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

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.

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.

In Vitro and In Vivo Bone-Forming Effect of a Low-Molecular-Weight Collagen Peptide

This study reveals that low-molecular-weight collagen peptide (LMWCP) can stimulate the differentiation and the mineralization of MC3T3-E1 cells in vitro and attenuate the bone remodeling process in ovariectomized (OVX) Sprague-Dawley rats in vivo. Moreover, the assessed LMWCP increased the activity of alkaline phosphatase (ALP), synthesis of collagen, and mineralization in MC3T3-E1 cells. Additionally, mRNA levels of bone metabolism-related factors such as the collagen type I alpha 1 chain, osteocalcin (OCN), osterix, bone sialoprotein, and the Runt family-associated transcription factor 2 were increased in cells treated with 1,000 μg/ml of LMWCP. Furthermore, we demonstrated that critical bone morphometric parameters exhibited significant differences between the LMWCP (400 mg/kg)-receiving and vehicle-treated rat groups. Moreover, the expression of type I collagen and the activity of ALP were found to be higher in both the femur and lumbar vertebrae of OVX rats treated with LMWCP. Finally, the administration of LMWCP managed to alleviate osteogenic parameters such as the ALP activity and the levels of the bone alkaline phosphatase, the OCN, and the procollagen type 1 N-terminal propeptide in OVX rats. Thus, our findings suggest that LMWCP is a promising candidate for the development of food-based prevention strategies against osteoporosis.

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.

Curcumin Prevents Diabetic Osteoporosis through Promoting Osteogenesis and Angiogenesis Coupling via NF-κB Signaling

Diabetic osteoporosis (DOP) is a metabolic disease which is characterized by impaired bone microarchitecture and reduced bone mineral density resulting from hyperglycemia. Curcumin, an effective component extracted from Curcuma longa, exhibits antioxidation, regulation of bone metabolism and hypoglycemic effects. The BMSC-mediated osteogenesis and angiogenesis coupling seems to be important in bone formation and regeneration. We aimed to explore the effect of curcumin on BMSC-mediated osteogenesis-angiogenesis coupling in high glucose conditions and underlying mechanisms. Our results showed that high glucose impaired the osteogenic and proangiogenic ability of BMSCs and that curcumin pretreatment rescued the BMSC dysfunction induced by high-concentration glucose. Inhibition of the high glucose-activated NF-κB signaling pathway has been found to contribute to the protective effects of curcumin on high glucose-inhibited coupling of osteogenesis and angiogenesis in BMSCs. Furthermore, accelerated bone loss and decreased type H vessels were observed in diabetic osteoporosis mice models. However, curcumin treatment prevented bone loss and promoted vessel formation in diabetic osteoporosis mice. Based on these results, we concluded that curcumin ameliorated diabetic osteoporosis by recovering the osteogenesis and angiogenesis coupling of BMSCs in hyperglycemia, partly through inhibiting the high glucose-activated NF-κB signaling pathway.

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].

PTHrP promotes subchondral bone formation in TMJ-OA

PTH-related peptide (PTHrP) improves the bone marrow micro-environment to activate the bone-remodelling, but the coordinated regulation of PTHrP and transforming growth factor-β (TGFβ) signalling in TMJ-OA remains incompletely understood. We used disordered occlusion to establish model animals that recapitulate the ordinary clinical aetiology of TMJ-OA. Immunohistochemical and histological analyses revealed condylar fibrocartilage degeneration in model animals following disordered occlusion. TMJ-OA model animals administered intermittent PTHrP (iPTH) exhibited significantly decreased condylar cartilage degeneration. Micro-CT, histomorphometry, and Western Blot analyses disclosed that iPTH promoted subchondral bone formation in the TMJ-OA model animals. In addition, iPTH increased the number of osterix (OSX)-positive cells and osteocalcin (OCN)-positive cells in the subchondral bone marrow cavity. However, the number of osteoclasts was also increased by iPTH, indicating that subchondral bone volume increase was mainly due to the iPTH-mediated increase in the bone-formation ability of condylar subchondral bone. In vitro, PTHrP treatment increased condylar subchondral bone marrow-derived mesenchymal stem cell (SMSC) osteoblastic differentiation potential and upregulated the gene and protein expression of key regulators of osteogenesis. Furthermore, we found that PTHrP-PTH1R signalling inhibits TGFβ signalling during osteoblastic differentiation. Collectively, these data suggested that iPTH improves OA lesions by enhancing osteoblastic differentiation in subchondral bone and suppressing aberrant active TGFβ signalling. These findings indicated that PTHrP, which targets the TGFβ signalling pathway, may be an effective biological reagent to prevent and treat TMJ-OA in the clinic.

