Metabolomics and pharmacodynamic analysis unveil the therapeutic role of icaritin on osteoporosis rats

Osteoporosis is a systemic metabolic bone disease characterized by a reduction in bone mass resulting from multifactorial causes. Icaritin (ICT), a flavonoid glycoside, exhibits a multitude of effects on bone tissue. To examine the influence of ICT on bone trabecular loss in vivo, ovariectomized (OVX) rats were utilized. The ability of ICT to mitigate bone trabecular loss and the underlying anti-osteoporotic pathways were assessed using ovariectomy-induced osteoporosis rats. Furthermore, we gain insights into the osteoprotective mechanisms of ICT on osteoporosis by conducting UPLC-Orbitrap-MS-based metabolomics of rat urine. The results of experiments demonstrated a significant attenuation of bone trabecular loss, as well as improvements in biochemical indices, biomechanical parameters, and microstructure in the ICT administered group compared to the OVX group. Moreover, metabolomics results suggested that the ICT treatment adjusted 33 different metabolites, which associated with the metabolism of amino acids, lipids, and energy. The findings suggest that the anti-osteoporosis effect of ICT may be related to the activation of PI3K/AKT signal and the inhibition of TLR4 pathway regulated by metabonomics. These results contribute to a better understanding of the therapeutic potential of ICT in the treatment of osteoporosis.

MEDAG expression in vitro and paeoniflorin alleviates bone loss by regulating the MEDAG/AMPK/PPARγ signaling pathway in vivo

Objectives

Osteoporosis (OP) is characterized by reduced bone mass and impaired bone microstructure. Paeoniflorin (PF) is isolated from peony root with anti-inflammatory, immunomodulatory, and bone-protective effects. Up to now, the mechanism of anti-OP in PF has not been completely clarified.

Methods

The expression of MEDAG in osteoclasts, osteoblasts and adipocytes was detected by RT-qPCR. The OVX mouse model was constructed, and oral administration of PF was performed for 15 weeks. Bone microstructure was detected by H&E staining and a micro-CT system, and expression of signaling proteins examined by Western blot and immunohistochemical staining. ELISA and biochemical kits were used to quantify serum metabolite levels.

Key findings

MEDAG were upregulated in osteoclasts and adipocytes, and downregulated in osteoblasts. PF administration effectively alleviated OVX-induced bone loss, and histological changes in femur tissues. Moreover, PF significantly reduced serum TRAP, CTX-1, P1NP, BALP, and LDL-C levels and increased HDL-C. In addition, PF inhibited the expression of MEDAG, cathepsin K, NFATc1, PPARγ, and C/EBPα and increased p-AMPKα, OPG and Runx2.

Conclusions

MEDAG is a potential target for bone diseases, and PF might attenuate OVX-induced osteoporosis via MEDAG/AMPK/PPARγ signaling pathway.

Cognitive enhancing effects of pazopanib in D‑galactose/ovariectomized Alzheimer's rat model: insights into the role of RIPK1/RIPK3/MLKL necroptosis signaling pathway

Necroptosis, a programmed form of necrotic cell death carried out by receptor-interacting serine/threonine protein kinase 1 (RIPK1) and RIPK3, has been found to be implicated in the pathogenesis of Alzheimer's disease (AD). An FDA-approved anti-cancer drug, pazopanib, is reported to possess potent inhibitory effect against necroptosis via interfering with RIPK1. So far, there are no existing data on the influence of pazopanib on necroptotic pathway in AD. Thus, this study was designed to explore the impact of pazopanib on cognitive impairment provoked by ovariectomy (OVX) together with D-galactose (D-Gal) administration in rats and to scrutinize the putative signaling pathways underlying pazopanib-induced effects. Animals were allocated into four groups; the first and second groups were exposed to sham operation and administered normal saline and pazopanib (5 mg/kg/day, i.p.), respectively, for 6 weeks, while the third and fourth groups underwent OVX then were injected with D-Gal (150 mg/kg/day, i.p.); concomitantly with pazopanib in the fourth group for 6 weeks. Pazopanib ameliorated cognitive deficits as manifested by improved performance in the Morris water maze besides reversing the histological abnormalities. Pazopanib produced a significant decline in p-Tau and amyloid beta (Aβ) plaques. The neuroprotective effect of pazopanib was revealed by hampering neuroinflammation, mitigating neuronal death and suppressing RIPK1/RIPK3/MLKL necroptosis signaling pathway. Accordingly, hindering neuroinflammation and the necroptotic RIPK1/RIPK3/MLKL pathway could contribute to the neuroprotective effect of pazopanib in D-Gal/OVX rat model. Therefore, this study reveals pazopanib as a valuable therapeutic agent in AD that warrants future inspection to provide further data regarding its neuroprotective effect.

The bone-protective benefits of amino-conjugated calcium in an ovariectomized (OVX) rat model

Low bone density, fragility, and microarchitectural disintegration are the symptoms of osteoporosis. An imbalance between bone growth and resorption can lead to osteoporosis. This study evaluated the effects of amino-calcium (AC) on bone protection in ovariectomized control group (NC) rats. Amino-calcium (AC) was characterized using Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and nuclear magnetic resonance spectroscopy analyses (NMR). After determining the biocompatibility of amino-calcium (AC) with MC3T3-E1 cells, alkaline phosphatase staining revealed significant changes on day 7. Three of the four groups underwent ovariectomy, whereas one group received a placebo. On micro-computed tomography, in vivo, data showed increased bone volume fraction in the femoral head and shaft areas in the amino-calcium (AC) group. Hematoxylin and eosin staining showed a bone mass and architectural protection in the amino-calcium (AC) group compared with the calcium carbonate and OVX control group. RNA sequencing analysis revealed high expression of osteogenesis-related genes in MC3T3-E1 cells. RNA sequencing revealed a significant fold change in the expression of integrin-binding sialoprotein (IBSP), bone gamma-carboxyglutamate proteins 1 and 2(BGLAP1 and BGLAP2), and periostin (POSTN). The study concluded that supplementing the OVX rats with calcium enhanced bone protection.

