RESUMEN

Age-related osteoporosis is a metabolic skeletal disorder caused by estrogen deficiency in postmenopausal women. Prolonged use of anti-osteoporotic drugs such as bisphosphonates and FDA-approved anti-resorptive selective estrogen receptor modulators (SERMs) has been associated with various clinical drawbacks. We recently discovered a low-molecular-weight biocompatible and osteoanabolic phytoprotein, called HKUOT-S2 protein (32 kDa), from Dioscorea opposita Thunb that can accelerate bone defect healing. Here, we demonstrated that the HKUOT-S2 protein treatment can enhance osteoblasts-induced ossification and suppress osteoporosis development by upregulating skeletal estrogen receptors (ERs) ERα, ERß, and GPR30 expressions in vivo. Also, HKUOT-S2 protein estrogenic activities promoted hMSCs-osteoblasts differentiation and functions by increasing osteogenic markers, ALP, and RUNX2 expressions, ALP activity, and osteoblast biomineralization in vitro. Fulvestrant treatment impaired the HKUOT-S2 protein-induced ERs expressions, osteoblasts differentiation, and functions. Finally, we demonstrated that the HKUOT-S2 protein could bind to ERs to exert osteogenic and osteoanabolic properties. Our results showed that the biocompatible HKUOT-S2 protein can exert estrogenic and osteoanabolic properties by positively modulating skeletal estrogen receptor signaling to promote ossification and suppress osteoporosis. Currently, there is no or limited data if any, on osteoanabolic SERMs. The HKUOT-S2 protein can be applied as a new osteoanabolic SERM for osteoporosis treatment.

RESUMEN

Fluctuations in estradiol levels at each stage of life in women are considered one of the causes of mental diseases through their effects on the central nervous system. During menopause, a decrease in estradiol levels has been reported to affect the serotonin nervous system and induce depression-like and anxiety symptoms. However, the regulation of brain and behaviour during childhood and adolescence is poorly understood. Moreover, the role of oestrogen receptors α and ß in the regulation of the serotonergic nervous system has been reported, but little is known about the involvement of G protein-coupled receptor 30. Therefore, in this study, we used an ovariectomized childhood mouse model to analyse behaviour and investigate the effects on the serotonin nervous system. We showed that ovariectomy surgery at 4 weeks of age, which is the weaning period, induced a decrease in spontaneous locomotor activity during the active period and a preference for novel mice over familiar mice in the three-chamber social test at 10 weeks of age. In addition, the administration of G-1, a protein-coupled receptor 30 agonist, to ovariectomized mice suppressed spontaneous locomotor activity and the preference for novel mice. Furthermore, we demonstrated that childhood ovariectomy induces increased tryptophan hydroxylase gene expression in the raphe nucleus and increased serotonin release in the amygdaloid nucleus, and administration of G-1 ameliorated these effects. Our study suggests that G protein-coupled receptor 30-mediated regulation of serotonin synthesis is involved in changes in activity and social-cognitive behaviour due to decreased estradiol levels during childhood.

RESUMEN

AIM: Given estrogen's recognized regulatory influence on diverse metabolic and immune functions, this study sought to explore its potential impact on fibrosis and elucidate the underlying metabolic regulations. METHODS: Female mice underwent ovary removal surgery, followed by carbon tetrachloride (CCl4) administration to induce liver injury. Biochemical index analysis and histopathological examination were then conducted. The expression levels of alpha-smooth muscle actin (α-SMA), transforming growth factor-ß (TGF-ß), and collagen type 1 alpha 1 chain (COL1A1) were assessed using western blotting to further elucidate the extent of liver injury. Finally, metabolite extraction and metabolomic analysis were performed to evaluate metabolic changes. RESULTS: Ovary removal exacerbated CCl4-induced liver damage, while estrogen supplementation provided protection against hepatic changes resulting from OVX. Furthermore, estrogen mitigated liver injury induced by CCl4 treatment in vivo. Estrogen supplementation significantly restored liver damage induced by OVX and CCl4. Comparative analysis revealed significant alterations in pathways including aminoacyl-tRNA biosynthesis, glycine, serine, and threonine metabolism, lysine degradation, and taurine and hypotaurine metabolism in estrogen treatment. CONCLUSION: Estrogen supplementation alleviates liver injury induced by OVX and CCl4, highlighting its protective effects against fibrosis and associated metabolic alterations.

