Search Results (51)

Osteoporosis is a bone disease characterized by low bone mass and changes in bone architecture, often leading to fractures and thereby decreased functional status in affected patients. About 200 million people worldwide suffer from osteoporosis, with women being affected earlier in life and more often than men. Various factors, such as genetic background, comorbidities, alcohol abuse, and medications such as glucocorticoids, are known to contribute to the development of osteoporosis. Due to the changing demographics, osteoporosis is becoming increasingly prevalent, and with this, the rate of fractures is expected to increase in the coming years. To investigate therapeutic options for treatment and to elucidate disease-causing mechanisms, various in vivo and in vitro osteoporosis models have been developed. In vivo models, in particular small animal models, remain the gold standard for osteoporosis research and the most used model to illustrate osteoporosis is the ovariectomized mouse. While in vivo models largely reflect the systemic and biological conditions, the transferability of findings to human patients is low and ethical concerns for laboratory animals must be considered. Thanks to tremendous technological improvements, such as on-a-chip platforms and high-end bioreactor systems, sophisticated in vitro models are of growing interest. These models offer the possibility of using complex cell systems, human cells from single donors, and 3D models, thus bridging the transferability gap, providing a platform for the introduction of personalized precision medicine, and ultimately replacing animal testing. Here, we summarize and discuss recent in vivo, in vitro, and in silico osteoporosis research approaches. Full article

Background: Premenopausal women typically exhibit superior glucose metabolism compared to males, but this metabolic advantage is lost after menopause. The primary cause is the sharp decline in estrogen levels post-menopause. Genistein, a natural compound predominantly derived from leguminous plants, possesses structural similarity to estrogen. This enables specific binding to estrogen receptors, allowing genistein to exert estrogen-mimicking effects under conditions of estrogen deficiency. The aim of this study was to investigate the effects and potential mechanisms of genistein on glucose metabolism in the liver and skeletal muscle of ovariectomized (OVX) mice fed a high-fat diet (HFD). Methods: Animal experiments were performed using 8-week-old mice that were OVX to construct a model of estrogen deficiency and impaired their glucose metabolism by a continuous HFD. Genistein was administered by gavage (50 mg/kg-day) for 10 weeks and 17β-estradiol was administered subcutaneously (50 μg/kg) every 4 days for 10 weeks as a positive control. Results: Genistein significantly improved glucose metabolism (including fasting glucose, postprandial glucose, serum glucose levels, and HOMA-IR index) but did not affect serum estrogen levels and uterine weights in OVX mice. Genistein promoted increased expression and translocation of glucose transporter 4 (GLUT4) in the gastrocnemius muscle, enhanced phosphorylation of the PI3K/AKT pathway, and upregulated expression of the G protein-coupled estrogen receptor (GPER). Concurrently, it stimulates hepatic glycogen accumulation and upregulates GLUT2 expression in the liver. Conclusions: GEN improves glucose metabolism in ovariectomized mice, and this improvement is primarily attributed to increased expression and membrane translocation of GLUT4 in the gastrocnemius muscle mediated by the GPER-PI3K/AKT pathway. Full article

Sheep have been widely used as a model for osteoporosis research. This study aimed to characterise changes in microstructure and composition in lumbar vertebrae L1–L7 and the proximal femur after implementation of a bone loss induction protocol (in this species). A sham control and experimental group (glucocorticoid-treated ovariectomized sheep) were used (n = 6/group), with a study duration up to the 24th postoperative week. Through micro-computed tomography, vertebrae and femoral head trabecular bones from the experimental group presented a consistent decrease in bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) and an increase in trabecular separation (Tb.Sp) and total porosity (p > 0.05). The mineral density of the femoral heads from the experimental group showed a statistically significant decrease (p ˂ 0.05). The entire histomorphometric analysis of the vertebrae in the experimental group showed an increase in cortical porosity (Ct.Po) and a decrease in cortical thickness (Ct.Th) (p ˂ 0.0001 and p ˂ 0.001, respectively). Vertebrae L6 and L7 were the most affected, showing a significant increase in Ct.Po (p < 0.05) and a significant decrease in Ct.Th at the L6 level (p < 0.05). Regarding the trabecular bone at the vertebral level, only L4 showed a significant increase in Tb.Sp (p ˂ 0.05). In the femoral heads’ subchondral cortical layer, the Ct.Po increased significantly and Ct.Th decreased (p < 0.01), and at the trabecular level, the BV/TV, Tb.Th, and Tb.N decreased significantly, while Tb.Sp increased (p < 0.05). In conclusion, the L4, L6 and L7 vertebrae seem the most suitable for further preclinical and translational studies of vertebral augmentation or spinal fusion in this animal model. Full article