Ellagic acid inhibits CDK12 to increase osteoblast differentiation and alleviate osteoporosis in hindlimb-unloaded and ovariectomized mice

BACKGROUND

Osteoporosis is a highly prevalent bone disease occurred commonly in astronauts and postmenopausal women due to mechanical unloading and estrogen deficiency, respectively. At present, there are some traditional Chinese medicine compounds for preventing and treating osteoporosis induced by simulated microgravity, but the detailed components of the traditional Chinese medicines still need to be confirmed and osteoporosis is still untreatable due to a lack of effective small-molecule natural medicine.

PURPOSE

To explore the role of cyclin-dependent kinase 12 (CDK12) in osteoporosis induced by simulated microgravity and the therapeutic effect of CDK12-targeted Ellagic Acid (EA) on osteoporosis.

METHODS

Our previous study has suggested that CDK12 as a potential target for treating and preventing osteoporosis. In this study, the role of CDK12 in osteoblasts and mice bone tissues was further studied under simulated microgravity. And by targeting CDK12, natural small-molecule product EA was screened out based on a large scale through the weighted set similarity (WES) method and the therapeutic effects of EA on osteoporosis was investigated in hindlimb-unloaded (HU) mouse model and ovariectomized (OVX) model.

RESULTS

The results demonstrated that simulated microgravity inhibited bone formation and up-regulated the expression of CDK12. Furthermore, CDK12-siRNA or THZ531 (an inhibitor of CDK 12) promoted osteoblast differentiation, while the overexpression of CDK12 inhibited osteoblasts differentiation. And we further proved that CDK12-targeted EA showed a rescue effect on osteoblast differentiation inhibition caused by simulated microgravity. EA (50 mg·kg^-1·day^-1) daily intragastric administration alleviated the symptoms of osteoporosis and accompanied with the improvement of trabecular bone and cortical bone parameters with significantly overexpression of CDK12.

CONCLUSION

EA efficiently improves osteoporosis by targeting CDK12, which is a suppresser of osteoblast differentiation and a novel therapeutic target for treating osteoporosis.

Genistein and exercise treatment reduced NASH related HDAC3, IL-13 and MMP-12 expressions in ovariectomized rats fed with high fat high fructose diet

Background and aim

Genistein (GEN) and exercise (Ex) may be regarded as an alternative treatment for non-alcoholic steatohepatitis (NASH). However, the mechanisms behind their therapeutic effects in NASH are not well-understood.

Experimental procedure

This study investigated the roles of histone deacetylase (HDAC)3 and interleukin-(IL-)13 in the NASH model of ovariectomized (OVX) rats fed with high fat high fructose (HFHF) diet.

Results and conclusion

Nine weeks after being fed with HFHF diet, severe NASH pathology with mild fibrosis were seen along with an increase in HDAC3, IL-13 and matrix metalloelastase (MMP-12) expressions in OVX rats. Five weeks of either GEN or Ex treatments abrogated the increase in both HDAC3 and IL-13 expressions in OVX rats fed with HFHF diet and ameliorated NASH features, liver fibrosis and MMP-12 expression. The combination of Gen and Ex, however, did not provide additional benefits on NASH features in OVX rats fed with HFHF diet. These results suggested that GEN and Ex treatments improved HFHF diet induced NASH in OVX rats through the suppression of HDAC3, IL-13 and MMP-12 expression.

•Estrogen deficiency leads to NASH development.

•Either genistein or exercise modulated lipid metabolism reducing steatohepatitis.

•Either genistein or exercise attenuated liver fibrosis improving NASH.

•Combining genistein and exercise did not provide additional benefits.

•Genistein and exercise have beneficial effects in post-menopausal women with NASH.

Effect of white tea consumption on serum leptin, TNF-α and UCP1 gene expression in ovariectomized rats

BACKGROUND

Obesity and dyslipidemia due to estrogen deficiency are among the important health problems in menopausal women. Increasing evidence reports the anti-obesity and anti-hyperlipidemic properties of tea polyphenols. However, the effect of white tea (WT) with high polyphenol content on overweight and lipid profile is uncertain. Here, we aimed to examine the effects of long-term WT consumption on serum leptin, tumor necrosis factor- alpha (TNF-α) and uncoupling protein 1 (UCP1) mRNA gene expression in ovariectomized (OVX) rats.

METHODS

Adult rats were divided into four groups (n = 8): (i) sham, (ii) OVX, (iii) WT and (iv) OVX + WT. WT was given at a dose of 0.5% w/v for 12 weeks. In the study, body weight, serum leptin, TNF, estradiol (E2) levels, lipid profile and UCP1 mRNA gene expression in brown adipose tissue (BAT) were evaluated.

RESULTS

There was a significant increase in body weight of OVX rats, which was decreased following WT consumption. While leptin and E2 levels decreased in the OVX group, TNF levels increased. There was no difference between the NF-kB levels of the groups. In addition, BAT UCP1 mRNA expression was significantly decreased in OVX groups, while WT treatment stimulated UCP1 activity.

CONCLUSION

We explain the stimulatory effect of WT on weight loss mainly by the induction of UCP1 gene-mediated thermogenesis and suppression of inflammation. Therefore, we suggest that prolonged WT consumption may have beneficial effects in limiting excess weight gain caused by estrogen deficiency.