Asunto(s)

RESUMEN

Recent interest in preventing the development of osteoporosis has focused on the regulation of redox homeostasis. However, the action of lycopene (LYC), a strong natural antioxidant compound, on osteoporotic bone loss remains largely unknown. Here, we show that oral administration of LYC to OVX rats for 12 weeks reduced body weight gain, improved lipid metabolism, and preserved bone quality. In addition, LYC treatment inhibited ROS overgeneration in serum and bone marrow in OVX rats, and in BMSCs upon H2O2 stimulation, leading to inhibiting adipogenesis and promoting osteogenesis during bone remodeling. At the molecular level, LYC improved bone quality via an increase in the expressions of FoxO1 and Runx2 and a decrease in the expressions of PPARγ and C/EBPα in OVX rats and BMSCs. Collectively, these findings suggest that LYC attenuates osteoporotic bone loss through promoting osteogenesis and inhibiting adipogenesis via regulation of the FoxO1/PPARγ pathway driven by oxidative stress, presenting a novel strategy for osteoporosis management.

Asunto(s)

RESUMEN

Hydrolyzed egg yolk peptide (YPEP) was shown to increase bone mineral density in ovariectomized rats. However, the underlying mechanism of YPEP on osteoporosis has not been explored. Recent studies have shown that Wnt/ß-catenin signaling pathway and gut microbiota may be involved in the regulation of bone metabolism and the progression of osteoporosis. The present study aimed to explore the preventive effect of the YPEP supplementation on osteoporosis in ovariectomized (OVX) rats and to verify whether YPEP can improve osteoporosis by regulating Wnt/ß-catenin signaling pathway and gut microbiota. The experiment included five groups: sham surgery group (SHAM), ovariectomy group (OVX), 17-ß estradiol group (E2: 25 µg /kg/d 17ß-estradiol), OVX with low-dose YPEP group (LYPEP: 10 mg /kg/d YPEP) and OVX with high-dose YPEP group (HYPEP: 40 mg /kg/d YPEP). In this study, all the bone samples used were femurs. Micro-CT analysis revealed improvements in both bone mineral density (BMD) and microstructure by YPEP treatment. The three-point mechanical bending test indicated an enhancement in the biomechanical properties of the YPEP groups. The serum levels of bone alkaline phosphatase (BALP), bone gla protein (BGP), calcium (Ca), and phosphorus (P) were markedly higher in the YPEP groups than in the OVX group. The LYPEP group had markedly lower levels of alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and C-terminal telopeptide of type I collagen (CTX-I) than the OVX group. The YPEP groups had significantly higher protein levels of the Wnt3a, ß-catenin, LRP5, RUNX2 and OPG of the Wnt/ß-catenin signaling pathway compared with the OVX group. Compared to the OVX group, the ratio of OPG/RANKL was markedly higher in the LYPEP group. At the genus level, there was a significantly increase in relative abundance of Lachnospiraceae_NK4A136_group and a decrease in Escherichia_Shigella in YPEP groups, compared with the OVX group. However, in the correlation analysis, there was no correlation between these two bacteria and bone metabolism and microstructure indexes. These findings demonstrate that YPEP has the potential to improve osteoporosis, and the mechanism may be associated with its modulating effect on Wnt/ß-catenin signaling pathway.

Asunto(s)

RESUMEN

Hyperalgesia is typified by reduced pain thresholds and heightened responses to painful stimuli, with a notable prevalence in menopausal women, but the underlying mechanisms are far from understood. ß-Aminoisobutyric acid (BAIBA), a product of valine and thymine catabolism, has been reported to be a novel ligand of the Mas-related G protein coupled receptor D (MrgprD), which mediates pain and hyperalgesia. Here, we established a hyperalgesia model in 8-week-old female mice through ovariectomy (OVX). A significant increase in BAIBA plasma level was observed and was associated with decline of mechanical withdrawal threshold, thermal and cold withdrawal latency in mice after 6 weeks of OVX surgery. Increased expression of MrgprD in dorsal root ganglion (DRG) was shown in OVX mice compared to Sham mice. Interestingly, chronic loading with BAIBA not only exacerbated hyperalgesia in OVX mice, but also induced hyperalgesia in gonadally intact female mice. BAIBA supplementation also upregulated the MrgprD expression in DRG of both OVX and intact female mice, and enhanced the excitability of DRG neurons in vitro. Knockout of MrgprD markedly suppressed the effects of BAIBA on hyperalgesia and excitability of DRG neurons. Collectively, our data suggest the involvement of BAIBA in the development of hyperalgesia via MrgprD-dependent pathway, and illuminate the mechanisms underlying hyperalgesia in menopausal women.