The aim of this study was to evaluate structural and micro-architectural changes in the mandible, parietal bone, femur, and tibia in OVX rats at different time periods after ovariectomy. Forty-two 11-month-old female Wistar rats were used. Six rats without surgery were euthanized to serve as a baseline. Eighteen rats were ovariectomized and fed with a calcium-deficient diet, and eighteen animals were used as controls (Ctrls) and fed with a standard diet. Six OVX rats and six Ctrls were euthanized at 3, 6, and 9 months. Qualitative histology and dual-energy X-ray absorptiometry (DXA) were performed. Histological evaluation of bones harvested from the OVX groups revealed trabecular bone reduction, while no significant differences in the cortical bone of OVX and Ctrls were observed. DXA measurements of (1) femoral diaphysis showed a significant decrease in the OVX group compared to the Ctrl groups at 3 (p = 0.041), 6 (p < 0.001), and 9 months (p < 0.001); (2) the proximal tibia showed a significant decrease in the OVX group compared to the Ctrl groups (p < 0.001); (3) parietal bone showed a significant difference between OVX and Ctrls at 6 months (p = 0.012); and (4) the mandible showed no significant differences between the OVX and Ctrl groups. OVX aged rats might present reductions in the density of the femoral diaphysis, proximal tibia, parietal bone, and mandible at different time points. These findings contribute to the field of biomimetics by providing more details for the understanding of age- and hormone-related bone changes in the osteoporotic-like rat model. Such data are critical for the development of biomimetic materials and structures that attempt to simulate natural bone adaptation and deterioration, especially in the context of postmenopausal or osteoporotic conditions. Full article

Background: Osteoporosis is a systemic disease characterized by a progressive decrease in bone density and deterioration of the tissue’s microarchitecture. This results in greater structural fragility and a higher risk of fractures. Osteopenia represents the beginning of the process of decreasing bone density and, if left untreated, can lead to osteoporosis. The objective of this study was to validate an experimental model for establishing cases of decreased bone density that allows for the creation of different levels of severity of mineral loss and changes in bone microstructure. Materials and Methods: Twenty female Wistar rats, 12 weeks old and with a body weight ranging from 300 to 400 g, were used in this study. The animals were randomly distributed into five groups (n = 5 per group): a control group (CG), where the animals were not ovariectomized (OVX), and four experimental groups, where the animals were OVX and euthanized at different times: 30 days (G30), 40 days (G40), 60 days (G60), and 80 days (G80). The animals in the experimental groups underwent bilateral ovariectomy to induce mineral loss. The femurs were collected after the periods established for each group and analyzed using microcomputed tomography (μCT) to determine bone density and count the number of trabeculae. Furthermore, the T-score was calculated for each group. Results: There were significant differences in bone density when comparing all groups, with GC > G30 > G40 > G60 > G80. For the number of trabeculae, GC presented more trabeculae than all other groups. More trabeculae were also observed in G30 when compared to G40, G60, and G80; however, there were no differences between G40, G60, and G80. Regarding the calculation of the T-score by group, osteopenia was observed in G30 (T-score: −2.42) and osteoporosis was observed in G40, G60, and G80 (T-scores: −4.38, −6.34, and −7.71, respectively). Conclusions: The results demonstrate that ovariectomy induces progressive changes in bone structure, with the onset of osteopenia 30 days after ovariectomy and osteoporosis after 40 days in this experimental model. These results may aid future investigations that seek to focus on the specific treatment of osteopenia and/or osteoporosis. Full article