The impact of ovariectomy and chronic estrogen treatment on gene expression in the rat cortex: Implications for psychiatric disorders

Estrogens, via estrogen-mediated changes in CNS function, have been suggested to be beneficial in the treatment of several psychiatric disorders. Few studies have used transcriptomic technologies to determine the effect of estrogen on gene expression in the CNS. Thus, we aimed to examine the impact of ovariectomy (the removal of all ovarian hormones) and estrogen replacement on rat frontal cortical gene expression. We used the Agilent SurePrint G3 Gene Expression Rat Array to measure levels of RNA in intact (cycling) female rats and in ovariectomized rats that were, or were not, given 17β-estradiol in implants for 4 weeks. Compared to untreated ovariectomized rats, intact rats (effect of ovarian hormones; comparison 1) and rats receiving 17β-estradiol replacement (estrogen-specific effects; comparison 2) showed significant changes in cortical gene expression (58 and 36 genes, respectively). These changes in gene expression would be expected to affect pathways that regulate neurotransmitters, glutathione and sphingolipids; pathways known to be implicated in the pathophysiologies of psychiatric disorders. When we compared the levels of gene expression in the two comparisons that had a significance of p < 0.01 independent of magnitude of change, there was a strong correlation between fold changes in gene expression for 127 genes. We posit that this correlation is due to the level of expression of these genes being strongly influenced by both cycling and replacement estrogen. Further exploration of ovarian hormone- and estrogen-sensitive gene expression may provide new insight into the aetiology of aspects of psychiatric disorders that show sex differences.

Bone remodelling in the mouse tibia is spatio-temporally modulated by oestrogen deficiency and external mechanical loading: A combined in vivo/in silico study

Osteoporosis disrupts the healthy remodelling process in bone and affects its mechanical properties. Mechanical loading has been shown to be effective in stimulating bone formation to mitigate initial bone loss. However, no study has investigated the effects of repeated mechanical loading, with a pause of one week in between, in the mouse tibia with oestrogen deficiency. This study uses a combined experimental and computational approach, through longitudinal monitoring with micro-computed tomography, to evaluate the effects of loading on bone adaptation in the tibiae of ovariectomised (OVX) C57BL/6 mice from 14 to 22 weeks of age. Micro-FE models coupled with bone adaptation algorithms were used to estimate changes in local tissue strains due to OVX and mechanical loading, and to quantify the relationship between local strain and remodelling. The first in vivo mechanical loading increased apposition, by 50-150%, while resorption decreased by 50-60%. Both endosteal and periosteal resorption increased despite the second mechanical loading, and periosteal resorption was up to 70% higher than that after the first loading. This was found to correlate with an initial decrease in average strain energy density after the first loading, which was lower and more localised after the second loading. Predictions of bone adaptation showed that between 50 and 90% of the load-induced bone apposition is linearly strain driven at the organ-level, but resorption is more biologically driven at the local level. The results imply that a systematic increase in peak load or loading rate may be required to achieve a similar bone adaptation rate in specific regions of interests.

Metabolomics profiling reveals Echinops latifolius Tausch improves the trabecular micro-architecture of ovariectomized rats mainly via intervening amino acids and glycerophospholipids metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Echinops latifolius Tausch (ELT) is traditional Mongolian medicine in China, and often used to against osteoporosis, strengthen tendons and bones, clear bones heat.

AIM OF THE STUDY

To study efficacy of ELT on ovariectomized (OVX) rats and underly metabolic pathways related to trabecular micro-architecture changing of OVX.

MATERIALS AND METHODS

Three-month-old female Wistar rats were randomly divided into 4 groups (n = 6) including normal group (without surgery), sham group (bilateral laparotomy), OVX group (bilateral ovariectomy), and ELT-treated groups (ELT-treated after bilateral ovariectomy). The effects of ELT on trabecular micro-architecture and biochemical markers of OVX rat were investigated by dual-energy X-ray absorptiometry machine and Enzyme-linked immunosorbent assay (ELISA), respectively. Untargeted metabolomics strategy was applied to discover the potential biomarkers and related metabolic pathways involving the progression of OVX-induced osteoporosis.

RESULTS

The trabecular micro-architecture and biochemical markers of OVX rats were improved by ELT. We found 36 potential biomarkers and 21 related metabolic pathways were involved in progression of OVX-induced osteoporosis. Amino acids metabolism and glycerophospholipids metabolism were mainly intervened in ELT treatment on ovariectomized rats. The disordered amino acids and glycerophospholipids metabolism closely related to the imbalance between bone resorption and formation were reversed by administration of ELT, indicating that the influences of ELT on OVX rats' trabecular micro-architecture may possible be associated with intervening amino acids and glycerophospholipids metabolism.

CONCLUSIONS

This approach may provide the metabolomic perspective to link metabolic alterations and anti-osteoporosis action of ELT, to further explain how ELT works in postmenopausal patients with bone loss.

MiR-1-3p regulates the differentiation of mesenchymal stem cells to prevent osteoporosis by targeting secreted frizzled-related protein 1

Osteoporosis (OP) is a systemic skeletal disorder with the characteristics of bone mass reduction and microarchitecture deterioration, resulting in bone fragility and increased fracture risk. A reduction in the osteoblast-differentiation of bone marrow mesenchymal stem cells (BMSCs) is considered as a basic pathogenesis of osteoporosis. miRNAs play a substantial role in the development and differentiation of BMSCs. In the present study, we found that miR-1-3p was significantly downregulated in the bones of Chinese osteoporotic patients (n = 29). Secreted frizzled-related protein 1 (SFRP1) was predicted as a target gene of miR-1-3p via the TargetScan and PicTar softwares and validated by dual-luciferase reporter assays. The findings revealed that the expression of SFRP1 was inversely correlated with miR-1-3p in osteoporotic patients. We induced mouse MSCs (mMSCs) to osteogenesis or adipogenesis and found that miR-1-3p was upregulated during osteogenesis but downregulated during adipogenesis. The overexpression of miR-1-3p stimulated osteogenesis and inhibited adipogenesis of mMSCs. In addition, ovariectomized (OVX) mice were tested and the function of miR-1-3p in vivo was explored. Immunohistochemistry and histomorphometric assays showed that in vivo inhibition of miR-1-3p increased the expression level of SFRP1 and reduced bone formation and bone mass. Furthermore, tartrate-resistant acid phosphatase (TRAP) staining indicated that the in vivo suppression of miR-1-3p promoted osteoclast activity, suggesting that miR-1-3p may influence bone mass by regulating bone resorption. It can be concluded that miR-1-3p plays a pivotal role in the pathogenesis of osteoporosis via targeting SFRP1 and may be a potential therapeutic target for osteoporosis.

