Inhibit Bone Loss Research Articles

Trans-cinnamic aldehyde inhibits Aggregatibacter actinomycetemcomitans-induced inflammation in THP-1-derived macrophages via autophagy activation.

Inflammation is an essential response against bacterial infection as a host defense mechanism, which can lead to tissue damage. Aggregatibacter actinomycetemcomitans (Aa) is major pathogen for aggressive periodontitis characterized by rapid destruction of periodontal tissue surrounding teeth. Trans-cinnamic aldehyde is a key bioactive compound of the cinnamon extracts, which has anti-inflammatory, antioxidant, antipyretic, antimicrobial, and anti-cancer properties. The objective of the present study was to investigate the anti-inflammatory effect of trans-cinnamic aldehyde against Aa infection in human THP-1 derived macrophages and on Aa-induced periodontitis in mice. THP-1 cells were differentiated with phorbol 12-mystristate 13-acetate and were infected with live Aa. Trans-cinnamic aldehyde was pretreated 30 minutes before the bacterial infection. Cytokine production was determined by enzyme-linked immunosorbent assay (ELISA) and protein expressions were detected by Western blot analysis. Autophagosome formation was detected by Cyto-ID. Viable cell count was carried out to determine bacterial adhesion, internalization, and intracellular survival. Experimental periodontitis was induced by inoculating Aa orally to mice, and microcomputed tomography was used to evaluate bone loss. Pretreatment of trans-cinnamic aldehyde significantly inhibited Aa-stimulated release of tumor necrosis factor-α and interleukin (IL)-1β. Pretreatment of trans-cinnamic aldehyde inhibited Aa-induced expression of TLR signaling pathway as well as the phosphorylation of JNK, p38, and nuclear factor (NF)-κB. Also, trans-cinnamic aldehyde treatment downregulated the expression of pro-IL-1β, caspase-1, and inflammasome components. Trans-cinnamic aldehyde treatment significantly decreased intracellular survival of Aa. Moreover, the autophagosome formation and the expressions of autophagy markers including Beclin-1, ATG5, and LC3 were increased. Finally, trans-cinnamic aldehyde significantly inhibited bone loss in Aa-induced mouse periodontitis. Trans-cinnamic aldehyde inhibited Aa-stimulated expression of inflammatory responses and inhibited intracellular bacterial survival via autophagy activation. These results suggest that trans-cinnamic aldehyde may serve as an anti-inflammatory agent for aggressive periodontitis.

Modulating calcium-mediated NFATc1 and mitogen-activated protein kinase deactivation underlies the inhibitory effects of kavain on osteoclastogenesis and bone resorption.

Osteoclasts are responsible for bone resorption during the process of bone remodeling. Increased osteoclast numbers and bone resorption activity are the main factors contributing to bone loss-related diseases such as osteoporosis. Therefore, modulating the formation and function of osteoclasts is critical for the effective treatment of osteolysis and osteoporosis. Kavain is the active ingredient extracted from the root of the kava plant, which possesses known anti-inflammatory properties. However, the effects of kavain on osteoclastogenesis and bone resorption remain unclear. In this study, we found that kavain inhibits receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and fusion using tartrate-resistant acid phosphatase staining and immunofluorescence. Furthermore, kavain inhibited bone resorption performed by osteoclasts. Using reverse transcription-polymerase chain reaction and western blot analysis, we found that kavain downregulates the expression of osteoclast marker genes, such as nuclear factor of activated T cells, cytoplasmic 1 (Nfatc1), v-atpase d2 (Atp6v0d2), dendrocyte expressed seven transmembrane protein (Dcstamp), matrix metallopeptidase 9 (Mmp9), cathepsin K (Ctsk), and Acp5. Additionally, kavain repressed RANKL-induced calcium oscillations, nuclear factor of activated T cells activation, and mitogen-activated protein kinase phosphorylation, while leaving NF-κB unaffected. We found no effects of kavain on either osteoblast proliferation or differentiation. Besides, kavain inhibited bone loss in ovariectomized mice by suppressing osteoclastogenesis. Collectively, these data suggest a potential use for kavain as a candidate drug for the treatment of osteolytic diseases.