Background/Objective: Palm tocotrienol has bone-protective properties in animal models, yet its underlying mechanism remains unclear. Given osteocytes’ role in bone homeostasis, this research aimed to investigate the effects of palm tocotrienol on the quantity of osteocytes and the expression of osteocyte-specific markers in ovariectomized rats. Methods: Adult female rats (Sprague Dawley; three-month-old; n = 6/group) were randomly divided into baseline, sham control, ovariectomized control, unemulsified palm tocotrienol (UPT), emulsified palm tocotrienol (EPT), and positive control. The baseline group was euthanized without intervention, whereas the sham group underwent a laparotomy procedure in which the ovaries were not excised. The other groups underwent bilateral removal of the ovaries and subsequently received UPT (100 mg/kg/day, 50% vitamin E), EPT (100 mg/kg/day, 25% vitamin E), or a combination of glucosamine sulfate (250 mg/kg/day) and calcium carbonate (1% in drinking water). Control groups were induced with similar gavage stress with olive oil. After 10 weeks, all rats were sacrificed for bone and serum analysis. Results: UPT and EPT significantly increased trabecular osteocyte and total lacunae numbers (p < 0.05 versus ovariectomized control). Both treatments significantly reduced mRNA expression levels of dentin matrix protein-1 (p < 0.05 versus ovariectomized control), whereas sclerostin mRNA expression was unchanged (p > 0.05 versus ovariectomized control). However, neither UPT nor EPT improved circulating or skeletal redox status (p > 0.05 versus ovariectomized control). Conclusions: Palm tocotrienol may support bone health by preserving the quantity of trabecular osteocytes and modulating osteocyte-mediated bone remodeling. Further research is required to elucidate its precise mechanisms. Full article

In the context of osteoporosis closely linked to bone metabolism imbalance caused by estrogen deficiency, total flavonoids of Rhizoma Drynariae (TFRD) exhibit potential anti-osteoporotic activity, yet their multicomponent synergistic mechanism and association with the PI3K/AKT signaling pathway remain unclear. This study aimed to systematically elucidate the molecular mechanisms by which TFRD regulate bone metabolism and improve osteoporosis in ovariectomized (OVX) rats through the PI3K/AKT pathway, integrating network pharmacological predictions with animal experimental validation. Methods involved identifying TFRD’s active components using UPLC/MS-MS, predicting targets with SwissTargetPrediction, constructing a “component-target-disease” network, and performing GO/KEGG enrichment analysis with MetaScape (v3.5). In vivo experiments established an OVX rat model, randomized into sham, OVX, low-/high-dose TFRD, and sim groups, assessing bone mineral density (BMD) and mandibular Micro-CT parameters after 12 weeks. Western blot analyzed PI3K, p-AKT1, and related protein expressions. Results showed the high-dose TFRD group significantly increased BMD, improved trabecular bone quantity and structure, and upregulated PI3K, p-PI3K, and p-AKT1 protein expressions compared to the OVX group. Molecular docking confirmed stable binding energy between core components and PI3K/AKT targets. TFRD may ameliorate estrogen deficiency-induced osteoporosis by activating the PI3K/AKT signaling pathway, inhibiting bone resorption, and promoting osteogenic differentiation, providing pharmacological evidence for multitarget treatment of osteoporosis with traditional Chinese medicine. Full article