Genistein and exercise modulated lipid peroxidation and improved steatohepatitis in ovariectomized rats

Background

The prevalence of nonalcoholic steatohepatitis (NASH) in menopausal women is increasing, but current treatments have not been proven effective. The objective of this study was to investigate the treatment effects of genistein and running exercise in ovariectomized (OVX) rats with NASH.

Methods

Thirty-six female Sprague-Dawley rats were divided into 6 groups, control; OVX with standard diet; OVX with high fat and high fructose (HFHF) diet for 4 weeks; OVX with HFHF and genistein treatment (16 mg/kg BW/day) for 5 weeks (OVX + HFHF+GEN); OVX with HFHF and moderate intensity exercise for 5 weeks (OVX + HFHF+EX); OVX with HFHF and combined treatments (OVX + HFHF+GEN + EX). Serum interleukin-6 (IL-6) levels, hepatic free fatty acid (FFA), hepatic glutathione (GSH), and hepatic malondialdehyde (MDA) levels were measured. Liver histology was examined to determine NASH severity.

Results

OVX + HFHF group had the highest levels of hepatic FFA compared with OVX and control groups (5.92 ± 0.84 vs. 0.37 ± 0.01 vs. 0.42 ± 0.04 nmol/mg protein, respectively, p < 0.01). Serum IL-6 levels were significantly elevated in both OVX and OVX + HFHF groups as compared with controls (112.13 ± 6.50 vs. 121.47 ± 3.96 vs. 86.13 ± 2.40 pg/mL, respectively, p < 0.01). In OVX + HFHF group, hepatic MDA levels were higher, while GSH levels were lower than in OVX and control groups (MDA; 0.98 ± 0.04 vs. 0.82 ± 0.02 vs. 0.78 ± 0.03 nmol/mg protein, and GSH; 46.01 ± 0.91 vs. 55.21 ± 1.40 vs. 57.94 ± 0.32, respectively; p < 0.01 for both). Comparing with OVX + HFHF group, rats that received genistein, exercise and combined treatments demonstrated an improvement in liver histopathology, decreased levels of hepatic FFA (1.44 ± 0.21 vs. 0.45 ± 0.04 vs. 0.49 ± 0.05 nmol/mg protein, respectively, p < 0.01), serum IL-6 (82.80 ± 2.07 vs. 83.47 ± 2.81 vs. 94.13 ± 1.61 pg/mL, respectively, p < 0.01), and hepatic MDA (0.80 ± 0.03 vs. 0.76 ± 0.02 vs. 0.76 ± 0.03 nmol/mg protein, respectively, p < 0.01).

Conclusions

Genistein and moderate intensity exercise were effective in reducing the severity of NASH in OVX rats through the reduction in liver inflammation, oxidative stress and liver fat contents.

Vitamin K Supplementation Modulates Bone Metabolism and Ultra-Structure of Ovariectomized Mice

BACKGROUND/AIMS

Osteoporosis is a bone metabolic disease that affects mostly post-menopausal women. There has been shown that vitamin K (VK) supplementation during menopause may decrease bone loss as well as risk of bone breaking. Aiming to clarify the beneficial role of VK in bone metabolism during menopause, we investigated mineral metabolism and bone ultrastructure of ovariectomized (OVX) mice.

METHODS

To determine the effects chronic use of VK in bone structure and mineral metabolism in OVX mice, we used several methods, such as DXA, µCTScan, and SEM as well as biomolecular techniques, such as ELISA and qRT-PCR. In addition, complete analysis of serum hormonal and other molecules associated to bone and lipid metabolism were evaluated overview the effects of VK in menopause murine model.

RESULTS

VK treatment significantly affects Pi metabolism independently of OVX, changing Pi plasma, urinary output, balance, and Pi bone mass. Interestingly, VK also increased VLDL in mice independently of castration. In addition, VK increased compact bone mass in OVX mice when we evaluated it by DXA, histomorphometry, µCTScanning. VK increased bone formation markers, osteocalcin, HYP- osteocalcin, and AP whereas it decreased bone resorption markers, such as urinary DPD/creatinine ratio and plasmatic TRAP. Surprisingly, SEM images revealed that VK treatment led to amelioration of microfractures observed in OVX untreated controls. In addition, SHAM operated VK treated mice exhibited higher number of migrating osteoblasts and in situ secretion of AP. OVX led to decreased to in situ secretion of AP that was restored by VK treatment. Moreover, VK treatment increased mRNA expression of bone Calbindin 28KDa independently of OVX.

CONCLUSION

VK treatment in OVX mice exhibited beneficial effects on bone ultrastructure, mostly by altering osteoblastic function and secretion of organic bone matrix. Therefore, VK could be useful to treat osteopenic/osteoporotic patients.

Experimental research into the potential therapeutic effect of GYY4137 on Ovariectomy-induced osteoporosis

BACKGROUND

Evidence has shown that endogenous H2S plays an important role in the physiological and pathophysiological processes of many organs. The study aimed to explore whether exogenous H2S has a potential therapeutic effect on a rat ovariectomy-induced model of osteoporosis.

METHODS

The OVX osteoporosis model was established in female Sprague-Dawley rats by full bilateral ovariectomy. The rats were randomly divided into four groups, with the two experimental groups receiving an intraperitoneal injection of GYY4137 or sodium alendronate. The level of H2S in the plasma was determined and common laboratory indicators to diagnose osteoporosis, such as alkaline phosphatase (ALP) activity and the levels of osteocalcin (OCN), calcitonin, parathyroid hormone and leptin were measured. The bone mineral density (BMD) of the 4th and 5th lumbar vertebrae was measured using dual-energy X-ray absorptiometry. The maximum stress of femoral fracture was obtained through a three-point bending test of the femur.