Tectorigenin inhibits RANKL-induced osteoclastogenesis via suppression of NF-κB signalling and decreases bone loss in ovariectomized C57BL/6.

Metabolism of bone is regulated by the balance between osteoblast‐mediated bone formation and osteoclast‐mediated bone resorption. Activation of osteoclasts could lead to osteoporosis. Thus, inhibiting the activity of osteoclasts becomes an available strategy for the treatment of osteoporosis. Tectorigenin is an extract of Belamcanda chinensis In the present study, the anti‐osteoclastogenesis effects of tectorigenin were investigated in vitro and in vivo. The results showed preventive and therapeutic effects of tectorigenin at concentrations of 0, 10, 40, and 80 μmol/L in the maturation and activation of osteoclasts. A signalling study also indicated that tectorigenin treatment reduces activation of NF‐κB signalling in osteoclastogenesis. Animal experiment demonstrated that tectorigenin treatment (1‐10 mg/kg, abdominal injection every 3 days) significantly inhibits bone loss in ovariectomized C57BL/6. Our data suggest that tectorigenin is a potential pharmacological choice for osteoporosis.

Impact of muscle atrophy on bone metabolism and bone strength: implications for muscle-bone crosstalk with aging and disuse.

Bone fractures in older adults are often preceded by a loss of muscle mass and strength. Likewise, bone loss with prolonged bed rest, spinal cord injury, or with exposure to microgravity is also preceded by a rapid loss of muscle mass. Recent studies using animal models in the setting of hindlimb unloading or botulinum toxin (Botox) injection also reveal that muscle loss can induce bone loss. Moreover, muscle-derived factors such as irisin and leptin can inhibit bone loss with unloading, and knockout of catabolic factors in muscle such as the ubiquitin ligase Murf1 or the myokine myostatin can reduce osteoclastogenesis. These findings suggest that therapies targeting muscle in the setting of disuse atrophy may potentially attenuate bone loss, primarily by reducing bone resorption. These potential therapies not only include pharmacological approaches but also interventions such as whole-body vibration coupled with resistance exercise and functional electric stimulation of muscle.

Bacillus clausii inhibits bone loss by skewing Treg-Th17 cell equilibrium in postmenopausal osteoporotic mice model.

Postmenopausal osteoporosis is one of most commonly occurring skeletal diseases leading to bone loss and fragility. Probiotics have been associated with various immunomodulatory properties and thus can be exploited to enhance bone health. In the present study, we report, to our knowledge for the first time, that oral administration of Bacillus clausii (BC) in postmenopausal osteoporotic (OVX) mice model enhances bone health. BC was selected as probiotic of choice due to its established immunomodulatory properties. BC skews the Treg-Th17 cell balance in vivo by inhibiting osteoclastogenic Th17 cells and promoting antiosteoclastogenic Treg cell development in postmenopausal osteoporotic mice. Mice were divided into three groups (sham, OVX, and OVX + BC), and BC was administered orally in drinking water for 6 wk post-ovariectomy. At the end of experiment, mice were sacrificed and bones were analyzed for various parameters, along with lymphoid tissues for Treg-Th17 cells and serum cytokines. We observed that BC administration enhanced bone health. This effect of BC administration was found due to skewing of Treg-Th17 cell balance (enhanced Treg and decreased Th17 cells) in vivo. BC administration reduced levels of proinflammatory cytokines (interleukin [IL]-6, IL-17, IFN-γ and tumor necrosis factor-α) and increased levels of anti-inflammatory cytokine (IL-10). The present study strongly supports and establishes the osteoprotective potential of BC leading to enhanced bone health in postmenopausal osteoporotic mice model.

Icariin Restores Bone Structure and Strength in a Rat Model of Chronic High-Dose Alcohol-Induced Osteopenia

