Glucocorticoid-induced Osteoporosis Rats Research Articles

Effects of the Phosphodiesterase-5 (PDE-5) Inhibitors, Avanafil and Zaprinast, on Bone Remodeling and Oxidative Damage in a Rat Model of Glucocorticoid-Induced Osteoporosis.

BackgroundThe aim of this study was to evaluate the effects of the phosphodiesterase-5 (PDE-5) inhibitors, zaprinast and avanafil, on NO signalling pathway, bone mineral density (BMD), epiphyseal bone width, bone marrow angiogenesis, and parameters of oxidative stress in a rat model of glucocorticoid-induced osteoporosis (GIOP).Material/MethodsTwenty-four 8-month-old male rats in four groups were given a single daily treatment during a 30-day period: an (untreated) control group (n=6): a dexamethasone-treated group (120 μ/kg) (n=6); a group treated with dexamethasone (120 μ/kg) and zaprinast (10 mg/kg) (n=6): and a group treated with dexamethasone (120 μ/kg) and avanafil (10 mg/kg) (n=6). Rat whole body bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA), and bone histology was performed. Also, selected oxidative stress parameters by HPLC method and the other biochemical parameters by ELISA method were measured.ResultsThe GIOP model rats treated with zaprinast and avanafil showed a significant increase in NO, cyclic guanosine monophosphate (cGMP), and protein kinase G (PKG) (NO/cGMP/PKG) signaling-pathway components, and in C-terminal telopeptide of type I collagen (CTX-1), bone marrow angiogenesis, BMD, and epiphyseal bone width, compared with the (untreated) control rats (p<0.05). Levels of pyridinoline (PD) and deoxypyridinoline (DPD) were significantly reduced in the dexamethasone + zaprinast, and dexamethasone + avanafil treatment groups (p<0.05). Malondialdehyde (MDA), ubiquinone-10 (CoQ10), ubiquinol CoQ10 (CoQ10H), and 8-hydroxy-2′-deoxyguanosine (8-OHdG) were significantly increased in the dexamethasone-treated group, compared with the (untreated) controls (p<0.05).ConclusionsIn the GIOP rat model, markers of oxidative stress and bone atrophy were significantly reduced by treatment with the PDE-5 inhibitors, zaprinast and avanafil.

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

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

Gastrodin alleviates glucocorticoid induced osteoporosis in rats via activating the Nrf2 signaling pathways.

BackgroundProlonged and over-dosed administration of glucocorticoids results in more bone remodeling, leading to glucocorticoid-induced osteoporosis, which is primarily due to dysfunction and apoptosis of osteoblasts. The present study investigated the therapeutic effect and molecular mechanism of gastrodin, a natural bioactive compound isolated from the traditional Chinese herbal agent Gastrodia elata, on osteoblastic cells in vivo and in vitro.Materials and MethodsThe anti-dexamethasone (DEX) effects of gastrodin on primary osteoblasts were measured by cell viability, flow cytometry, and western blot analysis in vitro, and also extensively examined in a rat model in vivo.ResultsThe results show that gastrodin pretreatment significantly increased osteoblast viability and alkaline phosphatase activity when exposed to DEX. Alizarin Red staining indicated more calcium deposits formed in the gastrodin pretreatment against DEX group. Gastrodin alleviated DEX-induced reactive oxygen species at both the mitochondrial and cellular levels in osteoblasts. In addition, gastrodin protected primary osteoblasts from caspase3-related apoptosis by reducing the loss in the mitochondrial membrane potential and decreasing the release of DEX-induced cytochrome-C, bax, and apoptosis inducing factor. Gastrodin also antagonized upregulated endoplasmic reticulum stress signals induced by DEX, including the expression of GRP78, CHOP, and phosphorylated eIF2α. Furthermore, gastrodin protected osteoblasts by activating the nuclear factor erythroid derived 2-related factor-2 (Nrf2) pathway. Furthermore, femoral micro-computed tomography scans and biomechanical tests revealed that gastrodin improved bone microstructure and mitigated DEX-induced deterioration in bone quality.ConclusionsThese findings suggest that gastrodin alleviated glucocorticoid-induced osteoporosis in rats by protecting osteoblasts via the Nrf2 regulated mitochondrial and ER stress-related signaling pathways.

