Glucocorticoid-induced Osteoporosis Rats Research Articles

The Putative Role of Nigella Sativa Oil versus Calcium and Vitamin D in Modulating the Glucocorticoid-Induced Osteoporosis in Rats: Histological and Immunohistochemical Study.

The Putative Role of Nigella Sativa Oil versus Calcium and Vitamin D in Modulating the Glucocorticoid-Induced Osteoporosis in Rats: Histological and Immunohistochemical Study.

The protective effects of tocotrienols and coenzyme Q10 against glucocorticoid-induced osteoporosis in rats: Potential roles of Nrf2, Bcl-2, and autophagy.

The protective effects of tocotrienols and coenzyme Q10 against glucocorticoid-induced osteoporosis in rats: Potential roles of Nrf2, Bcl-2, and autophagy.

Antiosteoporosis and bone protective effect of alpinumisoflavone in steroid-induced osteoporosis rats via alteration of apoptosis, inflammatory and RANK/RANKL/OPG signaling pathway

Objective: To estimate the bone protective effect of alpinumisoflavone, a natural prenylated isoflavonoid, against glucocorticoid-induced osteoporosis in rats. Methods: Male Wistar rats received intramuscular administration of dexamethasone (4 mg/mL) at a dose level of 7 mg/kg for 5 weeks, and then alpinumisoflavone (5, 10, and 15 mg/kg) and alendronate (2 mg/kg) from 2 weeks. The body weight and organ weight (femoral, vagina, and uterus) were estimated. MicroCT analysis, bone turnover markers, bone parameters, oxidative stress parameters, and inflammatory cytokines were estimated. mRNA expressions of related genes were also estimated. Results: Alpinumisoflavone remarkably boosted body weight and organ weight (ureters and vagina), improved microCT analysis parameters, and boosted levels of bone markers. Besides, alpinumisoflavone considerably (P<0.001) restored the level of bone turnover markers and oxidative stress parameters, remarkably suppressed the level of cytokines such as interleukin-1β, interleukin-6, tumor necrosis factor-α, and increased transforming growth factor-β and insulin-like growth factor. It also significantly restored the osteoprotegerin (OPG, RANKL, and OPG/RANKL ratio) levels and the mRNA expression of Caspase (3, 6, 7, 9), BMPs, OPN, ALP, RUNX2, and OCN. Conclusions: The current result suggests the bone protective effect of alpinumisoflavone against glucocorticoid-induced osteoporosis in rats.

Anti-inflammatory, antiosteoporotic, and bone protective effect of hydroxysafflor yellow A against glucocorticoid-induced osteoporosis in rats.

Osteoporosis is a common condition worldwide, affecting millions of people. Women are more commonly affected than men, and the risk increases with age. Inflammatory reaction plays a crucial role in the expansion of osteoporosis. Osteoporosis is characterized by a gradual decline in bone density and bone tissue quality, which increases fragility and raises the risk of fractures. We scrutinized the anti-osteoporosis effect of hydroxysafflor yellow A (HYA) against glucocorticoid-induced osteoporosis (GIOP) in rats. In-silico study was carried out on EGFR receptor (PDBID: 1m17), Estrogen Alpha (PDB id: 2IOG), MTOR (PDB id: 4FA6), RANKL (PDB id: 1S55), and VEGFR2 (PDB id: 1YWN) protein. For this investigation, Sprague-Dawley (SD) rats were used, and they received an oral dose of HYA (5, 10, and 20 mg/kg, b.w.) along with a subcutaneous injection of dexamethasone (0.1 mg/kg/day) to induce osteoporosis. The biomechanical, bone parameters, antioxidant, cytokines, inflammatory, nutrients, hormones, and urine parameters were estimated. HYA treatment significantly suppressed the body weight and altered the organ weight. HYA treatment remarkably suppressed the level of alkaline phosphatase, acid phosphatase, and improved the level of bone mineral density (total, proximal, mild, and dis). HYA treatment restored the level of calcium (Ca), phosphorus (P), estradiol (E2), and parathyroid hormone near to the normal level. HYA treatment remarkably altered the level of biomechanical parameters, antioxidant, cytokines, urine, and inflammatory parameters. HYA treatment altered the level of osteoprotegerin (OPG), receptor activator of nuclear factor kappa beta (RANKL) and RANKL/OPG ratio. The result clearly showed the anti-osteoporosis effect of HYA against GIOP-induced osteoporosis in rats via alteration of antioxidant, cytokines, inflammatory, and bone protective parameters.