Serum biomarker-based osteoporosis risk prediction and the systemic effects of Trifolium pratense ethanolic extract in a postmenopausal model

Background

Recent years, a soaring number of marketed Trifolium pratense (red clover) extract products have denoted that a rising number of consumers are turning to natural alternatives to manage postmenopausal symptoms. T. pratense ethanolic extract (TPEE) showed immense potential for their uses in the treatment of menopause complications including osteoporosis and hormone dependent diseases. Early diagnosis of osteoporosis can increase the chance of efficient treatment and reduce fracture risks. Currently, the most common diagnosis of osteoporosis is performed by using dual-energy x-ray absorptiometry (DXA). However, the major limitation of DXA is that it is inaccessible and expensive in rural areas to be used for primary care inspection. Hence, serum biomarkers can serve as a meaningful and accessible data for osteoporosis diagnosis.

Methods

The present study systematically elucidated the anti-osteoporosis and estrogenic activities of TPEE in ovariectomized (OVX) rats by evaluating the bone microstructure, uterus index, serum and bone biomarkers, and osteoblastic and osteoclastic gene expression. Leverage on a pool of serum biomarkers obtained from this study, recursive feature elimination with a cross-validation method (RFECV) was used to select useful biomarkers for osteoporosis prediction. Then, using the key features extracted, we employed five classification algorithms: extreme gradient boosting (XGBoost), random forest, support vector machine, artificial neural network, and decision tree to predict the bone quality in terms of T-score.

Results

TPEE treatments down-regulated nuclear factor kappa-B ligand, alkaline phosphatase, and up-regulated estrogen receptor β gene expression. Additionally, reduced serum C-terminal telopeptides of type 1 collagen level and improvement in the estrogen dependent characteristics of the uterus on the lining of the lumen were observed in the TPEE intervention group. Among the tested classifiers, XGBoost stood out as the best performing classification model with the highest F1-score and lowest standard deviation.

Conclusions

The present study demonstrates that TPEE treatment showed therapeutic benefits in the prevention of osteoporosis at the transcriptional level and maintained the estrogen dependent characteristics of the uterus. Our study revealed that, in the case of limited number of features, RFECV paired with XGBoost model could serve as a powerful tool to readily evaluate and diagnose postmenopausal osteoporosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00622-7.

The cross-talk between matrix metalloproteinase-9, RANKL/OPG system and cardiovascular risk factors in ovariectomized rat model of postmenopausal osteoporosis

Epidemiology and pathogenesis of cardiovascular diseases (CVD) and osteoporosis are strikingly overlapping. This study presents matrix metalloproteinase-9 (MMP-9), as a simple molecular link more consistently associated with the pathophysiology of both osteoporosis and CVD risk factors. 40 adult female rats were randomly distributed into 4 groups [control sham-operated, untreated osteoporosis, carvedilol-treated osteoporosis and alendronate-treated osteoporosis]. After 8 weeks, blood samples were collected to estimate Lipid profile (Total cholesterol, HDL, Triglycerides), inflammatory markers (IL-6, TNF alpha, CRP and NO), and Bone turnover markers (BTM) (Alkaline phosphatase, osteocalcin and pyridinoline). The tibias were dissected to estimate MMP-9 and NF-kB gene expression, OPG, RANKL levels and for histological examination. Induction of osteoporosis resulted in a significant elevation in BTM, inflammatory markers and dyslipidemia. MMP-9 was significantly elevated and positively correlated with BTM, inflammation and dyslipidemia markers. Carvedilol and alendronate exerted a bone preservative role and attenuated dyslipidaemia and inflammation in accordance with their respective effect on MMP-9.