Effect of garlic oil and fish on glucocorticoid-induced osteoporosis in rats

Effect of garlic oil and fish on glucocorticoid-induced osteoporosis in rats

Evaluation of the effects of photobiomodulation on vertebras in two rat models of experimental osteoporosis.

The aim of this study was to evaluate the effects of photobiomodulation (PBM) on cancellous bone in rat models of ovariectomized induced osteoporosis (OVX-D) and glucocorticoid-induced osteoporosis (GIOP). The experiment comprised of nine groups. A group of healthy rats was used for baseline evaluations. The OVX-D rats were further divided into groups as follows: control rats with osteoporosis, OVX-D rats that received alendronate (1mg/kg 60days), OVX-D rats treated with pulsed wave laser (890nm, 80Hz, 900s, 0.0061W/cm2, 5.5J/cm2, three times a week, 60days), and OVX-D rats treated with alendronate + pulsed laser. Dexamethasone was administered to the remaining rats that were split into four groups: control, alendronate-treated rats, laser-treated rats, and GIOP rats treated with alendronate + laser. T12, L1, L2, and L3 vertebrae were subjected to laser. Results of the current study demonstrated that OVX-D and GIOP significantly decreased some stereological parameters, and type 1 collagen gene expression compared to the healthy group. There was a significant increase in osteoclast number in both OVX-D and glucocorticoid administration compared to the healthy group. However, the detrimental effect of the OVX-D procedure on bone was more serious than glucocorticoid administration. Results showed that laser alone had a detrimental effect on trabecular bone volume, and cortical bone volume in groups GIOP and OVX-D compared to those in the healthy group. Alendronate significantly improved total vertebral bone volume, trabecular bone volume, and cortical bone volume, in GIOP and OVX-D groups compared to the laser-treated groups. Furthermore, the alendronate + laser in OVX-D rats and GIOP rats produced significantly increased osteoblast number and type 1 collagen gene expression and caused a significant decrease in osteoclast number compared to the controls.

Preventive effects of Polygonum multiflorum on glucocorticoid-induced osteoporosis in rats.

In Traditional Chinese Medicine, Polygonum multiflorum (PM) is known for its anti-aging properties. A previous study by our group showed that extracts of PM were able to prevent and treat bone loss in vivo, and the active components emodin and 2,3,5,4,-tetrahydroxystilbene-2-O-β-glucoside (TSG) promoted the osteogenic differentiation of mesenchymal stem cells in vitro. The aim of the present study was to investigate the preventive effects of PM on glucocorticoid-induced osteoporosis (GIO) in rats. A crude extract of PM was prepared with 75% ethanol, purified and enriched using a D-101 macroresin column and elution with 30% ethanol, and the material obtained was assessed by high-performance liquid chromatography. Male or female Sprague Dawley rats (n=180) were randomly divided into nine groups: Control, prednisone, prednisone plus calcitriol (CAL), prednisone plus 30% ethanolic eluate of PM [high (H), medium (M) and low (L) dose] and prednisone plus crude extract of PM (H, M and L dose). Prednisone was orally administered to the osteoporosis model rats for 21 weeks, alongside which they received PM extracts. The weight of the viscera, anterior tibial muscle and other tissues was recorded at the end of the experiment. The femur and lumbar vertebra were collected for the measurement of three-dimensional microarchitecture by micro-computed tomography scanning, assessment of biomechanical properties and determination of bone mineral density (BMD). In the 30% ethanolic eluate of the PM extract, the content of TSG and combined anthraquinone was 9.20 and 0.15%, respectively, and that in the crude extract of PM was 2.23 and 0.03%, respectively. Over 6 weeks, the weight of the rats the in prednisone group decreased (P<0.05), while the weight of rats treated with M and H doses of 30% ethanolic eluate was increased compared with that in the prednisone group (P<0.05). Rats exposed to prednisone exhibited a deteriorated bone microarchitecture, low BMD, decreased bone volume/total volume and poor biomechanical properties. Furthermore, the weight of the adrenal gland and the anterior tibial muscle was decreased. 30% ethanolic eluate of PM at M and L doses and crude extract of PM at the H dose counteracted the alterations of skeletal and other characteristics induced by prednisone in rats, as did CAL. In conclusion, extracts of PM exerted a protective effect on bone tissue in GIO rats.