Dendrobine Ameliorates Glucocorticoid-Induced Osteoporosis by Promoting Osteogenesis through JNK/p38 MAPK Pathway Activation and GR Nuclear Translocation Inhibition.

Glucocorticoid-induced osteoporosis (GIOP) is the common reason for secondary osteoporosis. Dendrobine (DEN) is the major biologically active component of Dendrobium officinale with anti-inflammatory and antiaging properties. Whether DEN could alleviate osteogenic inhibition in GIOP rats is still unknown. The influence on osteogenic function caused by DEN on dexamethasone-treated bone marrow mesenchymal stem cells and rats was observed. The in vitro results showed that DEN reversed the inhibition of osteogenic differentiation by dexamethasone. Moreover, DEN supplementation attenuated dexamethasone-induced bone loss in vivo. DEN activated JNK and p38 MAPK pathways and restrained GR nuclear translocation, which could be prevented by the JNK (SP600125) or p38 (SB203580) pathway inhibitor. This study verified that DEN alleviated dexamethasone-induced nuclear translocation of GR, and inhibition of osteogenesis via JNK and p38 pathways, laying the foundation for DEN as a therapeutic agent for GIOP.

Alleviation of Glucocorticoid-Induced Osteoporosis in Rats by Ethanolic Reynoutria multiflora (Thunb.) Moldenke Extract.

Secondary osteoporosis is frequently due to the use of high-dose glucocorticoids (GCs). The existing strategy for managing glucocorticoid-induced osteoporosis (GIOP) is considered insufficient and remains in a state of ongoing evolution. Therefore, it is crucial to develop more precise and effective agents for the treatment of GIOP. The constituents of Reynoutria multiflora (Thunb.) Moldenke, specifically Polygonum multiflorum (PM) Thunb, have previously shown promise in mitigating osteopenia. This study aimed to investigate the therapeutic effects of an ethanolic PM extract (PMR30) against GIOP in male rats. Prednisone (6 mg/kg/day, GC) was continuously administered to rats to induce GIOP, and they were subjected to treatment with or without ethanolic PMR30 for a duration of 120 days. Serum was collected for biochemical marker analysis. Bone histomorphometric, histological, and TUNEL analyses were performed on tibia samples. The protein expressions of LC3, Agt5, and Beclin 1 in the femur underwent examination through western blotting. Prolonged and excessive GC treatment significantly impeded bone formation, concomitant with reduced bone mass and body weight. It also suppressed OCN and OPG/RANKL in serum, and decreased Beclin 1 and LC3 in bone. Simultaneously, there was an elevation in bone resorption markers and apoptosis. Treatments with both high dose and low dose of PMR30 alleviated GIOP, stimulated bone formation, and upregulated OCN and OPG/RANKL, while suppressing TRACP-5b, CTX-I, and apoptosis. The impact of PMR30 possibly involves the enhancement of autophagy proteins (LC3, Agt5, and Beclin 1) and the inhibition of apoptosis within the bone. PMR30 holds promise as a prospective therapeutic agent for preventing and treating GIOP.

Association between dietary selenium intake and the prevalence of osteoporosis and its role in the treatment of glucocorticoid-induced osteoporosis