Background: Estrogen depletion alters bone mineralization and oxidative stress. Antioxidants like humic acids (HA) may help mitigate bone demineralization and redox imbalances. Thus, this study evaluated the effects of HA on bone mineral composition and oxidative stress markers in an experimental menopause model. Methods: Twenty-four female C57BL/6 mice were divided into four groups (n = 6/group): Sham; Sham + HA; Ovariectomized (OVX); and OVX + HA. The menopause model was induced by bilateral ovariectomy at the beginning of the experiment. HA derived from biomass vermicompost was administered daily by gavage for 28 days. After euthanasia, femurs and fragments of the gastrocnemius muscle, liver, and kidney were collected. Bone elemental composition was analyzed using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Superoxide dismutase (SOD), catalase (CAT), and hydrogen peroxide (H₂O₂) activities were assessed in muscle, renal, and hepatic tissues. Data were analyzed using two-way ANOVA and Bonferroni’s post hoc test. Results: Untreated OVX mice exhibited a significant reduction in femoral calcium content (p < 0.05). However, HA treatment increased calcium levels and improved the Ca/P ratio (p < 0.05). H₂O₂ activity was reduced in the liver and kidney of OVX + HA mice compared to untreated animals (p < 0.05). CAT activity in muscle increased in the OVX + HA group compared to the OVX (p < 0.05). Conclusions: HA treatment improved femoral elemental composition and modulated oxidative stress markers in an experimental menopause model. Full article

This study investigates the cardioprotective effects of intense caloric restriction (ICR) from birth in ovariectomized rats, a model of estrogen deficiency mimicking menopause. Our findings demonstrate that ICR significantly improved both basal and post-ischemic cardiac function, even in the absence of estrogens. The restricted animals exhibited enhanced cardiac contractility and relaxation, particularly after ischemia/reperfusion (I/R) injury, with superior functional recovery compared to control groups. Notably, ICR reduced key cardiometabolic risk factors, including blood pressure, heart rate, and adiposity, while improving glucose tolerance and insulin sensitivity. Additionally, while mitochondrial biogenesis remained unaffected, ICR preserved mitochondrial integrity by reducing the number of damaged mitochondria. This was linked to a reduction in oxidative stress, as evidenced by lower reactive oxygen species (ROS) production in the hearts of restricted animals. These results suggest that ICR offers a protective effect against cardiovascular dysfunction induced by estrogen depletion, potentially through enhanced antioxidant defenses and mitochondrial protection. Full article

The photoperiod has been considered to be a key environmental factor in sheep reproduction, and some studies have shown that the thyroid gland plays an important role in mammalian reproduction, but the molecular mechanism is still unclear. In this study, we used the artificial-light-controlled, ovariectomized, and estradiol-treated model (OVX + E2 model); healthy and consistent 2–3-year-old Sunite multiparous ewes were collected; and thyroids were collected for testing, combined with RNA-seq technology and bioinformatics analysis, to analyze the effects of different photoperiods (long photoperiod treatment for 42 days, LP42; short photoperiod treatment for 42 days, SP42; SP42 transferred to LP42, SPLP42) on the variations in the miRNA profiles of the thyroid gland. A total of 105 miRNAs were differentially expressed in the thyroid gland, most of which were new miRNAs. Through GO and KEGG enrichment analysis, the results showed that the photoperiod response characteristics of Sunite ewes were affected by Olfactory transduction, Wnt signaling pathways, and Apelin signaling pathways. A different illumination time may have a certain influence on the downstream of these pathways, which leads to the change in animal estrus state. In addition, lncRNA-mRNA-miRNA network analysis revealed the target binding sites of identified miRNAs in DE-circRNA and DE-mRNA, such as Novel_369, Novel_370, Novel_461, and so on. The results of this study will provide some new insights into the function of miRNA and the changes in sheep thyroid glands under different photoperiods. Full article