Effects of the combined Herba Epimedii and Fructus Ligustri Lucidi on bone turnover and TGF-β1/Smads pathway in GIOP rats

Ethnopharmacological relevanceKidney deficiency is the main pathogenesis of osteoporosis based on the theory of “kidney governing bones” in traditional Chinese medicine (TCM). Combined Herba Epimedii and Fructus Ligustri Lucidi, based on traditional Chinese formula Er-Zhi pills, were frequently used in TCM formulas that were prescribed for kidney tonifying and bone strengthening. However, it is unclear whether the combination of the two herbs may have a protective influence on glucocorticoid-induced osteoporosis (GIOP). The objective of this study was to evaluate the therapeutic effects and the underlying molecular mechanism of the decoction and the active fractions of the combined herbs in GIOP rats. Materials and methodsMale Sprague-Dawley rats were divided into seven groups, including the normal control (NC), GIOP model (MO), active fractions low (100mg/kg, LAF), active fractions high (200mg/kg, HAF), decoction low (3.5g/kg, LD), decoction high (7g/kg, HD) and Calcium with Vitamin D3 (0.2773g/kg, CaD)-treated group. The GIOP model was established by intramuscular injection of dexamethasone (1mg/kg) twice a week for 8 weeks. Different kinds of indicators were measured, including bone mineral density (BMD), bone biomechanical properties, serum bone alkaline phosphatase (b-ALP), serum bone γ-carboxyglutamic acid-containing protein (BGP), serum bone morphogenetic protein-2 (BMP-2), serum tartrate-resistant acid phosphatase (TRACP) and serum carboxy terminal cross linked telopeptide of typeⅠcollagen (ICTP), bone mineral content (BMC) and bone structured histomorphometry. The protein and mRNA expression of TGF-β1, Smad2, Smad3, Smad4 and Smad7 were detected by Western blotting (WB) and quantitative real time polymerase chain reaction (qRT-PCR), respectively. ResultsAdministration of combined Herba Epimedii and Fructus Ligustri Lucidi decoction and combined active fractions could significantly prevent GC-induced bone loss by increasing the contents of serum b-ALP, BGP and BMP-2 as the markers of bone formation, reducing the serum TRACP and ICTP contents to inhibit bone resorption and enhancing BMC. They could also attenuate biomechanical properties and BMD reduction, deterioration of trabecular architecture in MO rats. The mRNA and protein expressions of TGF-β1, smad2, smad3 and smad4 were up-regulated, and the mRNA and protein expression of Smad7 was down-regulated following combined Herba Epimedii and Fructus Ligustri Lucidi treatment. ConclusionCombination of Herba Epimedii and Fructus Ligustri Lucidi exhibited protective effects on promoting bone formation and precluding bone resorption. The underlying mechanism may be attributed to its regulations on TGF-β1/Smads pathway. The substance bases of the combined herbs on anti-osteoporosis were total flavonoids of Herba Epimedii, total iridoids and flavonoids of Fructus Ligustri Lucidi.

Tetramethylpyrazine Protects Against Glucocorticoid-Induced Apoptosis by Promoting Autophagy in Mesenchymal Stem Cells and Improves Bone Mass in Glucocorticoid-Induced Osteoporosis Rats.