Background/Aims: Chronic alcohol abuse is an important risk factor for osteopenia. However, few studies have focused on the efficacy and mechanism of action of icariin on alcohol-induced osteopenia. The aim of this study was to investigate the efficacy and underlying mechanism of action of icariin in the treatment of chronic high-dose alcohol-induced osteopenia in a rat model. Methods: Thirty-six adult male Sprague-Dawley rats were randomly divided into four groups: sham, alcohol, and low-dose and high-dose icariin groups. Bone volume fraction (BV/TV), bone mineral density (BMD), bone biomechanical properties, and bone morphology were assessed after 16 weeks. Reverse-transcription PCR was used to detect mRNA expression levels of alkaline phosphatase (ALP), collagen type I (Col I), osteocalcin (OC), runt-related transcription factor 2 (Runx2), bone morphogenetic protein-2 (BMP-2), and osteoprotegerin (OPG). Results: Bone metabolic markers and biomechanical properties in the alcohol group were decreased significantly compared with the sham group. BV/TV, BMD, mineral apposition rate (MAR), percent trabecular area (%Tb.Ar), and bone biomechanical properties were elevated in the low-dose and high-dose icariin groups relative to the alcohol group. ALP, Col I, OC, Runx2, BMP-2, and OPG mRNA levels in the icariin group were significantly elevated in comparison with the alcohol group. Conclusion: Icariin can prevent overall progression of chronic high-dose alcohol-induced osteopenia in a rat model, in a dose-dependent manner. Icariin promotes bone formation and inhibits bone loss, and effectively restores bone structure and strength in chronic high-dose alcohol-induced osteopenic rats. Bone metabolism reversal is evidenced by increased BV/TV, BMD, MAR, %Tb.Ar, and biomechanical properties and elevated ALP, Col I, OC, Runx2, BMP-2, and OPG mRNA levels.

Evolution of Periodontal Disease: Immune Response and RANK/RANKL/OPG System.

The aim of this study was to evaluate markers of bone loss and immune response present in evolution of periodontal disease. One hundred and two Wistar rats were divided into three animals groups: PD0, without ligation and PD15 days and PD60 days, submitted to ligation placement with a sterile 3-0 silk cord in the cervical region of the upper first molar on both sides. Samples were obtained from the gingival tissue for histomorphometric analysis, immunohistochemical analysis of RANK, RANKL, OPG, characterization of the inflammatory infiltrate, quantification of nitric oxide, MCP-1, RANTES, IP10 chemokines, and expression of the TGF-b1, VEG, and bFGF. The number of inflammatory cells in gingival tissue was higher in PD60 samples. The collagen content and the area occupied by birefringent collagen fibers were lower for PD60. Differential leukocyte counting showed that there was a significantly higher polymorphonuclear influx in group PD15, while PD60 showed a greater number of lymphocytes. PD60 showed higher RANTES, IP-10, MCP-1 gene transcripts, as well as a higher nitric oxide concentration. Clinical evaluation revealed that the PD60 group presented an increase in furcal area. In conclusion, in this animal model the increase of RANK/RANKL and HGF markers is related to a specific immune response, and probably contributed to the evolution of periodontal disease. Investigating the effect of these biomarkers can help in targeted therapy for bone resorption, since blocking these can inhibit bone loss.

Ethanolic Extract of Rubus coreanus Fruits Inhibits Bone Marrow-Derived Osteoclast Differentiation and Lipopolysaccharide-Induced Bone Loss

The inhibition of osteoclast differentiation/bone resorption is a well-known therapeutic strategy for controlling pathological and postmenopausal bone loss. Natural products that specifically inhibit osteoclastogenesis could therefore be developed as antiresorptive drugs for the treatment of metabolic bone disorders characterized by excessive osteoclastic bone resorption. We therefore examined the effects of Rubus coreanus extract (eeRc) on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced differentiation of bone marrow macrophages (BMMs) into osteoclasts and pit formation in vitro. Additionally, the in vivo effects of the eeRc were observed in mice with lipopolysaccharide (LPS)-induced bone erosion. In this study, we found that the ethanolic extract of Rubus coreanus fruits considerably suppressed the RANKL-induced differentiation of primary BMMs into osteoclasts and bone-resorbing activity of mature osteoclasts. Oral administration of eeRc attenuated LPS-induced bone loss in vivo, as demonstrated by the reversal of LPS-induced reduction in bone volume per tissue volume, bone mineral density, and trabecular number to some extent in eeRc-treated mice. In addition, eeRc slightly decreased the serum levels of C-terminal telopeptide fragments of type I collagen, the collagen-breakdown product generated by osteoclasts. Collectively, our results indicate that eeRc has the potential to inhibit bone loss by blocking osteoclast differentiation and could therefore be a promising natural product for the prevention and/or treatment of inflammatory bone loss.