Ameliorative Effects of Pueraria lobata Extract on Postmenopausal Symptoms through Promoting Estrogenic Activity and Bone Markers in Ovariectomized Rats

Pueraria lobata (Willd.) Ohwi, known as kudzu, is one of the most popular traditional medicines in Asian countries. It has been widely used as a natural alternative to hormone replacement therapy for treating postmenopausal symptoms. This study aimed to investigate the estrogenic effect of P. lobata extract (PE) against postmenopausal osteoporosis in ovariectomized (OVX) rats. OVX rats were treated with PE (25–1600 mg/kg) for 8 weeks. Biochemical parameters, estradiol, and bone turnover markers (e.g., osteocalcin, C-terminal telopeptide fragment of type I collagen, deoxypyridinoline, and pyridinoline) were measured in plasma samples. In addition, estrogen receptor-alpha (ER-α) protein expression and morphology of uterine were evaluated. Long-term treatment with PE did not cause liver damage in OVX rats. PE supplementation reduced body weight gain in obese rats with high lipid accumulation induced by ovariectomy. Furthermore, PE exhibited a protective effect against insulin resistance, hyperlipidemia, and hepatic lipid peroxidation. PE treatment increased uterine weight and thickness of the uterine layers in cases of uterus atrophy due to removal of ovaries. The levels of bone turnover markers, which were significantly increased in OVX rats, were decreased by PE treatment. Western blotting analysis showed that ER-α protein expression was upregulated in PE-treated rats compared with OVX rats. These results suggest that PE could be a promising alternative functional food for improving menopausal symptoms.

Metabolomics and physiological analysis of the effect of calcium supplements on reducing bone loss in ovariectomized rats by increasing estradiol levels

BACKGROUND

Data from the 2010-2012 Chinese National Nutrition and Health Survey showed that the vast majority of postmenopausal women in China had dual deficiencies in calcium and estrogen.

OBJECTIVE

This study aimed to clarify whether calcium supplementation alleviated bone loss caused by calcium restriction combined with estrogen deficiency in rats.

METHODS

Forty-eight female rats aged 9 weeks were assigned to 4 groups and fed a low-calcium diet: sham-operated (SHAM-LC), ovariectomized (OVX-LC), and ovariectomized rats treated with 750 mg/kg (OVX-LC-M) or 2800 mg/kg CaCO3 (OVX-LC-H). CaCO3 or distilled water was administered orally for 13 weeks. Bone mineral density (BMD) and histomorphometry of the femur, serum biochemical parameters, and serum metabolites were analyzed.

RESULTS

The OVX-LC rats showed a significant increase in body weight and serum levels of lipid markers, a significant decrease in serum estradiol, calcium, phosphorus, and 25(OH)D levels, and deterioration of the femur. At 750 mg/kg and 2800 mg/kg, CaCO3 reduced the deterioration of trabecular bone and increased the trabecular area percentage (Tb.Ar %) and BMD of the femur. Serum estradiol levels increased in a dose-dependent manner after CaCO3 supplementation (p < 0.01). The administration of 2800 mg/kg CaCO3 decreased serum triglyceride and high-density lipoprotein levels (p < 0.05) and decreased the levels of the bone turnover markers osteocalcin, N-telopeptide of type I collagen and β-crosslaps. The results of the metabolomics analysis showed that the glycerophospholipid metabolism pathway was closely related to calcium supplementation, and more DG (44:6 n3), LysoPC (22:2) and PE (P-34:3) and less Cer (d43:0) and PE-NMe2 (46:3) were produced.

CONCLUSIONS

The results clearly indicated that calcium supplementation was beneficial for decreasing bone loss in OVX-LC rats. The present study is the first to show that calcium supplementation increased the estradiol content in OVX-LC rats, and the effect of calcium on bone loss may be partially attributed to the increase in the estrogen level that subsequently induced the changes in metabolite levels, eventually increasing the bone mineral density to a relatively higher level to reduce bone deterioration.