Glucocorticoid-induced osteoporosis (GIOP) is a widespread clinical complication due to the common use of glucocorticoids. Excess glucocorticoids induce apoptosis of bone marrow-derived mesenchymal stem cells (BMSCs), which have been shown to play an increasingly important role in the pathogenesis and therapy of osteoporosis. Tetramethylpyrazine (TMP), an extract from one of the most recognized herbs in traditional Chinese medicine (Chuanxiong), has been reported to have antiapoptotic properties. In this study, we tested whether TMP protects rat BMSCs following exposure to glucocorticoids in vitro and in vivo. We treated BMSCs with different concentrations of TMP (50, 100, or 200 μM) and exposed them to 10-6 M dexamethasone (Dex) for 48 h in vitro. Our data showed that TMP inhibited Dex-induced cytotoxicity and protected BMSCs from apoptosis. Interestingly, further results demonstrated that TMP prevented apoptosis in BMSCs by promoting autophagy in an AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) pathway-dependent manner. In addition, calcein fluorescence double labeling and microcomputed tomography scanning indicated that 12 weeks of TMP administration augmented bone formation and protected trabecular bone mass in GIOP rats. We also discovered that first-passage BMSCs isolated from the TMP treatment group had a lower rate of apoptosis and a higher light chain 3 (LC3)-II/LC3-I ratio than the GIOP group. Our findings demonstrate for the first time that TMP can protect BMSCs from exposure to excess glucocorticoids by promoting autophagy through AMPK/mTOR pathway and might be an effective agent for the prevention and treatment of GIOP.

1H NMR-based metabonomic study on the effects of Epimedium on glucocorticoid-induced osteoporosis.

Glucocorticoids are widely used in clinical practice for the treatment of many immune-mediated and inflammatory diseases, and glucocorticoid-induced osteoporosis (GIO) is the most common type of secondary osteoporosis. Epimedium is one of the most commonly used traditional Chinese medicines for treating osteoporosis. In the present study, we systematically analysed the metabonomic characteristics of GIO model rats and elucidated the therapeutic effect of Epimedium by using a 1H NMR-based metabonomic approach in conjunction with multivariate data analysis. Rats in treatment and model groups were injected with dexamethasone (0.1mg/kg/day) for 5 weeks. Simultaneously, two treatment groups were orally administered Epimedium (10g/kg/day) or Alendronate (1.2mg/kg/day) for 5 weeks. In GIO model rats, lipid and lactate levels in serum were increased, while creatine/creatinine, PC/GPC, taurine, glycine and β-glucose levels were decreased. In urine, GIO rats had higher levels of phenylacetylglycine but lower levels of 2-oxoglutarate, citrate, creatine/creatinine, taurine, PC/GPC and hippurate than controls. Epimedium reversed the aforementioned metabolic alterations in multiple metabolic pathways involved in energy, lipid, amino acid and phospholipid metabolism and gut microbiota derangement. Our results indicated that Epimedium had significant effects in the prevention and treatment of osteoporosis. It is concluded that 1H NMR metabonomics is a useful method for studying the metabolic effects of traditional Chinese medicine from a systematic and holistic view.

Tetramethylpyrazine protects against apoptosis through promoting autophagy in mesenchymal stem cells and improves bone mass in glucocorticoid-induced osteoporosis rats

Tetramethylpyrazine protects against apoptosis through promoting autophagy in mesenchymal stem cells and improves bone mass in glucocorticoid-induced osteoporosis rats

Vanadate Impedes Adipogenesis in Mesenchymal Stem Cells Derived from Different Depots within Bone.