Asunto(s)

RESUMEN

Spinal fixation surgery has been increasingly performed in patients with osteoporosis. Romosozumab, a drug that was introduced in Japan recently, is known to possibly promote bone healing. However, few studies have reported the therapeutic effects of romosozumab in clinical practice in Japan. Therefore, here, we investigated the effects of romosozumab dosage on bone fusion promotion using an ovariectomized rat spinal fusion model. Eight-week-old female Sprague-Dawley rats were matched by body weight and divided into three groups: 1.0 romosozumab (R) group (Evenity®, 25 mg/kg), 1/10R group (Evenity®, 2.5 mg/kg), and control (C) group (saline). Subcutaneous injections were administered twice a week for 8 weeks postoperatively. Computed tomography scans were performed every 2 weeks from the time of surgery till 8 weeks postoperatively. The mean fusion rates in terms of volume were significantly higher in the R groups [1/10R, 1.0R] than in the C group from 4 weeks postoperatively. The rate of increase was significantly higher in the 1.0R group from 4 weeks postoperatively and in the 1/10R group from 6 weeks postoperatively, than in the C group. The proportion of trabecular bone area was approximately 1.5 times higher in the R groups than in the C group. No significant differences were observed between the R groups. Our results suggest that romosozumab stimulates bone growth at the graft site, and similar effects were achieved at 1/10 of the standard dosage.

Asunto(s)

RESUMEN

BACKGROUND: Postmenopausal osteoporosis (PMOP) is a prevalent disease, which features decreased bone mass, bone weakness and deteriorated bone microstructure in postmenopausal women. Although many factors have been revealed to contribute to the occurrence of PMOP, its mechanism remains undefined. This work aimed to identify significant changes in gene expression during PMOP formation and to examine the most valuable differential genes in postmenopausal osteoporosis versus the control group. METHODS: The GSE68303 dataset that contains 12 ovariectomize (OVX) experimental and 11 sham groups was downloaded and analyzed. The results indicated that interferon regulatory factor 4 (IRF4) might be a hub gene in the development of postmenopausal osteoporosis. Western blot and immunohistochemistry were carried out to evaluate IRF4 levels in thoracic vertebra extracts from OVX and Sham mice. To assess IRF4's impact on osteogenic differentiation in postmenopausal bone marrow mesenchymal stem cells (BM-MSCs), IRF4 overexpression (OV-IRF4) and knockdown (Sh-IRF4) plasmids were constructed. RESULTS: The results showed that comparing with the sham group, bone samples from the OVX group showed higher IRF4 expression. Alkaline phosphatase (ALP) staining revealed that IRF4 overexpression significantly inhibited ALP activity, while IRF4 knockdown promoted ALP activity in BM-MSCs. Simvastatin-treated OVX mice showed increased total bone volume/total tissue volume (BV/TV) and elevated Runx2 expression by immunohistochemical staining compared with the OVX group. CONCLUSIONS: This study demonstrated that IRF4 is associated with OVX induced osteoporosis, it can regulate bone stability by inhibiting the osteogenic differentiation BM-MSCs. This study may help enhance our understanding of the molecular mechanism of PMOP formation, providing new insights into estrogen defiance induced osteoporosis.