BackgroundLong-term glucocorticoid therapy may lead to osteoporosis (OP). Selenium (Se) is an essential microelement for human health and bone health. This study evaluated the association between dietary Se intake and the prevalence of OP and further explored the potential therapeutic effect of Se on glucocorticoid-induced OP (GIOP) in vivo and in vitro.MethodsData were collected from a population-based cross-sectional study conducted in our hospital. OP is diagnosed based on bone mineral density (BMD) measurements using compact radiographic absorptiometry. Dietary Se intake was assessed using a semi-quantitative food frequency questionnaire. The association between dietary Se intake and OP prevalence was analyzed by multivariable logistic regression. In animal experiments, male Sprague–Dawley rats were intramuscularly injected with dexamethasone (1 mg/kg) daily to induce GIOP, while different doses of Se were supplemented in rat drinking water for 60 d. BMD and biomechanical parameters of rat femur were measured. The histopathological changes of the femur were observed by HE staining, the number of osteoclasts was observed by TRAP staining, and OCN positive expression was detected by immunohistochemical staining. OPG, RANKL, Runx2, and BMP2 in rat femur were detected by Western blot. Bone turnover markers and oxidative stress markers were measured using commercial kits. MC3T3-E1 cells were induced to osteogenic differentiation, stimulated with DXM (100 μM), and/or treated with Se at different doses. Cell proliferation and apoptosis were assessed by CCK-8 and flow cytometry. ALP activity was detected by ALP staining and cell mineralization was observed by alizarin red staining.ResultsParticipants with lower dietary Se intake had higher OP prevalence. Se supplementation improved BMD, biomechanical parameters, and histopathological changes of the femur in GIOP rats. Se supplementation also suppressed DXM-induced changes in bone turnover- and oxidative stress-related markers. Under DXM conditions, Se treatment induced MC3T3-E1 cell proliferation, ALP activity, and mineralization.ConclusionLower Dietary Se intake is associated with OP prevalence. Moreover, Se takes a position in bone protection and anti-oxidative stress in GIOP models. Therefore, Se may be a complementary potential treatment for GIOP.

Molecular Complex of HSIM-loaded Polymeric Nanoparticles: Potential Carriers in Osteoporosis.

Statins, especially simvastatin promote bone formation by stimulating the activity of osteoblasts and suppressing osteoclast activity via the BMP-Smad signaling pathway. Statins present the liver first-pass metabolism. This study attempts to fabricate and evaluate simvastatin functionalized hydroxyapatite encapsulated in poly(lactic-co-glycolic) acid (PLGA) nanoparticles (HSIM-PLGA NPs) administered subcutaneously with sustained release properties for effective management of osteoporosis. Simvastatin functionalized hydroxyapatite (HSIM) was prepared by stirring and validated by docking studies, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Further, HSIM-loaded PLGA nanoparticles (HSIM-PLGA NPs) were developed via the solvent emulsification method. The nanoparticles were evaluated for zeta potential, particle size, entrapment efficiency, stability studies, and in vitro drug release studies. in vitro binding affinity of nanoparticles for hydroxyapatite was also measured. Bone morphology and its effect on bone mineral density were examined by using a glucocorticoid-induced osteoporosis rat model. The optimized nanoparticles were found to be amorphous and showed no drug-polymer interaction. The particle size of formulated nanoparticles varied from 196.8 ± 2.27nm to 524.8 ± 5.49 nm and the entrapment efficiency of nanoparticles varied from 41.9 ± 3.44% to 70.8 ± 4.46%, respectively. The nanoparticles showed sustained release behaviour (75% in 24 hr) of the drug followed by non-fickian drug release. The nanoparticles exhibited high binding affinity to bone cell receptors, increasing bone mineral density. A significant difference in calcium and phosphorous levels was observed in disease and treatment rats. Porous bone and significant improvement in porosity were observed in osteoporotic rats and treated rats, respectively (P < 0.05). Bone-targeting nanoparticles incorporating functionalized simvastatin can target bone. Thus, in order to distribute simvastatin subcutaneously for the treatment of osteoporosis, the developed nanoparticles may act as a promising approach.

An integrated fecal metabolomic based on 1 H-NMR and UPLC-QTOF-MS revealed the preventive mechanism of Gushudan on glucocorticoid-induced osteoporotic rats.