Glucocorticoid-induced osteoporosis (GIO) is associated with an increase in bone marrow adiposity, which skews the differentiation of mesenchymal stem cell (MSC) progenitors away from osteoblastogenesis and toward adipogenesis. We have previously found that vanadate, a non-specific protein tyrosine phosphatase inhibitor, prevents GIO in rats, but it was unclear whether vanadate directly influenced adipogenesis in bone-derived MSCs. For the present study, we investigated the effect of vanadate on adipogenesis in primary rat MSCs derived from bone marrow (bmMSCs) and from the proximal end of the femur (pfMSCs). By passage 3 after isolation, both cell populations expressed the MSC cell surface markers CD90 and CD106, but not the hematopoietic marker CD45. However, although variable, expression of the fibroblast marker CD26 was higher in pfMSCs than in bmMSCs. Differentiation studies using osteogenic and adipogenic induction media (OM and AM, respectively) demonstrated that pfMSCs rapidly accumulated lipid droplets within 1 week of exposure to AM, while bmMSCs isolated from the same femur only formed lipid droplets after 3 weeks of AM treatment. Conversely, pfMSCs exposed to OM produced mineralized extracellular matrix (ECM) after 3 weeks, compared to 1 week for OM-treated bmMSCs. Vanadate (10 μM) added to AM resulted in a significant reduction in AM-induced intracellular lipid accumulation and expression of adipogenic gene markers (PPARγ2, aP2, adipsin) in both pfMSCs and bmMSCs. Pharmacological concentrations of glucocorticoids (1 μM) alone did not induce lipid accumulation in either bmMSCs or pfMSCs, but resulted in significant cell death in pfMSCs. Our findings demonstrate the existence of at least two fundamentally different MSC depots within the femur and highlights the presence of MSCs capable of rapid adipogenesis within the proximal femur, an area prone to osteoporotic fractures. In addition, our results suggest that the increased bone marrow adiposity observed in GIO may not be solely due to direct effect of glucocorticoids on bone-derived MSCs, and that an increase in femur lipid content may also arise from increased adipogenesis in MSCs residing outside of the bone marrow niche.

Effect of glucocorticoid withdrawal on glucocorticoid inducing bone impairment

Glucocorticoid (GC) withdrawal after a short-term use was common in clinical practice like immediate post-transplant period. However, previous studies without setting age-control group failed to determine whether the BMD recovery was sufficient and whether it is necessary to accept anti-osteoporosis therapy after GC withdrawal. The aim of this study was to investigate the effect of GC withdrawal on bone impairment in glucocorticoid-induced osteoporosis (GIOP) rats. Twenty-four female Sprague-Dawley rats (3 months’ old) were randomly divided into two treatment groups: an untreated age-control group (Con, n = 12); another group receiving a dexamethasone injection (DEXA, n = 12). Animals in the Con group were euthanized at 3rd month (M3) and 6th month (M6), respectively. Six rats in the DEXA group were euthanized at 3rd month (M3), whereas GC intervention was withdrew in the remaining animals of DEXA group, which were euthanized at the end of 6th month (M6). Bone mass, bone microarchitecture, biomechanical properties of vertebrae, morphology, serum levels of PINP and β-CTX were evaluated. Compared with the Con(M3) group, the Con(M6) group showed significantly better bone quantity, morphology and quality. Compared with the Con(M3) group, the DEXA (M3) group showed significantly lower BMC, BMD, BS/TV, BV/TV, Tb.N, Tb.Th, vBMD, bone strength, compressive displacement, energy absorption capacity, PINP levels, β-CTX levels, and damaged trabecular morphology. And the same change trend was observed in the comparison between the Con(M6) group and DEXA (M6) group. Compared with the DEXA (M3) group, the DEXA (M6) group showed significantly higher BMC, BMD and AREA, but no significant difference in BS/TV, BV/TV, SMI, Tb.N, Tb.Th, Tb.Sp, vBMD, bone strength, bone stiffness, compressive displacement, energy absorption capacity, PINP levels, β-CTX levels, and improvement in trabecular morphology was observed. These results indicate that the reverse effect of GC withdrawal for 3 months on bone impairment in GIOP rats was insufficient, which implied that related anti-osteoporosis treatment might be still necessitated after GC withdrawal in clinical setting.