RESULTS

The OVX osteoporosis model was successfully established. GYY4137 was injected to increase the level of H2S in the plasma in one group, designated OVX-GYY during the observation period (p < 0.05). At 12 weeks, the BMD value of the fourth lumbar vertebra in the OVX-GYY group had increased (p < 0.05). The BMD femur value in the OVX-vehicle group had decreased (p < 0.05). Bilateral ovariectomy leads to biochemical disorders related to bone metabolism and hormone levels in rat plasma (all p < 0.05). Ovariectomy also reduced blood calcium, blood phosphate and calcitonin, and increased parathyroid hormone and leptin. The opposite results were obtained for the groups with alendronate sodium or GYY4137 treatment (all p < 0.05).

CONCLUSIONS

Through the slow release of H2S, GYY4137 did an excellent job of simulating endogenous neuroendocrine gaseous signaling molecules. Exogenous H2S had a regulatory effect on osteoporosis in ovariectomized rats, showing potential value for the treatment of human postmenopausal osteoporosis.

Effect of lycopene on titanium implant osseointegration in ovariectomized rats

Background

Lycopene prevents bone loss in osteopenic models. However, the role of lycopene in the success rate of dental implants under osteopenic conditions remains unknown. The aim of this study was to evaluate whether lycopene prevents delayed implant osseointegration in an ovariectomized (OVX) rat model.

Methods

Thirty female Sprague-Dawley rats were randomly divided into the following groups: OVX with vehicle (OVX group), OVX with lycopene (OVX + lycopene group) and sham-operated with vehicle (sham group). Twelve weeks after ovariectomy or sham operation, titanium implants were placed into the distal metaphysis of the bilateral femurs of each rat. These rats were subsequently gavaged with lycopene (50 mg/kg/day) or vehicle. After 12 weeks of gavage, all rats were sacrificed, and specimens were harvested. Sample osseointegration was evaluated by biomechanical testing, 3D micro-computed tomography (micro-CT) analysis and histomorphometric analysis.

Results

Compared with the OVX group, the OVX + lycopene group showed a 69.3% increase in the maximum push-out force (p < 0.01). Micro-CT data for the femurs in the OVX + lycopene group showed significantly higher bone volume, trabecular thickness and less trabecular space than did those in the OVX group. The bone area (BA) around the implant and bone contact (BC) with the implant were increased by 72.3% (p < 0.01) and 51.4% (p < 0.01) in the OVX + lycopene group, respectively, compared with those in the OVX group. There was no significant difference in the mechanical test, micro-CT scanning and histomorphometric data between the OVX + lycopene and sham groups (p > 0.05).

Conclusions

Lycopene improved implant osseointegration, fixation and bone formation under osteopenic conditions, suggesting that lycopene is a promising therapeutic agent to prevent delayed implant osseointegration and bone loss under osteopenic conditions.

Pulsed electromagnetic fields (PEMF) attenuate changes in vertebral bone mass, architecture and strength in ovariectomized mice

Pulsed electromagnetic fields (PEMF) has been investigated as a noninvasive alternative method to prevent bone loss for postmenopausal osteoporosis (OP), and the bone tissue involved in these studies are usually long bones such as femur and tibia in OP patients or rat models. However, few studies have investigated the effects of PEMF on the vertebral bone in mice with OP. This study aimed to investigate whether PEMF preserve lumbar vertebral bone mass, microarchitecture and strength in ovariectomized (OVX) mouse model of OP and its associated mechanisms. Thirty 3-month-old female BALB/c mice were randomly divided into three groups (n=10): sham-operated control (Sham), ovariectomy (OVX), and ovariectomy with PEMF treatment (OVX+PEMF). The OVX+PEMF group was exposed to 15Hz, 1.6 mT PEMF for 8h/day, 7days/week. After 8weeks, the mice were sacrificed. The OVX+PEMF group showed lower body weight gain of mice induced by estrogen deficiency compared with OVX group. Biochemical analysis of serum demonstrated that serum bone formation markers including bone specific alkaline phosphatase (BALP), serum osteocalcin (OCN), osteoprotegerin (OPG) and N-terminal propeptide of type I procollagen (P1NP) were markedly higher in OVX+PEMF group compared with OVX group. Besides, serum bone resorption markers including tartrate-resistant acid phosphatase 5b (TRAP-5b) and C-terminal crosslinked telopeptides of type I collagen (CTX-I) were markedly lower in OVX+PEMF group compared with OVX group. Biomechanical test observed that OVX+PEMF group showed higher compressive maximum load and stiffness of the lumbar vertebrae compared with OVX group. Micro-computed tomography (μCT) and histological analysis of lumbar vertebrae revealed that PEMF partially prevented OVX-induced decrease of trabecular bone mass and deterioration of trabecular bone microarchitecture in lumbar vertebrae. Real-time PCR showed that the canonical Wnt signaling pathway of the lumbar vertebrae, including Wnt3a, LRP5 and β-catenin were markedly up-regulated in OVX+PEMF group compared with OVX group. Moreover, the mRNA expressions of RANKL and OPG were markedly up-regulated in OVX+PEMF group compared with OVX group, whereas no statistical difference in RANKL/OPG mRNA ratio was found between OVX+PEMF group and OVX group. Besides, our study also found that the RANK mRNA expression was down-regulated in OVX+PEMF group compared with OVX group. Taken together, we reported that long-term stimulation with PEMF treatment was able to alleviate lumbar vertebral OP in postmenopausal mice through a combination of increased bone formation and suppressed bone resorption related to regulating the skeletal gene expressions of Wnt3a/LRP5/β-catenin and OPG/RANKL/RANK signaling pathways.