Gushudan (GSD) has the effect of strengthening bones and nourishing kidneys. However, its specific intervention mechanism still remains unclear. In this study, to investigate the pathogenesis of glucocorticoid-induced osteoporosis (GIOP) and the preventive mechanism of GSD on GIOP, fecal metabolomics based on 1 H-NMR and ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry method was established. The changes in endogenous metabolites and the relevant metabolic pathways in the control group, model group, and GSD treatment group were investigated via multivariate statistical analysis. As a result, a total of 39 differential metabolites were identified. Of these, 22 metabolites, such as L-methionine, guanine, and sphingosine, were newly discovered as differential metabolites of GIOP. Amino acid metabolism, energy metabolism, intestinal flora metabolism, and lipid metabolism were significantly changed in the fecal profiles of GIOP rats, and GSD could play an anti-osteoporosis role by regulating these metabolic pathways. Finally, compared with our previous study of the GSD to prevent kidney yang deficiency syndrome, this study suggested that there were some identical differential metabolites and metabolic pathways. It showed that there was some correlation among the metabolic profiles of the intestine, kidney, and bone in GIOP rats. Therefore, this study offered new insights into the in-depth understanding of the pathogenesis of GIOP and the intervention mechanism of GSD.

Lactobacillus plantarum LP45 inhibits the RANKL/OPG signaling pathway and prevents glucocorticoid-induced osteoporosis.

To examine the potential effect of the probiotic strain Lactobacillus plantarum LP45 on osteoporosis and to explore the involved molecular mechanisms. A rat model of glucocorticoid-induced osteoporosis (GIO) was established, which was also orally administered with increasing doses of LP45 for 8 weeks. After the termination of the 8-week treatment, the tibia and femur bones of rats were analyzed for bone histomorphometry, bone mineral content (BMC), and bone mineral density (BMD). Femoral biomechanics were assessed. In addition, levels of osteocalcin, tartrate-resistant acid phosphatase 5 (TRAP5), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) in the serum and bone marrow were also measured using ELISA, Western blot, and real time-polymerase chain reaction. GIO caused obvious defects in tibia and femur bone structures, in terms of tissue/bone volume, trabecular separation, trabecular thickness, and trabecular number, which could be rescued by LP45 dose dependently. The GIO-induced reductions in BMC, BMD, osteoblast surfaces per bone surface (BS), as well as elevated osteoclast surface per BS were largely restored by LP45 administration dose-dependently. LP45 also increased femoral biomechanics of GIO rats. Importantly, LP45 dose-dependently restored the changes of osteocalcin, TRAP5, OPG, and RANKL in the serum as well as bone marrow of GIO rats. Oral LP45 administration could significantly prevent bone defects in GIO rats, suggesting its potential as a dietary supplement with beneficial effects against osteoporosis, which might involve the RANKL/OPG signaling pathway.

Efficacy, Mechanism, and Structure-Activity Relationship of 6-Methoxy Benzofuran Derivatives as a Useful Tool for Senile Osteoporosis.

Most patients with senile osteoporosis (SOP) are severely deficient in bone mass, and treatments using bone resorption inhibitors, such as bisphosphonates, have shown limited efficacy. Small-molecule osteogenesis-promoting drugs are required to improve the treatment for this disease. Previously, we demonstrated that a compound with a benzofuran-like structure promoted bone formation by upregulating BMP-2, and it exhibited a therapeutic effect in SAMP-6 mice, glucocorticoid-induced osteoporosis rats, and ovariectomized rats. In this study, aged C57 and SAMP-6 mice models were used to investigate the therapeutic and preventive effects of compound 125 on SOP. scRNA-seq analysis showed that BMP-2 upregulation is the mechanism through which 125 accelerates bone turnover and increases the proportion of osteoblasts. We evaluated the structure-activity relationship of the candidate drugs and found that the derivative I-9 showed significantly higher efficacy than 125 and teriparatide in the zebrafish osteoporosis model. This study provides a foundation for the development of SOP drugs.

Therapeutic Effects of Strontium Ranelate and Risedronate on a Glucocorticoid-Induced Osteoporosis Rat Model: A Comparative Histological and Morphometric study

Therapeutic Effects of Strontium Ranelate and Risedronate on a Glucocorticoid-Induced Osteoporosis Rat Model: A Comparative Histological and Morphometric study

Pterostilbene-isothiocyanate impedes RANK/TRAF6 interaction to inhibit osteoclastogenesis, promoting osteogenesis in vitro and alleviating glucocorticoid induced osteoporosis in rats