Asunto(s)

RESUMEN

Sparassis crispa, an edible mushroom, has been reported to show many kinds of physiological functions. The present paper focused on reducing body weight, subcutaneous fat, and visceral fat gain in ovariectomized (OVX) mice. Using the fruiting body powder of the indoor cultivation S. crispa (IT S. crispa: ITSc), one week after the OVX, ITSc was administered to two OVX groups by per os (p.o). In the sham group, 10 mL/kg water and 10 mL/kg saline were administered by p.o. and subcutaneous adm, respectively. OVX groups were divided into four groups. These treatments were performed on animals 6 days a week for 8 weeks. Subcutaneous and visceral fat measurements were performed under inhalation anesthesia with isoflurane using a Latheta LCT-200 X-ray CT system. The biochemical markers and the mRNA expression levels of the PPARγ, adiponectin, TNF-α, PPARα, and leptin were measured. Significant increases in body weight, fat ratio, and glucose levels were detected in OVX mice compared to sham mice. These increases were significantly blocked by ITSc, but not estradiol. Furthermore, ITSc treatment significantly increased adiponectin and leptin levels in adipose tissue. These results suggest that ITSc improves lipid abnormalities due to the less activity of women's ovary function, excluding estrogen functions.

RESUMEN

This study investigated the effects of quercetin on the alterations of serum elements in perimenopausal depression rat model induced by ovariectomy combined with chronic unpredictable mild stress (OVX-CUMS) and possible mechanisms. According to the results of the sucrose preference test, the rats were randomly assigned to four groups: sham, OVX-CUMS, OVX-CUMS + 17ß-estradiol (17ß-estradiol: 0.27 mg/kg.bw), and OVX-CUMS + Quercetin (Quercetin: 50 mg/kg.bw). At the end of experiment, serum and prefrontal cortex of rats were collected. The inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that levels of calcium (Ca), magnesium (Mg), selenium (Se), cobalt (Co) and zinc (Zn) decreased, and levels of iron (Fe) and copper (Cu) increased in serum and prefrontal cortex of OVX-CUMS rats compared with sham group (p < 0.01). Meanwhile, the levels of the above elements in prefrontal cortex had correlation with behavioral characteristics in OVX-CUMS rats (p < 0.05 or p < 0.01). The abnormal elements in serum may cross blood-brain-barrier into the brain and induce oxidative stress, leading to ferroptosis. Furtherly, the expressions of ferroptosis-related protein including GPX4 and SLC7A11 were decreased in prefrontal cortex of OVX-CUMS rats (p < 0.01), which confirmed the above results. Quercetin treatment restored the above abnormal indicators (p < 0.05 or p < 0.01) induced by OVX-CUMS in rats. Our study suggested that quercetin regulated variation of elements in serum and prefrontal cortex, further inhibiting ferroptosis in prefrontal cortex through alleviating oxidative stress in OVX-CUMS rats.

RESUMEN

Osteoporosis is a systemic osteopathy characterized by bone metabolism disorders that become more serious with age increases in postmenopausal women. Recent studies have found that antler protein is the main bioactive component of cervus pantotrichum, and it has a positive regulatory effect on bone metabolism and can improve estrogen level. This study aimed to investigate the effect of velvet antler extract (VAE) on the prevention of osteoporosis and the modulation of gut microbiota in ovariectomized (OVX) mice. OVX mice treated with 12 weeks of VAE exhibited higher levels of serum BGP, Ca2+, CT, and HyP (p < .05). Micro-CT scans showed that VAE significantly elevated bone volume fraction (BV/TV), trabecular bone number (Tb.N), trabecular bone thickness (Tb.Th), trabecular bone connection density (Conn.D), decreased trabecular separation (Tb.Sp), and structural modality index (SMI) than untreated OVX mice. The right tibial retinaculum in the VAE group was clearer, with a clearer reticular structure, smaller gaps, a tighter distribution, and a more orderly arrangement. The gut microbiota of the cecal contents was analyzed by 16 s rDNA amplicon sequencing. The data indicated that VAE modulated the species, numbers, and diversity of the gut microbiota in OVX mice. Ovariectomy caused dysbiosis of the intestinal microbiota by increasing the ratio of Firmicutes to Bacteroidetes in mice, but the ratio decreased after treatment with VAE. These results suggest that VAE has a therapeutic effect on OVX mice via modulate bone-related biochemical markers in serum and structure of gut microbiota.