Osteoprotective effects of salidroside in ovariectomized mice and diabetic mice

Salidroside, an active constituent from the root of Rhodiola rosea L., has multiple pharmacological effects, such as anti-cancer, anti-inflammatory and anti-oxidative properties, etc. However, its protective effect on bone tissue via regulating calcium homeostasis is yet to be determined. This study was performed to investigate if salidroside could protect against bone injuries induced by estrogen deficiency or hyperglycemia through modulating calcium homeostasis. Ovariectomized (OVX) mice and diabetic mice were treated with salidroside (20mg/kg) for 6 weeks. Safranin O staining and micro-CT were performed on the distal metaphysis of femur. The calcium content in serum, urine and femur was measured, and the mRNA and protein expressions of regulators in kidney were determined by PCR and immunoblotting, respectively. Treatment with salidroside increased bone calcium level and decreased urinary calcium excretion, consequently attenuating the deteriorations of trabecular bone in both OVX mice and diabetic mice. 25-Hydroxyvitamin D-24 hydroxylase expression was down-regulated and vitamin D receptor expression was up-regulated in kidney of both OVX mice and diabetic mice upon to salidroside treatment, which also inhibited the ovariectomy-induced decrease in expression of renal transcellular calcium transporters and the diabetes-induced enhancement in renal calcium-sensing receptor (CaSR) expression. Taken together, salidroside exerted osteoprotective effects by improving calcium homeostasis via regulating vitamin D metabolism and transcellular calcium transporters as well as modulating CaSR expression in kidney.

Estrogen protects both sexes against EAE by promoting common regulatory cell subtypes independent of endogenous estrogen

Autoimmune diseases including multiple sclerosis predominantly affect females. Although high levels of sex hormones, particularly estrogen (E2), can reduce proinflammatory immune responses, it remains unclear if a lack of endogenous sex hormones might affect treatment with exogenous sex hormones. Pretreatment with E2 almost completely prevents intact female and male mice from developing clinical and histological signs of experimental autoimmune encephalomyelitis (EAE) by promoting various regulatory immune cell phenotypes. To evaluate the effects of exogenous estrogen in the absence of endogenous sex hormones, the current study compared EAE severity and the emergence of different immunoregulatory cell populations after E2 pretreatment of ovariectomized (OVX) female versus male mice. We found that E2 equally protected both OVX females and males from EAE over a 21 day observation period concomitant with reduced total cell numbers in spleen and spinal cord (males only), but enhanced percentages of CD19⁺CD5⁺CD1d^hi, CD19⁺CD138⁺CD44^hi and CD19⁺Tim-1⁺ Breg cells, CD8⁺CD122⁺ Treg cells and CD11b⁺CD 206⁺ARG-1⁺ anti-inflammatory M2-like monocytes/macrophages in both groups. In contrast, E2 decreased the percentage of CD4⁺CD25⁺FoxP3⁺ Treg cells in OVX females but increased these Treg cells in males and intact female mice. These data suggest that with the exception of CD4⁺CD25⁺FoxP3⁺ Treg cells, E2 protection against EAE promotes highly overlapping immunoregulatory subsets in OVX females and males.

3-Piperidylethoxypterocarpan: A potential bone anabolic agent that improves bone quality and restores trabecular micro-architecture in ovariectomized osteopenic rats

A series of new 6H-benzofuro[3, 2-c]chromenes (BFC, pterocarpans) with structure-activity relationships were investigated for their potential use in osteoporosis treatment. One of the BFCs 3-piperidylethoxypterocarpan 20 promotes osteoblast differentiation and mineralization at a dose as low as 1 pM via activation of ER/P38MAPK/BMP-2 pathway. When evaluated for in-vivo osteogenic activity in female Sprague-Dawley rats, BFC 20 increased bone mineral density and new bone formation, compared with control at 1.0 and 10.0 mg/kg/body weight by oral gavage for 30 days. The compound was devoid of any uterotrophic effect and led to the new bone formation in adult ovariectomized osteopenic rats. BFC 20 compound also inhibited bone resorption by reducing Ovx induced increase in urinary CTx, thus exhibiting both bone anabolic and anti-catabolic action. Finally, BFC 20 treatment to Ovx rats led to improved trabecular microarchitectural restoration and exhibited therapeutic potential as a dual acting anti-osteoporotic agent for the management of osteoporosis.

L-Carnitine, but not coenzyme Q10, enhances the anti-osteoporotic effect of atorvastatin in ovariectomized rats

OBJECTIVE

Statins' therapy in osteoporosis can aggravate muscle damage. This study was designed to assess which agent, L-carnitine or coenzyme Q10, could enhance the anti-osteoporotic effect of atorvastatin while antagonizing myopathy in ovariectomized rats.

METHODS

Forty-eight female Sprague Dawley rats were used; forty rats were ovariectomized while eight were sham-operated. Eight weeks post-ovariectomy, rats were divided into ovariectomized-untreated group and four ovariectomized-treated groups (n=8) which received by gavage (mg/(kg∙d), for 8 weeks) 17β-estradiol (0.1), atorvastatin (50), atorvastatin (50)+L-carnitine (100), or atorvastatin (50)+coenzyme Q10 (20). At the end of therapy, bone mineral density (BMD), bone mineral content (BMC), and serum levels of bone metabolic markers (BMMs) and creatine kinase (CK) were measured. Femurs were used for studying the breaking strength and histopathological changes.

RESULTS

Treatment with atorvastatin+L-carnitine restored BMD, BMC, and bone strength to near normal levels. Estrogen therapy restored BMD and BMC to near normal levels, but failed to increase bone strength. Although atorvastatin and atorvastatin+coenzyme Q10 improved BMD, BMC, and bone strength, they failed to restore levels to normal. All treatments decreased BMMs and improved histopathological changes maximally with atorvastatin+L-carnitine which restored levels to near normal. Atorvastatin aggravated the ovariectomy-induced increase in CK level while estrogen, atorvastatin+L-carnitine, and atorvastatin+coenzyme Q10 decreased its level mainly with atorvastatin+L-carnitine which restored the level to near normal.