Prolonged glucocorticoid treatment often leads to glucocorticoid-induced osteoporosis (GIOP), a common iatrogenic complication. This study has explored the anti-osteoporotic potential of semi-synthetic compound, pterostilbene isothiocyanate (PTER-ITC) in GIOP rat model and bone formation potential in vitro. Dysregulated bone-remodelling leads to osteoporosis. PTER-ITC has shown anti-osteoclastogenic activity in vitro. However, its molecular target remains unidentified, which has been explored in this study through in silico and experimental approaches. Alizarin Red S and von-Kossa staining, and alkaline phosphatase (ALP) activity showed the osteogenic differentiation potential of PTER-ITC in pre-osteoblastic mouse MC3T3-E1 and human hFOB 1.19 cells, further, confirmed through the expressions of osteogenic markers at transcriptional (RT-qPCR) and translational (immunoblotting) levels. The anti-osteoclastogenic property of PTER-ITC was confirmed through inhibition of actin ring formation in mouse RAW 264.7 and human THP-1 macrophagic cells. Molecular docking and molecular dynamic simulation showed that PTER-ITC inhibited the crucial osteoclastogenic RANK/TRAF6 interaction, which was further confirmed biochemically through co-immunoprecipitation assay. Osteoporotic bone architecture [validated through scanning electron microscopy (SEM), X-ray radiography, and micro-computed tomography (µ-CT)], physiology (confirmed through compression testing, Young’s modulus and stress versus strain output) and histology (verified through hematoxylin-eosin, Alizarin Red S, von-Kossa and Masson-trichrome staining) of PTER-ITC-treated GIOP female Wistar rats were assuaged. Osteoporotic amelioration through PTER-ITC treatment was further substantiated through serum biomarkers, like, parathyroid hormone (PTH), ALP, calcium (Ca2+), Procollagen type I N-terminal propeptide (P1NP), and 25-hydroxy vitamin D. In conclusion, this study identifies the molecular target of PTER-ITC in impeding osteoclastogenesis and facilitating osteogenesis to ameliorate osteoporosis.

Antiosteoporosis and bone protective effect of dieckol against glucocorticoid-induced osteoporosis in rats

BackgroundGlucocorticoids (GCs) induce osteoporosis, which results in fractures in the bond, causing significant morbidity. In the conducted study, we examined the antiosteoporosis effect of dieckol against GC-induced osteoporosis in rats.MethodsSprague–Dawley (SD) rats were used for the current study and dexamethasone (2.5 mg/kg) induced osteoporosis in the rats that received the dieckol (test) and alendronate (standard) for 20 weeks. Bone turnover parameters, microCT, antioxidant, inflammatory cytokines, nutrient, and hormones parameters.ResultsDieckol noticeably suppressed the body weight and boosted the uterine and vagina weight. Dieckol considerably altered the level of trabecular number (Tb. N), the bone volume to total volume (BV/TV), trabecular separation (Tb.Sp), bone surface to bone volume (BS/BV), and t​r​a​b​e​c​u​l​a​r thickness (Tb.Th). Dieckol noticeably (P < 0.001) elevated the level of osteocalcin (OC) and alleviated the level of bone Gla protein (BGP), acid phosphatase (ACP), alkaline phosphatase (ALP), and β-CTx. Dieckol markedly boosted the level of malondialdehyde (MDA) and suppressed the level of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) along with the suppression of inflammatory cytokines like TNF-α, IL-1β, and IL-6. Dieckol remarkably increased the level of calcium, potassium, magnesium, and 25 (OH) vitamin D. Dieckol substantially (P < 0.001) boosted the level of estradiol and alleviated the level of parathyroid hormone and tartrate-resistant acid phosphatase (TRAP). Dieckol also suppressed the level of receptor activator of nuclear factor κB ligand (RANKL) and boosted the level of osteoprotegerin (OPG).ConclusionTaken together, our data suggest that dieckol demonstrated the anti-osteoporosis effect against GC-induced osteoporosis in rats.

L-Carnitine ameliorates the osteoporotic changes and protects against simvastatin induced myotoxicity and hepatotoxicity in glucocorticoid-induced osteoporosis in rats.