RESUMEN

The mutation and overexpression of the alpha-synuclein protein (αSyn), described as synucleinopathy, is associated with Parkinson's disease (PD)-like pathologies. A higher prevalence of PD is documented for men versus women, suggesting female hormones' implication in slowing PD progression. The nigrostriatal dopamine (DA) neurons in rodent males are more vulnerable to toxins than those in females. The effect of biological sex on synucleinopathy remains poorly described and was investigated using mice knocked out for murine αSyn (SNCA-/-) and also overexpressing human αSyn (SNCA-OVX) compared to wildtype (WT) mice. All the mice showed decreased locomotor activity with age, and more abruptly in the male than in the female SNCA-OVX mice; anxiety-like behavior increased with age. The SNCA-OVX mice had an age-dependent accumulation of αSyn. Older age was associated with the loss of nigral DA neurons and decreased striatal DA contents. The astrogliosis, microgliosis, and cytokine concentrations increased with aging. More abrupt nigrostriatal DA decreases and increased microgliosis were observed in the male SNCA-OVX mice. Human αSyn overexpression and murine αSyn knockout resulted in behavioral dysfunctions, while only human αSyn overexpression was toxic to DA neurons. At 18 months, neuroprotection was lost in the female SNCA-OVX mice, with a likely loss of estrus cycles. In conclusion, sex-dependent αSyn toxicity was observed, affecting the male mice more significantly.

Asunto(s)

RESUMEN

Irisin is a peptide secreted by skeletal muscle that plays a major role in bone metabolism. Experiments in mouse models have shown that administration of recombinant irisin prevents disuse-induced bone loss. In this study, we aimed to evaluate the effects of irisin treatment for the prevention of bone loss in the ovariectomized (Ovx) mouse, the animal model commonly used to investigate osteoporosis caused by estrogen deficiency. Micro-Ct analysis conducted on Sham mice (Sham-veh) and Ovx mice treated with vehicle (Ovx-veh) or recombinant irisin (Ovx-irisn) showed bone volume fraction (BV/TV) decreases in femurs (Ovx-veh 1.39± 0.71 vs. Sham-veh 2.84 ± 1.23; p = 0.02) and tibia at both proximal condyles (Ovx-veh 1.97 ± 0.68 vs. Sham-veh 3.48 ± 1.26; p = 0.03) and the subchondral plate (Ovx-veh 6.33 ± 0.36 vs. Sham-veh 8.18 ± 0.41; p = 0.01), which were prevented by treatment with a weekly dose of irisin for 4 weeks. Moreover, histological analysis of trabecular bone showed that irisin increased the number of active osteoblasts per bone perimeter (Ovx-irisin 32.3 ± 3.9 vs. Ovx-veh 23.5 ± 3.6; p = 0.01), while decreasing osteoclasts (Ovx-irisin 7.6 ± 2.4 vs. Ovx-veh 12.9 ± 3.04; p = 0.05). The possible mechanism by which irisin enhances osteoblast activity in Ovx mice is upregulation of the transcription factor Atf4, one of the key markers of osteoblast differentiation, and osteoprotegerin, thereby inhibiting osteoclast formation.

Asunto(s)

RESUMEN

Imbalance of bone homeostasis induces bone degenerative diseases such as osteoporosis. Hedgehog (Hh) signaling plays critical roles in regulating the development of limb and joint. However, its unique role in bone homeostasis remained largely unknown. Here, we found that canonical Hh signaling pathway was gradually augmented during osteoclast differentiation. Genetic inactivation of Hh signaling in osteoclasts, using Ctsk-Cre;Smof/f conditional knockout mice, disrupted both osteoclast formation and subsequent osteoclast-osteoblast coupling. Concordantly, either Hh signaling inhibitors or Smo/Gli2 knockdown stunted in vitro osteoclast formation. Mechanistically, Hh signaling positively regulated osteoclast differentiation via transactivation of Traf6 and stabilization of TRAF6 protein. Then, we identified connective tissue growth factor (CTGF) as an Hh-regulatory bone formation-stimulating factor derived from osteoclasts, whose loss played a causative role in osteopenia seen in CKO mice. In line with this, recombinant CTGF exerted mitigating effects against ovariectomy induced bone loss, supporting a potential extension of local rCTGF treatment to osteoporotic diseases. Collectively, our findings firstly demonstrate that Hh signaling, which dictates osteoclast differentiation and osteoclast-osteoblast coupling by regulating TRAF6 and CTGF, is crucial for maintaining bone homeostasis, shedding mechanistic and therapeutic insights into the realm of osteoporosis.