Treatment of rotenone induced neurodegeneration by taurine and hesperidin

Taurine (2-aminoethane sulphonic acid) is a sulphonic acid which is derived from cysteine and is widely distributed in animal tissues. It is one of the most abundant amino acid in mammals and plays several crucial roles including modulation of calcium signaling, osmoregulation and membrane stabilization. Hesperidin occurs in the cells in crystalline, feather-like aggregates or sphaerocrytalline masses and it exhibits pharmacological and biological properties such as anti-inflammatory, anticarcinogenic, inhibit bone loss, lowering of lipid, hypoglycaemic and antioxidant activities. The current study was performed to evaluate the effect of taurine and hesperidin on neurodegeneration resulted from rotenone administration by a dose of 1.5 mg/kg b.wt three times per week for two months. Also we summarize recent findings emphasizing the role of catecholamines neurotransmitters, Tyrosine hydroxylase and oxidative stress in neurodegenerative disease model. These rats received taurine and hesperidin through gastric intubation daily for one month after rotenone administration. The results revealed that taurine and hesperidin treatment significantly ameliorated the decreased levels of the catecholamines neurotransmitters and Tyrosine hydroxylase which were decreased as after rotenone injection. Moreover, taurine and hesperidin treatment ameliorated lipid peroxidation and catalase levels.

Oral administration of kaempferol inhibits bone loss in rat model of ovariectomy-induced osteopenia.

Postmenopausal osteoporosis and osteoporotic fractures constitute an increasing problem in developing countries. Kaempferol, isolated from seeds of Cuscuta chinensis, is an active flavonoid inhibiting in vitro osteoclast activity. The aim of the presented research was an assessment of kaempferol effect on estrogen-deficiency-induced bone structure disturbances in rats. The study was performed on 24 Wistar female rats divided into 3 groups: SHAM - rats undergoing a "sham" surgery, OVX-C - control group of animals that underwent ovariectomy, OVX-K - rats undergoing ovariectomy and receiving kaempferol for 8 weeks (from day 56 to day 112). In the OVX-K group, contrary to the OVX-C one, there was no significant decrease in femoral bone mineral density (BMD). A significant increase in Young's modulus was observed in the OVX-K group compared to the OVX-C (15.33±2.51GPa vs. 11.14±1.93GPa, p<0.05). A decreased bone turnover was detected in the OVX-K group. Tissue volume ratio (BV/TV) and trabecular bone perimeter were increased in the OVX-K group compared to the OVX-C one (0.241±0.037 vs. 0.170±0.022, p<0.05 and 15.52±2.78mm vs. 9.67±3.07mm, p<0.05, respectively). Kaempferol has a beneficial influence on estrogen-deficiency-induced disturbances of bone structure in rats.

Downregulation of miR-10b promotes osteoblast differentiation through targeting Bcl6.

MicroRNAs (miRNAs or miRs) have been shown to play a critical role in osteoblast differentiation. miR-10b has been found to be downregulated during osteoblast differentiation; however, its precise effect on osteoblast differentiation remains unknown. In this study, we aimed to investigate the potential role of miR-10b and the potential underlying mechanism in regulating osteoblast differentiation. We found that miR-10b was downregulated during osteoblast differentiation. Overexpression of miR-10b inhibited osteoblast differentiation, whereas the suppression of miR-10b promoted osteoblast differentiation. Bioinformatics analysis and the dual-luciferase reporter assay demonstrated that miR-10b could target the 3'-untranslated regions of Bcell lymphoma6 (Bcl6) which is an important regulator of osteoblast differentiation. Real‑time quantitative polymerase chain reaction and western blot analysis showed that miR-10b directly regulated Bcl6 expression. Further experiments showed that the overexpression of miR-10b increased the expression of signal transducer and activator of transcription1 (STAT1) and blocked Runt-related transcription factor2 (Runx2) nuclear translocation, whereas miR-10b suppression showed an opposite effect. Moreover, the miR-10b suppression-induced effects were partially reversed by Bcl6 knockdown. Taken together, our study suggests that miR-10b contributes to osteoblast differentiation through targeting Bcl6, providing a novel insight into understanding the molecular mechanism underlying osteoblast differentiation and suggesting a potential target for inhibiting bone loss.