Selective activation of the estrogen receptor-β by the polysaccharide from Cynanchum wilfordii alleviates menopausal syndrome in ovariectomized mice

The menopausal syndrome caused by rapid changes in hormone levels greatly influences the quality of life of women. Though hormone replacement therapy (HRT) is widely used to treat the menopausal syndrome, it exhibits many side effects, including the risk of thrombosis, cardiovascular diseases, and increased incidence of breast cancer; thus, diversifying the interest for phytotherapy-based materials as alternatives to HRT. Here, we isolated a crude polysaccharide fraction (CWPF) from Cynanchum wilfordii root that alleviated the ovariectomy-induced uterine atrophy and bone loss without changes in plasma estradiol concentration in mice. Increased plasma levels of follicle-stimulating hormone (FSH), alkaline phosphatase (ALP), osteocalcin (OC) in ovariectomized mice were also reduced to normal levels by CWPF administration. We found that the inhibitory effects of CWPF on menopausal symptoms were mediated by the estrogen receptor β (ER-β) specific activation, not ER-α. Moreover, CWPF treatment suppressed the phosphorylation of Akt, suggesting that CWPF alleviates post-menopausal symptoms by regulating ER-β related Akt signaling pathway. These results demonstrate that the polysaccharides corresponding to CWPF among the water-soluble extracts of CW could be used as a beneficial herbal alternative for the development of therapeutic agents to prevent menopausal syndrome in women.

Impact of Dehydroepiandrosterone (DHEA) on Bone Mineral Density and Bone Mineral Content in a Rat Model of Male Hypogonadism

Objectives: The present study examined the effect DHEA (dehydroepiandrosterone) on bone mineral content (BMC) and bone mineral density (BMD) and biomarkers of bone remodeling in orchidectomized male rats. Material and Methods: A total of 32 male rats were divided equally into four groups (n = 8): (i) control group (C), (ii) control treated with DHEA (Control + DHEA), (iii) orchidectomized (ORCH) group that underwent bilateral orchidectomy and (iv) orchidectomized (ORCH) rats treated with DHEA (ORCH+DHEA). DHEA treatment started 4 weeks after orchidectomy and continued for 12 weeks. After 12 weeks the bone mineral density (BMD) and bone mineral content (BMC) were assayed in the tibia and femur of the right hind limb of each rat. We also measured the serum levels of the bone turnover markers deoxypyridinoline (Dpd), N-telopeptide of type I collagen (NTx), alkaline phosphatase (ALP), tartrate-resistant acid phosphatase 5b (TRAP-5b) and osteocalcin (OC) as well as receptor activator of nuclear factor kappa B (RANK) and osteoprotegerin (OPG). Results: Orchidectomy in rats caused significant reduction in BMD, BMC, serum levels of testosterone, PTH (parathyroid hormone), OPG, OC and ALP with significant rise in serum levels of TRAP-5B, RANK, Dpd and NTx1 (p < 0.05). On the other hand, DHEA therapy for 12 weeks caused significant improvement in all studied parameters except NTx1 (p < 0.05). Conclusions: DHEA corrected hypogonadism-induced osteoporosis in male rats probably via inhibiting osteoclastogenesis, stimulating the activity of osteoblasts and stimulating the secretion of PTH and testosterone.

Anti-Osteoporotic Effects of Antioxidant Peptides PIISVYWK and FSVVPSPK from Mytilus edulis on Ovariectomized Mice