Asunto(s)

RESUMEN

BACKGROUND: To explore the effect and mechanism of action of miR-210 on postmenopausal osteoporosis (PMPO) in ovariectomized rats in vivo. METHODS: An ovariectomized (OVX) rat model was established by ovariectomy. Tail vein injection was performed to overexpress and knock down miR-210 in OVX rats, followed by the collection of blood and femoral tissues from each group of rats. And quantitative real-time polymerase chain reaction (qRT-PCR) was applied to assess the expression level of miR-210 in femoral tissues of each group. Micro computed tomography (Micro CT) was adopted to scan the microstructure of the femoral trabecula in each group to obtain relevant data like bone mineral density (BMD), bone mineral content (BMC), trabecular bone volume fraction (BV/TV), trabecular thickness (Tb.Th), bone surface-to-volume ratio (BS/BV), and trabecular separation (Tb.Sp). ELISA was used for determining the level of bone alkaline phosphatase (BALP), amino-terminal propeptide of type I procollagen (PINP), osteocalcin (OCN), and C-terminal telopeptide of type I collagen (CTX-1) in serum; and Western blot for the protein level of Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and collagen type I alpha 1 (COL1A1) in femoral tissues. RESULTS: MiR-210 expression was significantly decreased in femoral tissues of OVX rats. Overexpression of miR-210 could obviously increase BMD, BMC, BV/TV and Tb.Th, whereas significantly decrease BS/BV and Tb.Sp in femurs of OVX rats. Moreover, miR-210 also downregulated BALP and CTX-1 level, upregulated PINP and OCN level in the serum of OVX rats promoted the expression of osteogenesis-related markers (Runx2, OPN and COL1A1) in the femur of OVX rats. Additionally, further pathway analysis revealed that high expression of miR-210 activated the vascular endothelial growth factor (VEGF)/Notch1 signaling pathway in the femur of OVX rats. CONCLUSION: High expression of miR-210 may improve the micromorphology of bone tissue and modulate bone formation and resorption in OVX rats by activating the VEGF/Notch1 signaling pathway, thereby alleviating osteoporosis. Consequently, miR-210 can serve as a biomarker for the diagnosis and treatment of osteoporosis in postmenopausal rats.

Asunto(s)

RESUMEN

Introduction: Histomorphometry of rodent metaphyseal trabecular bone, by histology or microCT, is generally restricted to the mature secondary spongiosa, excluding the primary spongiosa nearest the growth plate by imposing an 'offset'. This analyses the bulk static properties of a defined segment of secondary spongiosa, usually regardless of proximity to the growth plate. Here we assess the value of trabecular morphometry that is spatially resolved according to the distance 'downstream' of-and thus time since formation at-the growth plate. Pursuant to this, we also investigate the validity of including mixed primary-secondary spongiosal trabecular bone, extending the analysed volume 'upstream' by reducing the offset. Both the addition of spatiotemporal resolution and the extension of the analysed volume have potential to enhance the sensitivity of detection of trabecular changes and to resolve changes occurring at different times and locations. Method: Two experimental mouse studies of trabecular bone are used as examples of different factors influencing metaphyseal trabecular bone: (1) ovariectomy (OVX) and pharmacological prevention of osteopenia and (2) limb disuse induced by sciatic neurectomy (SN). In a third study into offset rescaling, we also examine the relationship between age, tibia length, and primary spongiosal thickness. Results: Bone changes induced by either OVX or SN that were early or weak and marginal were more pronounced in the mixed primary-secondary upstream spongiosal region than in the downstream secondary spongiosa. A spatially resolved evaluation of the entire trabecular region found that significant differences between experimental and control bones remained undiminished either right up to or to within 100 µm from the growth plate. Intriguingly, our data revealed a remarkably linear downstream profile for fractal dimension in trabecular bone, arguing for an underlying homogeneity of the (re)modelling process throughout the entire metaphysis and against strict anatomical categorization into primary and secondary spongiosal regions. Finally, we find that a correlation between tibia length and primary spongiosal depth is well conserved except in very early and late life. Conclusions: These data indicate that the spatially resolved analysis of metaphyseal trabecular bone at different distances from the growth plate and/or times since formation adds a valuable dimension to histomorphometric analysis. They also question any rationale for rejecting primary spongiosal bone, in principle, from metaphyseal trabecular morphometry.