Ginsenosides Rg3 attenuates glucocorticoid-induced osteoporosis through regulating BMP-2/BMPR1A/Runx2 signaling pathway

Glucocorticoid-induced osteoporosis (GIOP) is the primary cause of secondary osteoporosis and the existing therapeutic strategies are limited. The aim of this study is to evaluate the effects of ginsenosides (GS) Rg3 on dexamethasone (DEX)-induced osteoporosis in vivo and in vitro. GIOP rat was established by DEX injection for 5 weeks and treated by GS Rg3 10 or 20 mg/kg. Body weight and bone mineral density (BMD) of rats were measured at the beginning and the end of the experiment. Histological changes of femurs were observed using HE staining. The in vitro model was established on primary osteoblasts induced by DEX. CCK-8 assay was used to test the cell viability. Bone metabolism markers in serum or primary osteoblasts were detected using biochemical kits. Real time PCR and western blot were used to measure nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), bone morphogenic protein-2 (BMP-2), BMP receptor 1A (BMPR1A) and Runx2 expression. The results demonstrated that GS Rg3 prevented DEX-induced body weight and BMD reduction, enhanced secretion of bone formation markers and decreased bone resorption markers. In addition, GS Rg3 was found to prevent the suppression of BMP-2/BMPR1A/Runx2 signals induced by DEX both in GIOP rats and primary osteoblasts. Inhibition of BMP-2 by noggin completely blocked the bone-alkaline phosphatase-secretion-promoted effect of GS Rg3 in vitro. These data suggest that GS Rg3 attenuates GIOP through regulating BMP-2 signaling pathway. This study provides a potential drug candidate for GIOP therapy.

Antiosteoporotic effect of Petroselinum crispum, Ocimum basilicum and Cichorium intybus L. in glucocorticoid-induced osteoporosis in rats.

BackgroundGlucocorticoid-induced osteoporosis (GIO) is one of the serious side effects which have become the most common secondary osteoporosis. The purpose of this study is to evaluate the effect of aqueous extract of parsley, basil and chicory on glucocorticoid-induced osteoporosis in rats.MethodsFifty Female rats were divided into five groups and treated for 8 weeks as follow: group 1 served as control; group (2) subcutaneously injected with 0.1 mg/kg b. wt. dexamethasone dissolved in saline; group 3 received similar dose of dexamethasone together with aqueous parsley extract in a dose of 2 g/kg b. wt.; group 4 received similar dose of dexamethasone together with 400 mg/kg b. wt. aqueous basil extract and group 5 received similar dose of dexamethasone together with 100 mg/kg b. wt. aqueous chicory extract.ResultsThe dexamethasone group showed a significant decrease in serum E2, Ca, P levels and significant decrease in total BMD, BMC and a significant increase in serum PTH, ALP and ACP. Bone TBARs was significantly increased while GSH, antioxidant enzymes were significantly decreased. These changes were attenuated by parsley, basil and chicory extracts in the group 3, 4 and 5 respectively.ConclusionAqueous extracts of parsley, basil and chicory showed bone protection against glucocorticoid-induced in rats. From our results, we concluded that chicory has a potent protective effect more than parsley and basil due to containing flavonoids and inulin.

The in vivo effects of a fraction from Dioscorea spongiosa on glucocorticoid-induced osteoporosis

Ethnopharmacological relevanceIn traditional Chinese medicines, osteoporosis was considered to be induced by the deficiency of kidney's function. The Rhizoma of Dioscorea spongiosa was one of the kidney tonifying and bone strengthening agent in the traditional usage and previous study had shown that its 90% ethanol fraction was effective on anti-osteoporosis using the ovariectomized (OVX) rats. However, for the secondary osteoporosis, like glucocorticoid-induced osteoporosis (GIO), its effect was still unknown. Materials and methodsThe GIO model was established by injecting dexamethasone into the muscles of rats. The 90% ethanol extraction of Dioscorea spongiosa (DSE) were administrated to rats in three different dosages, 125, 250 and 500mg/Kg/d, respectively. After the administration, the rats were sacrificed to measure different kinds of indicators, including the biochemical indexes in urine and serum, the bone tissue metrology, BMC and BMD, biomechanical indicators and histological changes. ResultsDSE could significantly reduce the content of BGP, ALT, TRAcP, HOP/Cr and Ca/Cr, increase the content of P/Cr compared with the control group, suggesting that DSE is effective on controlling the excessive transition of bones and inhibiting the bone resorption. By the administration of DSE, the dry bone weight/volume, ash weight/volume, the content of Ca, BMD and BMC were also obviously increased, suggesting that DSE could increase the bone mass by increasing its Ca content. Besides, the flexure strength and maximum bending force could be improved by DSE, suggesting that it could strengthen the hardness and strength of bones. In the histological investigation, DSE could repair the broken of cancellous bones and bone trabecular with the similar activity with XLGB. ConclusionsThe results showed that DSE is effective on inhibiting GIO in rats by improving the bone tissue metrology, BMC and BMD as well as biomechanical indicators, and also repairing the microscopic changes of cancellous bones and trabecular bones. The mechanism was related to the inhibition of excessive bone transition and bone resorption according to the changes of biochemical indexes.