Numerous amounts of evidence suggest that bioactive peptides with diverse physiological activities can be nutraceuticals or potential drug candidates. In this study, blue mussel-derived antioxidant peptides PIISVYWK and FSVVPSPK were subjected to evaluate their osteogenic effect in mouse bone marrow mesenchymal stem cells (mBMMSCs) followed by an in vivo anti-osteoporotic effect. Treatment of PIISVYWK and FSVVPSPK on mBMMSCs stimulated alkaline phosphatase activity and calcification. Western blot results revealed that PIISVYWK and FSVVPSPK increased the expression of bone morphogenetic protein-2/4 (BMP-2/4) followed by upregulating p-Smad1/5, type I collagen, and transcription factors including Runx2 and osterix in mBMMSCs. Two peptides also activated the phosphorylation of MAPKs (p-p38, p-ERK, and p-JNK). Treatment of MAPK inhibitors significantly inhibited the BMP signaling pathway, indicating that PIISVYWK and FSVVPSPK stimulated osteoblast differentiation of mBMMSCs through the MAPK-dependent BMP signaling pathway. The anti-osteoporotic effect of PIISVYWK and FSVVPSPK in ovariectomized (OVX) mice was investigated. Treatment of PIISVYWK and FSVVPSPK for ten weeks showed a notable anti-osteoporotic effect in OVX mice via increasing bone mineral density and other bone parameters compared to OVX mice without peptides. Serum analysis also showed that treatment of PIISVYWK and FSVVPSPK completely reduced osteocalcin and ALP (alkAline phosphatase) activity. Taken together, these results suggest that PIISVYWK and FSVVPSPK could be health-promoting functional food ingredients against osteoporosis.

White Tea Reduced Bone Loss by Suppressing the TRAP/CTX Pathway in Ovariectomy-Induced Osteoporosis Model Rats

Osteoporosis is an important skeletal disease characterized by bone weakness and high risk of fracture in postmenopausal women. Tea consumption is known to play an important role in the prevention or alleviation of osteoporosis. However, the therapeutic effects of aqueous extracts of white tea (WT) have not been evaluated in osteoporosis rat models. The aim of this study was to investigate the potential anti-osteoporotic role of WT in ovariectomized (OVX) rats. WT was given orally at 0.5% w/v doses for 12 weeks in OVX rats. Biochemical parameters in blood samples, bone tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide of type 1 collagen (CTX) and estradiol levels were evaluated. Bone mineral density and bone mineral content values were measured in the left femur. In addition to histopathological examination, osteolcalcin, osteopontin and TUNEL levels were determined. OVX group data demonstrated that bone loss occurred by thinning of the metaphyseal growth plates of the femur. Similarly, the levels of TRAP and CTX, markers of osteoclastic activity, were found to be high concurrently with a decrease in femoral bone mineral density. In addition, increased osteolcalcin and osteopontin levels were present in the metaphyseal growth zones. On the other hand, while TRAP and CTX levels were suppressed in the OVX-WT group, bone mineral content increased. In ad­dition, TUNEL, osteocalcin and osteopontin positivity decreased in the right femoral metaphysis growth zones, proliferating zone and resting zone cells. These results showed that chronic WT consumption has a protective effect by reducing bone resorption in OVX-induced osteoporotic rats.

Axin 1 knockdown inhibits osteoblastic apoptosis induced by Porphyromonas gingivalis lipopolysaccharide

BACKGROUND

Porphyromonas gingivalis (Pg) is one of the pathogenic bacteria that cause periodontal diseases, lipopolysaccharide (LPS) is the key factor that triggers alveolar bone absorption. This study explored the action of Axin 1 on Pg-LPS-induced osteoblasts injury, so as to search a possible treatment for periodontal diseases.

METHODS

Rat osteoblasts were dealt with Pg-LPS and Axin 1 knockdown alone or in combination. The effect of Pg-LPS and Axin 1 on osteoblast viability and apoptosis were detected by Cell Counting Kit-8 and flow cytometry. The expressions of alkaline phosphatase (ALP) and Axin 1 in processed osteoblasts were measured by western blot (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) assays. Furthermore, the role of Axin 1 knockdown in the levels of inflammatory cytokines and apoptosis-related proteins were also determined.

RESULTS

Pg-LPS inhibited the viability of osteoblasts and promote apoptosis with concentration and time dependence. ALP expression in Pg-LPS-treated osteoblasts was reduced, while Axin 1 expression was increased. On the one hand, Axin 1 knockdown reversed the Pg-LPS-induced reduction of cell activity and pro-apoptosis effect. On the other hand, Axin 1 knockdown not only improved the ALP activity of Pg-LPS-treated cells, but also reduced the elevation of inflammatory cytokines (TNF-α, IL-1β and IL-6) caused by Pg-LPS. Moreover, Pg-LPS increased the expressions of cleaved Caspase-3 and Bax, and inhibited Bcl-2 expressed, which was rescued by Axin 1 knockdown.

