum, in addition to DKK1, and WIF1 protein expression, was observed. PMR30 (M and L) and PMRF (H) groups were able to reduce the negative effects of GC on the bones. PMR30 (M and L) and PMRF (H) dose demonstrated a protective effect of PM on bone tissue in GIO rats. The mechanism underlying the preventive effect of PM for the treatment of GIO may be associated with direct upregulation of the canonical Wnt/β-catenin signaling pathway.

Effects of tanshinol on markers of bone turnover in ovariectomized rats and osteoblast cultures

This study was aimed to explore the role of tanshinol in osteoblastic cells, and the role in vivo using an ovariectomized (OVX) rat model of osteoporosis. MC3T3-E1 cells were pretreated with 0–400 μg/mL tanshinol, and then cell viability, apoptosis, alkaline phosphatase (ALP) activity and the expressions of Collagen Type I Alpha 1 (Col1A1), Runt Related Transcription Factor 2 (Runx2) and osteocalcin (OCN) were respectively detected. Rats underwent OVX surgery was intervened with 5 mg/kg tanshinol or 25 μg/kg β-estradiol (E2) for 12 weeks. The triglycerides (TG), total cholesterol (TC), high and low density lipoprotein cholesterol (HDL-C and LDL-C), ALP, OCN and Tartrate-resistant acid phosphatase-5b (TRACP-5b) contents were measured. Besides, the expressions of main factors in nuclear factor-kappa B (NF-κB) pathway were detected. The results showed that tanshinol significantly promoted MC3T3-E1 cells viability and ALP activity, while inhibited apoptosis (P < 0.05); Col1A1, Runx2 and OCN were all up-regulated by tanshinol (P < 0.05). In OVX rats, the contents of TG, TC, LDL-C, ALP, OCN and TRACP-5b were all increased (P < 0.05), while HDL-C was decreased (P < 0.05). Tanshinol significantly alleviated these aberrant regulations (P < 0.05). Inhibitory subunit of NF-κB (IκBα) and p65 were both remarkably phosphorylated by OVX, while this phosphorylation was partially neutralized by tanshinol (P < 0.05). In conclusion, we demonstrated that tanshinol exerted a bone-protective function by modulating the markers of bone turnover possibly via blocking NF-κB pathway. This study will provide new evidence that tanshinol is a potential therapeutic option for the relief of estrogen deficiency-induced osteoporosis.

Pharmacokinetic study of representative anti-oxidative compounds from Denshen-Chuanxiong-Honghua following oral administration in rats

Almost no pharmacokinetic compounds to date have been precisely linked with the activity of their herbal or Traditional Chinese Medicine (TCM) formula. This creates challenges for pharmacokinetic significance and application of the TCM. In our study, a sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to quantitatively or qualitatively determine multiple-components (tanshinol, ferulic acid, protocatechuic acid, rosmarinic acid, salvianolic acid B, baicalin and 9'-methyl lithospermate B) in rat plasma following the oral administration of Denshen-Chuanxiong-Honghua (DCH) extract (20g/kg). Chromatographic separation was carried out on a 300SB-C18 column using a gradient elution with a mobile phase composed of acetonitrile-water (containing 0.1% formic acid) at a flow rate of 1.0mL/min. Determination by mass spectrometry (MS) was conducted in multiple reaction monitoring (MRM) mode with negative electrospray ionization. The validated method exhibited good linearity, with correlation coefficients greater than 0.9949 over a wide concentration range, and the lower limits of quantification were 2.09-12.2ng/mL for the 5 analytes. This assay was successfully applied to investigate the pharmacokinetics of 5 compounds in rat plasma after the oral administration of DCH extracts. In addition, the anti-oxidant capacities of the 5 active ingredients of DCH extract in vitro and the total absorbed DCH extract in vivo were investigated at different concentrations during pharmacokinetic studies.