CONCLUSIONS

Co-administration of L-carnitine, but not coenzyme Q10, enhances the anti-osteoporotic effect of atorvastatin while antagonizing myopathy in ovariectomized rats. This could be valuable in treatment of osteoporotic patients. However, further confirmatory studies are needed.

Effects of yuja peel extract and its flavanones on osteopenia in ovariectomized rats and osteoblast differentiation

SCOPE

Yuja (Citrus junos Tanaka) possesses various health benefits, but its effects on bone health are unknown. In this study, the preventative effects of yuja peel ethanol extract (YPEE) on osteopenia were determined in ovariectomized (OVX) rats, and the mechanisms by which YPEE and its flavanones regulate osteoblastogenesis were examined in vitro.

METHODS AND RESULTS

The effects of YPEE on osteoblastogenesis were investigated in MC3T3-E1 cells. YPEE promoted alkaline phosphatase (ALP) activity, mineralization, and the expression of osteoblast differentiation marker genes, such as ALP, runt-related transcription factor 2 (Runx2), and osteocalcin. YPEE and its flavanones promoted osteoblast differentiation via BMP-2-mediated p38 and the Smad1/5/8 signaling pathway. YPEE supplementation significantly decreased body weight and increased uterine weight and bone mineral density in OVX rats. Based on a micro-CT analysis of femurs, YPEE significantly attenuated osteopenia and increased trabecular volume fraction, trabecular separation, and trabecular number (p < 0.05).

CONCLUSION

Dietary YPEE has a protective effect on OVX-induced osteopenia. YPEE and its flavanones promote osteoblastogenesis via the activation of the BMP/p38/Smad/Runx2 pathways. These results extend our knowledge of the beneficial effects of YPEE and provide a basis for the development of novel therapies for osteoporosis.

Renin inhibitor aliskiren exerts beneficial effect on trabecular bone by regulating skeletal renin-angiotensin system and kallikrein-kinin system in ovariectomized mice

SUMMARY

The skeletal renin-angiotensin system contributes to the development of osteoporosis. The renin inhibitor aliskiren exhibited beneficial effects on trabecular bone of osteoporotic mice, and this action might be mediated through angiotensin and bradykinin receptor pathways. This study implies the potential application of renin inhibitor in the management for postmenopausal osteoporosis.

INTRODUCTION

The skeletal renin-angiotensin system plays key role in the pathological process of osteoporosis. The present study is designed to elucidate the effect of renin inhibitor aliskiren on trabecular bone and its potential action mechanism in ovariectomized (OVX) mice.

METHODS

The OVX mice were treated with low dose (5 mg/kg) or high dose (25 mg/kg) of aliskiren or its vehicle for 8 weeks. The bone turnover markers were measured by ELISA. The structural parameters of trabecular bone at lumbar vertebra (LV) and distal femoral metaphysis were measured by micro-CT. The expression of messenger RNA (mRNA) and protein was studied by RT-PCR and immunoblotting, respectively.

RESULTS

Aliskiren treatment reduced urinary excretion of calcium and serum level of tartrate-resistant acid phosphatase in OVX mice. The treatment with aliskiren significantly increased bone volume (BV/TV) and connectivity density (Conn.D) of trabecular bone at LV-2 and LV-5 as well as dramatically enhanced BV/TV, Conn.D, bone mineral density (BMD/BV) and decreased bone surface (BS/BV) at the distal femoral end. Aliskiren significantly down-regulated the expression of angiotensinogen, angiotensin II (Ang II), Ang II type 1 receptor, bradykinin receptor (BR)-1, and osteocytic-specific gene sclerostin as well as the osteoclast-specific genes, including carbonic anhydrase II, matrix metalloproteinase-9, and cathepsin K.

CONCLUSIONS

This study revealed that renin inhibitor aliskiren exhibited the beneficial effects on trabecular bone of ovariectomy-induced osteoporotic mice, and the underlying mechanism for this action might be mediated through Ang II and BR signaling pathways in bone.

Effects of Korean red ginseng (Panax ginseng) on obesity and adipose inflammation in ovariectomized mice

ETHNOPHARMACOLOGICAL RELEVANCE

Korean red ginseng (ginseng, Panax ginseng C.A. Meyer) is a famous traditional drug used in Korea for the treatment and prevention of obesity, type 2 diabetes, cancer, and liver and cardiovascular diseases. Menopause is strongly associated with many of the aforementioned metabolic diseases and increased visceral obesity. The aims of this study were to investigate whether ginseng inhibits obesity and related disorders in ovariectomized (OVX) C57BL/6J mice, which is a mouse model of postmenopausal women, and to determine the mechanism of action involved in this process.

MATERIALS AND METHODS

After OVX mice were treated with 5% (w/w) ginseng for 15 weeks, we determined the effects of ginseng on obesity and adipose inflammation, angiogenesis, metalloproteinase (MMP) activity and metabolic parameters.

RESULTS

OVX mice had higher body weight, adipose tissue mass and adipocyte size when fed a high fat diet (HFD) compared with HFD-fed sham-operated mice. All of these parameters were significantly reduced in OVX mice fed a HFD supplemented with ginseng. Ginseng treatment also decreased blood vessel density, MMP activity, and mRNA levels of angiogenic factors (e.g., VEGF-A and FGF-2) and MMPs (e.g., MMP-2 and MMP-9) in adipose tissues of OVX mice. Infiltrating inflammatory cells and expression of inflammatory cytokines (e.g., CD68, TNFα and MCP-1) in adipose tissue were reduced by ginseng. Ginseng not only reduced the circulating levels of free fatty acids and triglycerides, but also normalized hyperinsulinemia and hyperglycemia in OVX mice. Hepatic lipid droplets were almost completely abolished by ginseng.

CONCLUSIONS

These results suggest that ginseng inhibited ovariectomy-induced obesity, adiposity, and adipocyte hypertrophy by modulating angiogenesis and MMP activity. Ginseng also suppressed adipose inflammation, insulin resistance, and hepatic steatosis in OVX mice. Thus, it is likely that ginseng may be a promising drug for the prevention and treatment of obesity and related disorders in obese postmenopausal women.