Adipokine Chemerin Bridges Metabolic Dyslipidemia and Alveolar Bone Loss in Mice.

Chemerin is an adipokine that regulates adipogenesis and metabolic functions of mature adipocytes mainly through the activation of chemokine-like receptor 1 (CMKLR1). Elevated levels of chemerin have been found in individuals with obesity, type 2 diabetes, and osteoporosis. This adipokine was identified as an inflammatory and metabolic syndrome marker. Considering that the association between metabolic syndrome and bone health remains unclear, the present study aimed to clarify the role of chemerin in the pathophysiology of bone loss induced by dyslipidemia, particularly modulating osteoclastogenesis. In vitro analyses showed a downregulation of CMKLR1 at the early stage of differentiation and a gradual increase at late stages. Strikingly, chemerin did not modify osteoclast differentiation markers or osteoclast formation; however, it increased the actin-ring formation and bone resorption activity in mature osteoclasts. The increased bone resorption activity induced by chemerin was effectively inhibited by CMKLR1 antagonist (CCX832). Chemerin boosting mature osteoclast activity involves ERK5 phosphorylation. Moreover, two models of dyslipidemia (high-fat diet [HFD]-treated C57/BL6 and db/db mice) exhibited significantly increased level of chemerin in the serum and gingival tissue. Morphometric analysis showed that HFD-treated and db/db mice exhibited increased alveolar bone loss compared to respective control mice, which was associated with an up-regulation of chemerin, CMKLR1 and cathepsin K mRNA expression in the gingival tissue. The treatment of db/db mice with CCX832 effectively inhibited bone loss. Antagonism of chemerin receptor also inhibited the expression of cathepsin K in the gingival tissue. Our results show that chemerin not only increases osteoclasts activity in vitro, but also that increased level of chemerin in dyslipidemic mice plays a critical role in bone homeostasis. © 2016 American Society for Bone and Mineral Research.

Effects of electromagnetic fields on bone loss in hyperthyroidism rat model.

Optimal therapeutics for hyperthyroidism-induced osteoporosis are still lacking. As a noninvasive treatment, electromagnetic fields (EMF) have been proven to be effective for treating osteoporosis in non-hyperthyroidism conditions. We herein systematically evaluated the reduced effects of EMF on osteoporosis in a hyperthyroidism rat model. With the use of Helmholtz coils and an EMF stimulator, 15 Hz/1 mT EMF was generated. Forty-eight 5-month-old male Sprague-Dawley rats were randomly divided into four different groups: control, levothyroxine treated (L-T4), EMF exposure + levothyroxine (EMF + L-T4), and EMF exposure without levothyroxine administration (EMF). All rats were treated with L-T4 (100 mg/day) except those in control and EMF groups. After 12 weeks, the results obtained from bone mineral density analyses and bone mechanical measurements showed significant differences between L-T4 and EMF + L-T4 groups. Micro CT and bone histomorphometric analyses indicated that trabecular bone mass and architecture in distal femur and proximal tibia were augmented and restored partially in EMF + L-T4 group. In addition, bone thyroid hormone receptors (THR) expression of hyperthyroidism rats was attenuated in EMF + L-T4 group, compared to control group, which was not observed in L-T4 group. According to these results, we concluded that 15 Hz/1 mT EMF significantly inhibited bone loss and micro architecture deterioration in hyperthyroidism rats, which might occur due to reduced THR expression caused by EMF exposure. Bioelectromagnetics. 38:137-150, 2017. © 2016 Wiley Periodicals, Inc.

Computer modelling of bone's adaptation: the role of normal strain, shear strain and fluid flow.