CONCLUSION

Axin 1 knockdown inhibited Pg-LPS-induced osteoblastic apoptosis by regulating the levels of inflammatory cytokines, which may be helpful for the treatment of periodontal diseases.

Therapeutic effect of localized vibration on alveolar bone of osteoporotic rats

OBJECTIVES

Vibration, in the form of high frequency acceleration (HFA), stimulates alveolar bone formation under physiologic conditions and during healing after dental extractions. It is not known if HFA has an anabolic effect on osteoporotic alveolar bone. Our objective is to determine if HFA has a regenerative effect on osteoporotic alveolar bone.

METHODS AND MATERIALS

Adult female Sprague-Dawley rats were divided into five groups: 1) Ovariectomized Group (OVX), 2) Sham-OVX Group that received surgery without ovariectomy, 3) OVX-HFA Group that was ovariectomized and treated daily with HFA, 4) OVX+Static Force Group that was ovariectomized and received the same force as HFA, but without vibration, and 5) Control Group that did not receive any treatment. All animals were fed a low mineral diet for 3 months. Osteoporosis was confirmed by micro-CT of the fifth lumbar vertebra and femoral head. HFA was applied to the maxillary first molar for 5 minutes/day for 28 and 56 days. Maxillae were collected for micro-CT, histology, fluorescent microscopy, protein and RNA analysis, and three-point bending mechanical testing.

RESULTS

Micro-CT analysis revealed significant alveolar bone osteoporosis in the OVX group. Vibration restored the quality and quantity of alveolar bone to levels similar to the Sham-OVX group. Animals exposed to HFA demonstrated higher osteoblast activity and lower osteoclast activity. Osteogenic transcription factors (RUNX2, Foxo1, Osterix and Wnt signaling factors) were upregulated following vibration, while RANKL/RANK and Sclerostin were downregulated. HFA did not affect serum TRAcP-5b or CTx-1 levels. The osteogenic effect was highest at the point of HFA application and extended along the hemimaxillae this effect did not cross to the contra-lateral side.

CONCLUSIONS

Local application of vibration generated gradients of increased anabolic metabolism and decreased catabolic metabolism in alveolar bone of osteoporotic rats. Our findings suggest that HFA could be a predictable treatment for diminished alveolar bone levels in osteoporosis patients.

Suppression Effect of Astaxanthin on Osteoclast Formation In Vitro and Bone Loss In Vivo

Osteoporosis is characterized by a reduction of the bone mineral density (BMD) and microarchitectural deterioration of the bone, which lead to bone fragility and susceptibility to fracture. Astaxanthin (AST) has a variety of biological activities, such as a protective effect against asthma or neuroinflammation, antioxidant effect, and decrease of the osteoclast number in the right mandibles in the periodontitis model. Although treatment with AST is known to have an effect on inflammation, no studies on the effect of AST exposure on bone loss have been performed. Thus, in the present study, we examined the antiosteoporotic effect of AST on bone mass in ovariectomized (OVX) mice and its possible mechanism of action. The administration of AST (5, 10 mg/kg) for 6 weeks suppressed the enhancement of serum calcium, inorganic phosphorus, alkaline phosphatase, total cholesterol, and tartrate-resistant acid phosphatase (TRAP) activity. The bone mineral density (BMD) and bone microarchitecture of the trabecular bone in the tibia and femur were recovered by AST exposure. Moreover, in the in vitro experiment, we demonstrated that AST inhibits osteoclast formation through the expression of the nuclear factor of activated T cells (NFAT) c1, dendritic cell-specific transmembrane protein (DC-STAMP), TRAP, and cathepsin K without any cytotoxic effects on bone marrow-derived macrophages (BMMs). Therefore, we suggest that AST may have therapeutic potential for the treatment of postmenopausal osteoporosis.