Resveratrol supplementation affects bone acquisition and osteoporosis: Pre-clinical evidence toward translational diet therapy

Osteoporosis is a major public health issue that is expected to rise as the global population ages. Resveratrol (RES) is a plant polyphenol with various anti-aging properties. RES treatment of bone cells results in protective effects, but dose translation from in vitro studies to clinically relevant doses is limited since bioavailability is not taken into account. The aims of this review is to evaluate in vivo evidence for a role of RES supplementation in promoting bone health to reduced osteoporosis risk and potential mechanisms of action. Due to multiple actions on both osteoblasts and osteoclasts, RES has potential to attenuate bone loss resulting from different etiologies and pathologies. Several animal models have investigated the bone protective effects of RES supplementation. Ovariectomized rodent models of rapid bone loss due to estrogen-deficiency reported that RES supplementation improved bone mass and trabecular bone without stimulating other estrogen-sensitive tissues. RES supplementation prior to age-related bone loss was beneficial. The hindlimb unloaded rat model used to investigate bone loss due to mechanical unloading showed RES supplementation attenuated bone loss in old rats, but had inconsistent bone effects in mature rats. In growing rodents, RES increased longitudinal bone growth, but had no other effects on bone. In the absence of human clinical trials, evidence for a role of RES on bone heath relies on evidence generated by animal studies. A better understanding of efficacy, safety, and molecular mechanisms of RES on bone will contribute to the determination of dietary recommendations and therapies to reduce osteoporosis. This article is part of a Special Issue entitled: Resveratol: Challenges in translating pre-clinical findings to improved patient outcomes.

Allopregnanolone's attenuation of the lordosis-inhibiting effects of restraint is blocked by the antiprogestin, CDB-4124

A brief restraint experience reduces lordosis behavior in ovariectomized females that have been hormonally primed with estradiol benzoate. The addition of progesterone to the priming prevents the lordosis inhibition. Based on prior studies with an inhibitor of progesterone metabolism, we have implicated the intracellular progesterone receptor, rather than progesterone metabolites, as responsible for this protection. However, the progesterone metabolite, allopregnanolone (3α-hydroxy-5α-pregnan-20-one), also prevents lordosis inhibition after restraint. In a prior study, we reported that the progestin receptor antagonist, RU486 (11β-(4-dimethylamino)phenyl-17β-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one), attenuated the effect of allopregnanolone. Because RU486 can also block the glucocorticoid receptor, in the current studies, we evaluated the effect of the progestin receptor antagonist, CDB-4124 (17α-acetoxy-21-methoxy-11β-[4-N,N-dimethyaminopheny]-19-norpregna-4,9-dione-3,20-dione), which is relatively devoid of antiglucocorticoid activity. Ovariectomized, Fischer rats were injected with 10 μg estradiol benzoate. Two days later, rats received either 60 mg/kg CDB-4124 or 20% DMSO/propylene glycol vehicle 1 h before injection with 4 mg/kg allopregnanolone. After a pretest to confirm sexual receptivity, rats were restrained for 5min and immediately tested for sexual behavior. Lordosis behavior was reduced by the restraint and attenuated by allopregnanolone. Pretreatment with CDB-4124 reduced allopregnanolone's effect. These findings support prior suggestions that allopreganolone reduces the response to restraint by mechanisms that require activation of the intracellular progesterone receptor.

Estrogen receptors mediate estradiol's effect on sensitization and CPP to cocaine in female rats: role of contextual cues

Preclinical studies show that estradiol enhances sensitization to cocaine in females by mechanisms not fully understood. These studies consistently show that ovariectomized (OVX) rats exhibit little or no sensitization to cocaine compared to OVX rats administered estradiol. In this study we varied the dose of cocaine (10, 15, and 30mg/kg), the length of cocaine treatment (from 5 to 10days) and the context of cocaine injections to determine if these factors play a role on estradiol's effects on cocaine sensitization. Because OVX rats are hormonally compromised, they are not representative of the natural state of the animal, and thus the physiological context of these studies remains unclear. To address this issue, we blocked ERs in gonadally intact females by icv administration of the antiestrogen ICI-182,780. Varying the dose or length of exposure to cocaine does not alter estradiol's effect on cocaine sensitization. In contrast, a highly context-dependent sensitization protocol results in robust sensitization even in OVX rats. Interestingly, using this protocol, sensitization in OVX rats diminished with time, suggesting that estradiol is necessary for the maintenance of cocaine sensitization. Blocking brain ERs with ICI completely abolishes the development and expression of cocaine sensitization in gonadally intact female rats, even when tested in a highly context-dependent sensitization protocol. Given these findings, we propose that activation of brain ERs is required for the development and maintenance of sensitization and CPP.

Comparison of female Fischer and Sprague-Dawley rats in the response to ketanserin

The effects of the 5-HT2A/2C receptor antagonist, ketanserin, on lordosis behavior were examined in hormonally primed, ovariectomized Fischer and Sprague-Dawley females. Rats were primed with 0.067μg/g body weight estradiol benzoate and 3.33μg/g body weight progesterone. After a pretest for sexual behavior, rats were injected with 0.416 to 10mg/kg ketanserin. In both strains, lordosis behavior, lordosis quality, and proceptivity were significantly reduced by ketanserin. There was modest evidence of a strain difference with Sprague-Dawley females slightly more sensitive to ketanserin. In a second experiment, the effects of 10mg/kg fluoxetine, 1mg/kg ketanserin, and their combination were examined to determine if the two drugs would have additive effects on sexual behavior. There was no evidence that the drugs were additive in their effect and the strains did not differ in their response to the combined treatment. These findings are discussed in relation to prior evidence for strain differences in the sexual behavioral response to fluoxetine and to a receptor agonist acting preferentially at 5-HT1A receptors.