Background: Osteoporosis is a metabolic bone disease with a high mortality rate due to non-traumatic fractures. The risk of osteoporosis is increasing globally due to an increasing aging population. Current therapies are limited to delaying disease progression. Recently, the need to discover foods with osteogenic activity for the prevention and treatment of osteoporosis has been emphasized. We focused on bone formation via osteoblast differentiation, considering bone formation and resorption during bone homeostasis. Rubus tozawae Nakai ex J. Y. Yang (RL, Geoje raspberry) is a deciduous subshrub that has been traditionally eaten for its fruit. Methods and Results: We identified the third subfraction of n-hexane fraction (RL-Hex-NF3) of RL, an endemic Korean plant with osteogenic activity, which increased bone density in ovariectomized mice, a representative animal model of osteoporosis, via the depletion of female hormones, which resulted from the increase in the osteoblast population. RL-Hex-NF3 induced osteoblast differentiation and the expression of osteogenic markers in MC3T3-E1 pre-osteoblasts. Seven compounds were identified from RL-Hex-NF3 using NMR spectroscopy. Of these, three compounds, namely, 3β-hydroxy-18α,19α-urs-20-en-28-oic acid, betulinic acid, and (1S,6R,7S)-muurola-4,10(14)-diene-15-ol, showed strong osteogenic activity. Conclusions: RL-Hex-NF3 and its compounds suppress bone loss via their osteogenic properties, suggesting that they could be a potent candidate to treat osteoporosis. Full article

Background/Objectives: In Southeast Asia, the traditional use of young coconut (Cocos nucifera L.) juice (YCJ) by women to alleviate postmenopausal symptoms suggests potential estrogenic properties. However, few studies explore the impact of YCJ on pathologies associated with estrogen deficiency in postmenopausal animal models. This study examines the impact of YCJ supplementation on memory impairment and depression-like behavior in ovariectomized (Ovx) rats. Methods: Ten-week-old female rats underwent either a sham operation (Sham) or bilateral Ovx. The rats in the Ovx + YCJ group received 5×-concentrated YCJ by gavage at a dose of 15 mL/kg body weight. Twelve weeks later, the Morris water maze and forced swim tests were used to evaluate hippocampus-dependent spatial memory and depression-like behavior, respectively. Results: The Ovx rats displayed significant memory impairment (p < 0.05) and depression-like behaviors (p < 0.05), while the memory performance in the rats in the Ovx + YCJ group resembled that of the Sham rats. However, the administration of YCJ did not result in the improvement of depression-like behavior. Conclusions: These findings suggest that YCJ consumption may help ameliorate memory impairment in postmenopausal women. Full article

Osteoporosis is a bone-debilitating disease, demonstrating a higher prevalence in post-menopausal women due to estrogen deprivation. One of the main mechanisms underlying menopause-related bone loss is oxidative stress. S-allylmercapto-N-acetylcysteine (ASSNAC) is a nuclear factor erythroid 2-related factor 2 (Nrf2) activator and cysteine supplier, previously shown to have anti-oxidation protective effects in cultured cells and animal models. Here, we studied the therapeutic potential of ASSNAC with and without Alendronate in ovariectomized (OVX) female mice. The experimental outcome included (i) femur and L3 lumbar vertebra morphometry via Micro-Computed Tomography (μCT); (ii) bone remodeling (formation vs. resorption); and (iii) oxidative stress markers in bone marrow (BM) cells. Four weeks after OVX, there was a significant bone loss that remained evident after 8 weeks, as demonstrated via µCT in the femur (cortical and trabecular bone compartments) and vertebra (trabecular bone). ASSNAC at a dose of 50 mg/Kg/day prevented bone loss after the four-week treatment but had no significant effect after 8 weeks, while ASSNAC at a dose of 20 mg/Kg/day significantly protected against bone loss after 8 weeks of treatment. Alendronate prevented ovariectomy-induced bone loss, and combining it with ASSNAC further augmented this effect. OVX mice demonstrated high serum levels of both C-terminal cross-linked telopeptides of type I collagen (CTX) (bone resorption) and procollagen I N-terminal propeptide (P1NP) (bone formation) after 2 weeks, and these returned to control levels after 8 weeks. Alendronate, ASSNAC and their combination decreased CTX and increased P1NP. Alendronate induced oxidative stress as reflected by decreased glutathione and increased malondialdehyde (MDA) levels, and combining it with ASSNAC partially attenuated these changes. These results portray the therapeutic potential of ASSNAC for the management of post-menopausal osteoporosis. Furthermore, ASSNAC ameliorates the Alendronate-associated oxidative stress, suggesting its potential to prevent Alendronate side effects as well as improve its bone-protective effect. Full article