The current study aimed to discover more effective drugs to treat osteoporosis (OP) with fewer side effects. OP was induced in 24 rats using dexamethasone (DEX) 7mg/kg intramuscular once weekly for four weeks, with six rats as a negative control. The osteoporotic rats were divided into one untreated group (positive control) and three treated groups (n=6) that received L-carnitine (L-Car) (100mg/kg/d), simvastatin (SIMV) (10mg/kg/d), and L-Car +SIMV in the same previous doses, all treatments were orally for four weeks. At the end of the experiment, serum calcium (Ca), phosphorous (P), alkaline phosphatase (ALP), osteoprotegerin (OPG), total antioxidant (TAO), creatine kinase (CK), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were measured. The femur was histopathologically examined. Serum Ca, OPG, and TAO levels increased significantly, while P and ALP levels decreased in the L-Car and SIMV treated groups compared to the DEX-treated group. Moreover, there was a significant decrease in CK, ALT, and AST levels in the L-Car and L-Car + SIMV treated groups compared to the DEX treated group. CONCLUSIONS: L-Car and SIMV have antiosteoporotic effects, as well as a synergistic effect. Moreover, L-Car ameliorates SIMV-induced myotoxicity and hepatoxicity.

Long noncoding RNA TRG-AS1 protects against glucocorticoid-induced osteoporosis in a rat model by regulating miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis.

The long-term treatment of glucocorticoids is a common cause of osteoporosis (OP). This study concentrated on inquiring into the regulatory role and potential mechanisms of TRG-AS1 on dexamethasone (Dex)-induced OP in rats. We adopted Dex to treat rat osteoblasts and rats to simulate in-vitro and in-vivo OP models, respectively. Gain-of-function assays of TRG-AS1, miR-802 and CAB39 were constructed in rat osteoblasts to make certain the influence of TRG-AS1, miR-802 and CAB39 on differentiation, proliferation and apoptosis of rat osteoblasts. TRG-AS1 and CAB39 were down-regulated in the Dex-induced OP model in rats, in contrast to miR-802. Overexpression of TRG-AS1 restrained Dex-induced inhibition of osteogenic differentiation, promoted CAB39/AMPK/SIRT-1 and inhibited NF-κB, while overexpression of miR-802 bridled the inhibitory effect of TRG-AS1 on OP. miR-802 was targeted by TRG-AS1, and inhibited CAB39. Inhibition of either AMPK or SIRT-1 abated the osteogenic differentiation-promoting effect of CAB39. Animal experiments displayed that overexpressing TRG-AS1 alleviated Dex-induced OP in rats. In conclusion, up-regulation of TRG-AS1 protected against glucocorticoid-induced OP in rats by modulating the miR-802-mediated CAB39/AMPK/SIRT-1/NF-κB axis.

Eucommia, Cuscuta, and Drynaria Extracts Ameliorate Glucocorticoid-Induced Osteoporosis by Inhibiting Osteoclastogenesis Through PI3K/Akt Pathway.

Osteoporosis is one of the most common diseases in the world which resulted in heavy socioeconomic burden and a public health threat. Glucocorticoid-induced osteoporosis (GIO) is the most common secondary reason of osteoporosis. Therapeutic strategies using traditional Chinese medicine are under investigation for osteoporosis, with efforts to improve efficacy and clarify the mechanism. The combination of Eucommia, Cuscuta, and Drynaria is widely used in traditional Chinese decoction for osteoporosis treatment, but the experimental efficacy and mechanism are still unclear. Administration of E.C.D. extracts (Eucommia, Cuscuta, and Drynaria) in experimental GIO rats resulted in decreased urinal calcium, phosphorus loss, and decreased expression of RANKL, CTX in serum, increased serum calcium, phosphorus, and OPG level. E.C.D. extracts also improved bone density, structural integrity, and biomechanical function in experimental GIO rats. These finding were associated with E.C.D. extracts’ treatment efficacy to GIO in vivo. The balance between osteoclast and osteoblast activity is essential for bone remodeling and bone related disease. The E.C.D. extracts inhibited Raw 264.7 cell differentiation to osteoclast in vitro. On the other hand, it promoted OPG expression of bone marrow mesenchymal stromal cells (MSCs) which can suppress the osteoclast genesis. E.C.D. extracts also increased the Wnt1 and Runx2 expression which are related to osteoblast formation. It also regulated the paracrine effect of MSC to inhibit osteoclast differentiation. The analysis of HPLC and comprehensive pharmacology identified the constituents of E.C.D. extracts and the potential osteoporosis-related targets mediated by E.C.D. extracts. The KEGG enrichment analysis suggested that PI3K/Akt pathway may be involved in the regulation osteoclast genesis by E.C.D. extracts and the result of Western blot of vitro assays proved it. Collectively, these data demonstrate E.C.D. extracts can inhibit osteoclast differentiation to foster experimental osteoporosis both in vivo and in vitro and it may exert the function of inhibiting osteoclast differentiation through PI3K/Akt pathway.