Curcumin alleviates glucocorticoid-induced osteoporosis by protecting osteoblasts from apoptosis in vivo and in vitro.

Curcumin, an active component of the rhizomes of Curcumin longa L., possesses broad anti-inflammation and anti-cancer properties. Curcumin was previously reported to be capable of protecting ovariectomized rats against osteoporosis. However, the effect of curcumin on glucocorticoid-induced osteoporosis (GIO) is not yet clear. The present study investigated the effects of curcumin on dexamethasone (Dex)-induced osteoporosis in vivo and Dex-induced osteoblast apoptosis in vivo and in vitro. The GIO rat model was induced by subcutaneous injection of Dex for 60 days and verified to be successful as evidenced by the significantly decreased bone mineral density (BMD) determined using dual X-ray absorptiometry. Subsequently, curcumin administration (100 mg/kg) for 60 days obviously increased BMD and bone-alkaline phosphatase, decreased carboxy-terminal collagen cross links, enhanced bone mechanical strength, and improved trabecular microstructure, thereby alleviating Dex-induced osteoporosis. Mechanically, curcumin remarkably reversed Dex-induced femoral osteoblast apoptosis in vivo. In cultured primary osteoblasts, pretreatment with curcumin concentration-dependently decreased the number of Dex-induced apoptotic osteoblasts by down-regulating the ratio of Bax/Bcl-2 as well as the levels of cleaved caspase-3 and cleaved poly ADP-ribose polymerase (PARP). Moreover, curcumin pretreatment activated extracellular signal regulated kinase (ERK) signalling in Dex-induced osteoblasts by up-regulating the expression level of p-ERK1/2. Taken together, our study demonstrated that curcumin could ameliorate GIO by protecting osteoblasts from apoptosis, which was possibly related to the activation of the ERK pathway. The results suggest that curcumin may be a promising drug for prevention and treatment of GIO.

An experimental study to evaluate the antiosteoporotic effect of Panchatikta Ghrita in a steroid-induced osteoporosis rat model

Objective:The study was conducted to develop the glucocorticoid-induced osteoporosis (GIO) model in Sprague-Dawley weanling rats using different doses of methylprednisolone (MP) and evaluate the antiosteoporotic effect of a classical ayurvedic formulation, Panchatikta Ghrita (PG), in this model.Materials and Methods:Institutional Animal Ethics Committee approval was obtained. Development of model was done by subcutaneous injection of 2 doses of MP (14 and 28 mg/kg/week) for 4 weeks in 21-day old weanlings. Following confirmation of the dose of MP that induced osteoporosis, the antiosteoporotic effect of PG was tested in this model in comparison to a known antiosteoporotic agent, alendronate. Both alendronate (2.9 mg/kg/day) and PG (1.35 g/kg/day) were administered orally 2 weeks after MP - 14 mg/kg/week injection and continued for 4 weeks. Serum and urine calcium and inorganic phosphate were analyzed at weekly intervals. Animals were sacrificed after 6 weeks, and femur bones were processed to measure bone hardness and elasticity and for histological studies.Results:Rats treated with MP - 14 mg/kg/week showed optimum osteoporotic effect with no mortality as compared to MP - 28 mg/kg/week; hence, this dose of MP was used further for the efficacy study. Osteoporotic rats treated with PG 1.35 g/kg showed increase in serum calcium and inorganic phosphate levels, whereas urine calcium and phosphate levels were significantly reduced. A significant decrease in a number of osteoclasts, whereas an increase in bone hardness and elasticity was observed as compared to diseased group demonstrating antiosteoporotic effect of PG.Conclusion:PG has an antiosteoporotic effect in GIO rat model.