Asunto(s)

RESUMEN

BACKGROUND: With increasing knowledge about the gut - bone axis, more studies for treatments based on the regulation of postmenopausal osteoporosis by gut microbes are being conducted. Based on our previous work, this study was conducted to further investigate the therapeutic effects of Lactobacillus rhamnosus GG (LGG) on ovariectomized (OVX) model rats and the immunological and microecological mechanisms involved. RESULTS: We found a protective effect of LGG treatment in OVX rats through changes in bone microarchitecture, bone biomechanics, and CTX-I, PINP, Ca, and RANKL expression levels. LGG was more advantageous in promoting osteogenesis, which may be responsible for the alleviation of osteoporosis. Th17 cells were imbalanced with Treg cells in mediastinal lymph nodes and bone marrow, with RORγt and FOXP3 expression following a similar trend. TNF-α and IL-17 expression in colon and bone marrow increased, while TGF-ß and IL-10 expression decreased; however, LGG treatment modulated these changes and improved the Th17/Treg balance significantly. Regarding the intestinal barrier, we found that LGG treatment ameliorated estrogen deficiency-induced inflammation and mucosal damage and increased the expression of GLP-2 R and tight junction proteins. Importantly, 16S rRNA sequencing showed a significant increase in the Firmicutes/Bacteroidetes ratio during estrogen deficiency. Dominant intestinal flora showed significant differences in composition; LGG treatment regulated the various genera that were imbalanced in OVX, along with modifying those that did not change significantly in other groups with respect to the intestinal barrier, inflammation development, and bile acid metabolism. CONCLUSIONS: Overall, LGG ameliorated estrogen deficiency-induced osteoporosis by regulating the gut microbiome and intestinal barrier and stimulating Th17/Treg balance in gut and bone.

Asunto(s)

RESUMEN

BACKGROUND: Fractures caused by osteoporosis (OP) are one of the main causes of death in the elderly, bringing a heavy burden to the country and society. The imbalance between osteoblast-mediated osteogenesis and osteoclast-mediated bone resorption is an important cause of OP. Therefore, finding drugs that can regulate this dynamic balance can be an important way to treat osteoporosis. Surfactin is a highly effective biosurfactant derived from Bacillus subtilis and it has been proven to have various pharmacological effects in previous studies, but its effect on bone metabolism remains unknown. Here, we performed a study on the role and mechanism of Surfactin in inhibiting osteoclastogenesis and its possible mechanism as well as the role in promoting osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). METHODS: We investigated the effect of Surfactin on osteoclast differentiation and osteogenic differentiation in vitro and in vivo. The effect of Surfactin on the activity of osteoclastogenesis and osteogenesis was verified by CCK-8 assay, quantitative Real-time polymerase chain reaction (qPCR) and Western blotting analysis were used to verify the effect of Surfactin on osteoclast and osteogenic differentiation-specific genes and proteins. The effect of Surfactin on TRAP、ALP activity and mineral deposition was verified by TRAP、ALP and ARS staining. We then used an ovariectomy-induced osteoporosis mice model to observe the effect of Surfactin in vivo. RESULTS: Surfactin is noncytotoxic to BMMs, RAW264.7, and BMSCs. And it can effectively inhibit osteoclastogenesis and promote osteogenic differentiation. Moreover, we found that Surfactin can inhibit the differentiation of osteoclasts through the NF-κB signaling pathway. Surfactin can also alleviate bone loss in ovariectomy-induced osteoporosis mice. CONCLUSIONS: Our results suggest that Surfactin can inhibit osteoclastogenesis through the NF-κB signaling pathway, promote the osteogenic differentiation of BMSCs, and also can effectively alleviate bone loss in ovariectomy-induced osteoporosis mice.