Osteoarthritis (OA) persistently activates nociceptors, leading to chronic pain, which is often accompanied by the comorbid development of emotional impairments (anxiety and depression), an effect associated with microgliosis. Baccharis dracunculifolia DC (Asteraceae), a Brazilian edible plant, is an important source of active compounds with anti-inflammatory abilities. Thus, we evaluated its ability to reverse OA-induced nociceptive and emotional-like impairments in osteoarthritic ovariectomized female rats using the kaolin/carrageenan (K/C) model. Four weeks after OA induction, mechanical hyperalgesia was confirmed, and the treatment started. Control animals (SHAMs) were treated with phosphate-buffered saline (PBS), while arthritic animals (ARTHs) either received PBS or B. dracunculifolia 50 mg/kg (Bd50) and 100 mg/kg (Bd100), via gavage, daily for five weeks. At the end of the treatment, anxiety-like behavior was assessed using the Open Field Test (OFT), anhedonia was assessed using the Sucrose Preference Test (SPT), and learned helplessness was assessed using the Forced Swimming Test (FST). After occision, microglia were stained with IBA-1 and quantified in brain sections of target areas (prefrontal cortex, amygdala, and periaqueductal grey matter). Treatment with B. dracunculifolia extract reversed OA-induced mechanical hyperalgesia and partly improved depressive-like behavior in OA animals’ concomitant to a decrease in the number of M1 microglia. Our findings suggest that B. dracunculifolia extracts can potentially be used in the food industry and for the development of nutraceuticals and functional foods. Full article

Obesity induced by a high-fat (HF) diet increases bone resorption and/or decreases bone formation, resulting in reduced bone mass and strength in various animal models. Studies showed that Ca intake is a modifiable factor for osteoporosis and obesity. This study investigated whether Ca deficiency affects bone structure and adiposity in ovariectomized (OVX) rats fed a HF diet. We hypothesized that Ca deficiency further decreases bone mass and increases fat mass in HF-fed OVX rats. Forty-seven OVX at 6-month-old were randomly assigned to four groups in a 2 × 2 factorial design: normal-fat (NF, 10% fat as energy) or HF (45% fat as energy) diet with either low Ca (LC, 1 g/4057 kcal) or normal Ca (NC, 6 g/4057 kcal). In addition, 12 sham-operated rats at 6 months old were fed a NFNC diet as a control for the OVX procedure. Rats were fed the respective diet for 4 months. Dietary Ca content did not affect body weight, fat mass, lean mass, food intake, energy intake, and serum cytokines. Compared to NC, LC resulted in lower tibial bone volume/total volume (BV/TV, p < 0.01), connectivity density (p < 0.01), trabecular number (Tb.N, p = 0.01), bone mineral density (BMD, p < 0.01), and femur weight (p < 0.01), femur content of Ca (p < 0.01), Cu (p = 0.03), Zn (p < 0.01), and greater trabecular separation (Tb.Sp, p < 0.01) at proximal tibia indicating bone structure deterioration. Compared to rats on the NF diet, animals fed the HF had lower BV/TV (p = 0.03) and Tb.N (p < 0.01) with greater body weight (p < 0.01), fat mass (p < 0.01), Tb.Sp (p = 0.01), the content of Ca, Cu, and Zn in the femur, and serum leptin (p < 0.01). There were no significant interactions between Ca and fat for body composition and bone structural parameters. Compared to Sham, OVX resulted in greater body weight and fat mass. The trabecular bone structure of the tibia, but not the cortical bone, was significantly impaired by the OVX procedure. These data indicate that inadequate Ca intake and a high-fat diet have independent negative effects on bone structure and that Ca deficiency does not affect adiposity in OVX rats. Full article