Bone loss is a serious health problem. In vivo studies have found that mechanical stimulation may inhibit bone loss as elevated strain in bone induces osteogenesis, i.e. new bone formation. However, the exact relationship between mechanical environment and osteogenesis is less clear. Normal strain is considered as a prime stimulus of osteogenic activity; however, there are some instances in the literature where osteogenesis is observed in the vicinity of minimal normal strain, specifically near the neutral axis of bending in long bones. It suggests that osteogenesis may also be induced by other or secondary components of mechanical environment such as shear strain or canalicular fluid flow. As it is evident from the literature, shear strain and fluid flow can be potent stimuli of osteogenesis. This study presents a computational model to investigate the roles of these stimuli in bone adaptation. The model assumes that bone formation rate is roughly proportional to the normal, shear and fluid shear strain energy density above their osteogenic thresholds. In vivo osteogenesis due to cyclic cantilever bending of a murine tibia has been simulated. The model predicts results close to experimental findings when normal strain, and shear strain or fluid shear were combined. This study also gives a new perspective on the relation between osteogenic potential of micro-level fluid shear and that of macro-level bending shear. Attempts to establish such relations among the components of mechanical environment and corresponding osteogenesis may ultimately aid in the development of effective approaches to mitigating bone loss.

Inhibition of bone loss with surface-modulated, drug-loaded nanoparticles in an intraosseous model of prostate cancer

Advanced-stage prostate cancer usually metastasizes to bone and is untreatable due to poor biodistribution of intravenously administered anticancer drugs to bone. In this study, we modulated the surface charge/composition of biodegradable nanoparticles (NPs) to sustain their blood circulation time and made them small enough to extravasate through the openings of the bone's sinusoidal capillaries and thus localize into marrow. NPs with a neutral surface charge, achieved by modulating the NP surface-associated emulsifier composition, were more effective at localizing to bone marrow than NPs with a cationic or anionic surface charge. These small neutral NPs (~150nm vs. the more usual ~320nm) were also ~7-fold more effective in localizing in bone marrow than large NPs. We hypothesized that NPs that effectively localize to marrow could improve NP-mediated anticancer drug delivery to sites of bone metastasis, thereby inhibiting cancer progression and preventing bone loss. In a PC-3M-luc cell-induced osteolytic intraosseous model of prostate cancer, these small neutral NPs demonstrated greater accumulation in bone within metastatic sites than in normal contralateral bone as well as co-localization with the tumor mass in marrow. Significantly, a single-dose intravenous administration of these small neutral NPs loaded with paclitaxel (PTX-NPs), but not anionic PTX-NPs, slowed the progression of bone metastasis. In addition, neutral PTX-NPs prevented bone loss, whereas animals treated with the rapid-release drug formulation Cremophor EL (PTX-CrEL) or saline (control) showed >50% bone loss. Neutral PTX-NPs did not cause acute toxicity, whereas animals treated with PTX-CrEL experienced weight loss. These results indicate that NPs with appropriate physical and sustained drug-release characteristics could be explored to treat bone metastasis, a significant clinical issue in prostate and other cancers.

Inductive Effect of Palmatine on Apoptosis in RAW 264.7 Cells.

Osteoporosis is a serious public health problem characterized by low bone density and deterioration of the bone microarchitecture. Current treatment options target either osteoclast resorption or osteoblast formation. It has been reported that berberine, a close structural analog of palmatine, inhibited bone loss in an osteoporosis model. In this study, osseous metabolism was observed in vitro with osteoclast bone resorbing cells. We proved that mouse preosteoclastic cell line (RAW 264.7) has a higher sensitivity to palmatine than mouse osteoblastic cell line (MC3T3-E1); the cell survival rates significantly decreased at 40 μM palmatine. The NO2 − level, a metabolic product of nitric monoxide (NO), and iNOS mRNA expression, an osteoclast with NO induced enzyme, also increased with higher dosage of palmatine. Furthermore, it was recognized that the cell viability decrease from palmatine was caused by apoptosis rather than necrosis. Additionally, osteoclast apoptosis from palmatine did not occur when iNOS was inhibited with NG-nitro-L-arginine methyl ester hydrochloride (pan NOS inhibitor). These results indicate that palmatine plays an important role in osteoclast apoptosis via the NOS system. Hence, palmatine could be considered as a viable pharmaceutical candidate for osteoporosis bone resorption inhibitor.

Osteoporosis Recovery by Antrodia camphorata Alcohol Extracts through Bone Regeneration in SAMP8 Mice.