Asunto(s)

RESUMEN

The imbalance of bone homeostasis is the root cause of osteoporosis. However current therapeutic approaches mainly focus on either anabolic or catabolic pathways, which often fail to turn the imbalanced bone metabolism around. Herein we reported that a SIRT-1 agonist mediated molecular therapeutic strategy to reverse the imbalance in bone homeostasis by simultaneously regulating osteogenesis and osteoclastogenesis via locally sustained release of SRT2104 from mineral coated acellular matrix microparticles. Immobilization of SRT2104 on mineral coating (MAM/SRT) harnessing their electrostatic interactions resulted in sustained release of SIRT-1 agonist for over 30 days. MAM/SRT not only enhanced osteogenic differentiation and mineralization, but also attenuated the formation and function of excessive osteoclasts via integrating multiple vital upstream signals (ß-catenin, FoxOs, Runx2, NFATc1, etc.) in vitro. Osteoporosis animal model also validated that it accelerated osteoporotic bone healing and improved osseointegration of the surrounding bone. Overall, our work proposes a promising strategy to treat osteoporotic bone defects by reversing the imbalance in bone homeostasis using designated small molecule drug delivery systems.

RESUMEN

Objective: With the deepening of magnetic biomedical effects and electromagnetic technology, some medical instruments based on static magnetic field (SMF) have been used in orthopedic-related diseases treatment. Studies have shown SMF could combat osteoporosis by regulating the differentiation of mesenchymal stem cells (MSCs), osteoblast and osteoclast. With the development of nanotechnology, iron oxide nanoparticles (IONPs) have been reported to regulate the process of bone anabolism. As for SMF combined with IONPs, studies indicated osteogenic differentiation of MSCs were promoted by the combination of SMF and IONPs. However, there are few reports on the effects of SMF combined with IONPs on osteoclast. Herein, the purpose of this study was to investigate the effects of high static magnetic field (HiSMF) combined with IONPs on unloading-induced bone loss in vivo and osteoclastic formation in vitro, and elucidated the potential molecular mechanisms. Methods: In vivo, C57BL/6 â€‹J male mice were unloaded via tail suspension or housed normally. The hindlimb of mice were fixed and exposed to 1-2 â€‹T SMF for 1 â€‹h every day, 10 â€‹mg/kg of Ferumoxytol or saline were injected by tail vein once a week, last for 4 weeks. Bone microstructure, mechanical properties, and osteoclastogenesis were examined respectively. In vitro, the RAW264.7 â€‹cells were used to assess the effects of 1-2 â€‹T SMF combined with IONPs in osteoclastogenesis. The iron content was detected by atomic absorption spectrometry and Prussian blue staining. DCFH-DA and MitoSOX™ fluorescence staining were used to assess oxidative stress levels. NF-κB and MAPK signaling pathways were examined by western blot assay. Results: In vivo, the results showed 1-2 â€‹T SMF and IONPs prevented the damage to bone microstructure and improved the mechanical properties, diminished the number of osteoclasts in unloaded mice, 1-2 â€‹T SMF combined with IONPs was found more effective. The iron content in the liver and spleen was reduced by the combination of 1-2 â€‹T SMF and IONPs, enhancing iron levels in the femur. In vitro, osteoclast formation was inhibited by 1-2 â€‹T SMF and IONPs treatment, and 1-2 â€‹T SMF combined with IONPs had a more pronounced effect. Moreover, iron uptake of IONPs in osteoclast was reduced to 1-2 â€‹T SMF exposure. Oxidative stress levels were decreased in osteoclast differentiation under 1-2 â€‹T SMF combined with IONPs treatment. Molecularly, the expression of NF-κB and MAPK signaling pathways were inhibited under 1-2 â€‹T SMF combined with IONPs in osteoclastogenesis. Conclusions: Synthetically, our research illustrated 1-2 â€‹T SMF combined with IONPs prevented unloading-induced bone loss by regulating iron metabolism in osteoclastogenesis.Translational potential of this article: As a non-invasive alternative therapy, some medical instruments based on SMF have been used for orthopedic-related diseases treatment for their portability, cheapness and safety. Ferumoxytol (Feraheme™), the first FDA-approved IONP drug for the treatment of iron deficiency anemia, has been also adapted in translational research for osteoporosis. Based on the above-mentioned two points, we found the synergistic effects of SMF and Ferumoxytol for treatment of experimental osteoporosis. These results show translational potentials for clinical application.