Effect of Pulsed Electromagnetic Field on Bone Formation and Lipid Metabolism of Glucocorticoid-Induced Osteoporosis Rats through Canonical Wnt Signaling Pathway.

Pulsed electromagnetic field (PEMF) has been suggested as a promising method alternative to drug-based therapies for treating osteoporosis (OP), but the role of PEMF in GIOP animal models still remains unknown. This study was performed to investigate the effect of PEMF on bone formation and lipid metabolism and further explored the several important components and targets of canonical Wnt signaling pathway in GIOP rats. After 12 weeks of intervention, bone mineral density (BMD) level of the whole body increased significantly, serum lipid levels decreased significantly, and trabeculae were thicker in GIOP rats of PEMF group. PEMF stimulation upregulated the mRNA and protein expression of Wnt10b, LRP5, β-catenin, OPG, and Runx2 and downregulated Axin2, PPAR-γ, C/EBPα, FABP4, and Dkk-1. The results of this study suggested that PEMF stimulation can prevent bone loss and improve lipid metabolism disorders in GIOP rats. Canonical Wnt signaling pathway plays an important role in bone formation and lipid metabolism during PEMF stimulation.

Prevention of Radix Rehmanniae Preparata on Glucocorticoid-Induced Osteoporosis in Rats

The aim of present study is investigating the preventive effects of Radix Rehmanniae Preparata (PPR) on glucocoroticoids-induced osteoporosis rats. Forty-eight 3-month SD rats were divided into baseline (BAS) group, age control (CON) group, and glucocorticoids group. The glucocorticoids group were further divided into GC group (n=8) treated with glucocorticoids only, GC+ CaD group was given glucocorticoids plus calcium carbonate (375 mg·kg-1·d-1 oral) and vitamin D3 50 U/kg per day oral; GC+ low dose RRP group were treated with glucocoroticoids plus PPR (4 ml·kg-1·d-1 oral); GC+ high dose RRP group were treated with glucocoroticoids plus PPR (7.5 ml·kg-1·d-1oral). After 24 weeks of treatment, the rats were sacrificed under sterile conditions. The right tibiae were removed for bone histomorphometry, and the right femurs were stored for bone biomechanics testing. In GC group, body weight, Alkaline phosphatase (ALP), C-terminal propeptide of type I procollagen (PICP), were increased.% Tb.Ar, Tb.Wi, Tb.N and modulus of rigidity indices decrease significantly and Tb.Sp indices increased significantly in GC group compared with the CON group, while RRP and calcium carbonate with vitamin D3 can prevented the decreased in bone histomorphometry and biomechanical quality. The present results suggest that RRP prevent glucocorticoid-induced osteoporosis by improving bone formation.

Synthesis of a novel class of substituted benzothiophene or benzofuran derivatives as BMP-2 up-regulators and evaluation of the BMP-2-up-regulating effects in vitro and the effects on glucocorticoid-induced osteoporosis in rats

The BMP pathway is a promising new target for the design of therapeutic agents for the treatment of low bone mass. To enrich our understanding of SAR and based on our previously concluded structure–effect relationship, 23 derivatives were prepared in this work. The synthesis, up-regulating activities on BMP-2 expression, and bone loss prevention efficacies of these compounds in rats with glucocorticoid-induced osteoporosis are presented. The bone histology of the tested rats assessed through light microscopy showed that compounds 1, 21, 35, and 38 significantly increased the trabecula compared with the model group, and the trabecula of the groups treated with 8a was similar to that obtained with raloxifene and alfacalcidol. The compounds exhibited potential for development as anabolic agents.