Antrodia camphorata has previously demonstrated the efficacy in treating cancer and anti-inflammation. In this study, we are the first to evaluate Antrodia camphorata alcohol extract (ACAE) for osteoporosis recovery in vitro with preosteoblast cells (MC3T3-E1) and in vivo with an osteoporosis mouse model established in our previous studies, ovariectomized senescence accelerated mice (OVX-SAMP8). Our results demonstrated that ACAE treatment was slightly cytotoxic to preosteoblast at 25 μg/mL, by which the osteogenic gene expression (RUNX2, OPN, and OCN) was significantly upregulated with an increased ratio of OPG to RANKL, indicating maintenance of the bone matrix through inhibition of osteoclastic pathway. Additionally, evaluation by Alizarin Red S staining showed increased mineralization in ACAE-treated preosteoblasts. For in vivo study, our results indicated that ACAE inhibits bone loss and significantly increases percentage bone volume, trabecular bone number, and bone mineral density in OVX-SAMP8 mice treated with ACAE. Collectively, in vitro and in vivo results showed that ACAE could promote osteogenesis and prevent bone loss and should be considered an evidence-based complementary and alternative medicine for osteoporosis therapy through the maintenance of bone health.

The determination of apoptosis rates on articular cartilages of ovariectomized rats with and without alendronate treatment.

Osteoporosis (OP) is a major health problem characterized by compromised bone strength. Osteoarthritis (OA) is a joint disease that progresses slowly and is characterized by breakdown of the cartilage matrix. Alendronate (ALN), a nitrogen-containing bisphosphonate (BIS), inhibits bone loss and increases bone mineralization, and has been used clinically for the treatment of OP. It is still controversial whether BIS is effective in inhibiting the progression of OA. Chondrocyte apoptosis has been described in both human and experimentally induced OA models. In our study we aimed to detect whether ALN could protect articular cartilage from degeneration and reduce apoptosis rates in experimentally OA induced rats. For this rats were ovariectomized (ovex), nine weeks after operation rats were injected 30 µg/kg/week ALN subcutaneously for six weeks. After six weeks articular cartilages were obtained. We did Safranin O staining and Mankin and Pritzker scorings to evaluate degeneration and investigated the expressions of p53, cleaved caspase 3, Poly ADP-ribose (PAR), Poly ADP-ribose polymerase 1 (PARP 1), and applied TUNEL technique to determine apoptotis rates. We found a significant decrease in glycosaminoglycan (GAG) amount and increased apoptosis which indicates damage on articular cartilages of ovex rats. GAG amount was higher and apoptosis rate was lower on articular cartilages of ALN treated ovex rats compared to the ovex group. In contrary to studies showing that early ALN treatment has a protective effect, our study shows late ALN treatment has a chondroprotective effect on articular cartilage since we treated rats nine weeks after ovariectomy.

Recognition of the Causative Agent of “Phossy Jaw” and “Fragile Femur” in Fumes Arising from White Phosphorus

GRAPHICAL ABSTRACT

Inhibition of Osteoclastogenesis and Bone Resorption in vitro and in vivo by a prenylflavonoid xanthohumol from hops

Excessive RANKL signaling leads to superfluous osteoclast formation and bone resorption, is widespread in the pathologic bone loss and destruction. Therefore, targeting RANKL or its signaling pathway has been a promising and successful strategy for this osteoclast-related diseases. In this study, we examined the effects of xanthohumol (XN), an abundant prenylflavonoid from hops plant, on osteoclastogenesis, osteoclast resorption, and RANKL-induced signaling pathway using both in vitro and in vivo assay systems. In mouse and human, XN inhibited osteoclast differentiation and osteoclast formation at the early stage. Furthermore, XN inhibited osteoclast actin-ring formation and bone resorption in a dose-dependent manner. In ovariectomized-induced bone loss mouse model and RANKL-injection-induced bone resorption model, we found that administration of XN markedly inhibited bone loss and resorption by suppressing osteoclast activity. At the molecular level, XN disrupted the association of RANK and TRAF6, resulted in the inhibition of NF-κB and Ca2+/NFATc1 signaling pathway during osteoclastogenesis. As a results, XN suppressed the expression of osteoclastogenesis-related marker genes, including CtsK, Nfatc1, Trap, Ctr. Therefore, our data demonstrated that XN inhibits osteoclastogenesis and bone resorption through RANK/TRAF6 signaling pathways. XN could be a promising drug candidate in the treatment of osteoclast-related diseases such as postmenopausal osteoporosis.