Effect of Intermittent Fasting on Glucose Homeostasis and Bone Remodeling in Glucocorticoid-Induced Osteoporosis Rat Model

BackgroundThe present study examined the effect of intermittent fasting (IF) on bone mineral content (BMC) and bone mineral density (BMD) and the markers of bone remodeling in a glucocorticoid-induced osteoporosis (GIO) rat model.MethodsForty male rats were allocated to 4 groups (N=10 per group): control group of normal rats; control+IF group (normal rats subjected to IF for 16–18 hr daily for 90 days); dexamethasone (DEX) group: (DEX [0.5 mg i.p.] for 90 days); and DEX+IF group (DEX and IF for 90 days). By the end of the experiment, BMD and BMC in the right tibia were measured. Serum levels of the following were measured: glucose; insulin; triglycerides (TGs); total cholesterol; parathyroid hormone (PTH); osteoprotegerin (OPG); receptor activator of nuclear factor-κB (RANK); bone-resorbing cytokines, including bone deoxypyridinoline (DPD), N-terminal telopeptide of collagen type I (NTX-1), and tartrate-resistant acid phosphatase 5b (TRAP-5b); and bone-forming cytokines, including alkaline phosphatase (ALP) and osteocalcin (OC).ResultsDEX administration for 90 days resulted in significantly increased serum levels of glucose, insulin, TGs, cholesterol, PTH, OPG, DPD, NTX-1, and TRAP-5b and significantly decreased BMD, BMC, and serum levels of RANK, OC, and ALP (all P<0.05). IF for 90 days significantly improved all these parameters (all P<0.05).ConclusionsIF corrected GIO in rats by inhibiting osteoclastogenesis and PTH secretion and stimulating osteoblast activity.

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.

Methylbenzoxime as a therapeutic agent for glucocorticoid-induced osteoporosis in rats

Purpose: To investigate the effect of methylbenzoxime on dexamethasone-induced rat model of osteoporosis.&#x0D; Methods: Osteoporosis rat model was prepared by administration of dexamethasone to rats for sixty days. The rats were then divided into five groups of five animals each: normal control, untreated, and 2, 5 and 10 mg/kg treatment groups. All rats were administered dexamethasone for 60 days. Thereafter, rats in the three treatment groups received daily doses of 2, 5 or 10 mg/kg methylbenzoxime for 15 days, while rats in normal control and untreated groups were given equivalent volumes of normal saline in place of methylbenzoxime. After treatment, the rats were sacrificed, and the femur removed for histological assessment of pathological changes using H&amp;E staining. Expressions of Wntn signalling pathway proteins in osteoblasts were assayed using reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot assays.&#x0D; Results: Methylbenzoxime inhibited osteoblast proliferation, as revealed from 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It increased the expression of osteoprotegerin and downregulated receptor activator for nuclear factor-kappa B ligand. Dexamethasone decreased the expression of Wnt signalling pathway proteins in osteoblasts. However, treatment of the dexamethasone-exposed osteoblasts with methylbenzoxime reversed the inhibition of expressions of Wnt signalling pathway proteins. In vivo studies showed that methylbenzoxime treatment mitigated dexamethasone-induced pathological features in femur. In osteoporotic rats, methylbenzoxime significantly up-regulated the expression of osteocalcin but down-regulated the level of collagen-type I fragments, relative to the untreated group. The effect was significant in the 5 and 10 mg/kg treatment groups, when compared with 2 mg/kg group.&#x0D; Conclusion: Methylbenzoxime prevents dexamethasone-induced osteoporosis in vitro and in rats. Therefore, it is a potential therapeutic agent for the management of osteoporosis.