Osteoporosis Model Research Articles

Total flavonoids of Rhizoma drynariae influence ferroptosis in osteoblasts via miR-205-5p/GPX4 axis

Purpose: This research investigated the biological effects of total flavonoids of Rhizoma Drynariae (TFRD) on osteoporosis in mice.Methods: Mice were subjected to bilateral ovariectomy (OVX) to generate the osteoporosis model used, which was then intragastrically administered TFRD daily at a dose of 75 mg/kg. Bone loss was examined histologically using H&E staining. Moreover, erastin-treated primary osteoblasts were used to further analyze the effect of TFRD on ferroptosis. Reactive oxygen species (ROS), ferrous iron level, and CCK-8 method were employed to determine the protective influence of TFRD against ferroptosis in erastin-treated osteoblasts. The relationship between microRNA-205-5p (miR-205-5p) and glutathione peroxidase 4 (GPX4) was determined using luciferase assay.Results: TFRD treatment inhibited OVX-induced bone mass loss, downregulated ferrous ion content, and increased the level of GPX4 in vivo (p < 0.01). Besides, TFRD treatment inhibited erastin-induced increases in ROS level and ferrous iron level, and promoted cell viability in vitro (p < 0.01). Moreover, TFRD increased GPX4 protein expression level (p < 0.01). Results from gain and loss experiments showed that GPX4 increased cell viability, and reduced ferrous ion and ROS levels in erastin-induced osteoblasts (p < 0.01, p < 0.001, respectively). Furthermore, miR-205-5p directly targeted GPX4 and negatively regulated GPX4 expression (p < 0.01, p < 0.001, respectively). Upregulation of GPX4 reversed the effect of miR-205-5p overexpression on cell viability, and reduced ferrous iron level and ROS levels in osteoblasts significantly.Conclusion: TFRD may serve as an inhibitor of osteoblast ferroptosis during osteoporosis formation by down-regulating the expression of miR-205-5p which directly targets GPX4 in mouse osteoblasts. These findings indicate the therapeutic potential and underlying mechanism of action of TFRD.

Bone-Targeted Delivery of Cell-Penetrating-RUNX2 Fusion Protein in Osteoporosis Model.

The onset of osteoporosis leads to a gradual decrease in bone density due to an imbalance between bone formation and resorption. To achieve optimal drug efficacy with minimal side effects, targeted drug delivery to the bone is necessary. Previous studies have utilized peptides that bind to hydroxyapatite, a mineral component of bone, for bone-targeted drug delivery. In this study, a hydroxyapatite binding (HAB) tag is fused to 30Kc19α-Runt-related transcription factor 2 (RUNX2) for bone-targeting. This recombinant protein can penetrate the nucleus of human mesenchymal stem cells (hMSCs) and act as a master transcription factor for osteogenesis. The HAB tag increases the binding affinity of 30Kc19α-RUNX2 to mineral deposition in mature osteoblasts and bone tissue, without affecting its osteogenic induction capability. In the osteoporosis mouse model, intravenous injection of HAB-30Kc19α-RUNX2 results in preferential accumulation in the femur and promotes bone formation while reducing toxicity in the spleen. These findings suggest that HAB-30Kc19α-RUNX2 may be a promising candidate for bone-targeted therapy in osteoporosis.

Lactobacillus Reuteri 6475 Prevents Bone Loss in a Clinically Relevant Oral Model of Glucocorticoid-Induced Osteoporosis in Male CD-1 Mice.

Glucocorticoids (GCs) are commonly used anti-inflammatory medications with significant side effects, including glucocorticoid-induced osteoporosis (GIO). We have previously demonstrated that chronic subcutaneous GC treatment in mice leads to gut barrier dysfunction and trabecular bone loss. We further showed that treating with probiotics or barrier enhancers improves gut barrier function and prevents GIO. The overall goal of this study was to test if probiotics could prevent GC-induced gut barrier dysfunction and bone loss in a clinically relevant oral-GC model of GIO. Eight-week-old male CD-1 mice were treated with vehicle or corticosterone in the drinking water for 4 weeks and administered probiotics Lactobacillus reuteri ATCC 6475 (LR 6475) or VSL#3 thrice weekly via oral gavage. As expected, GC treatment led to significant gut barrier dysfunction (assessed by measuring serum endotoxin levels) and bone loss after 4 weeks. Serum endotoxin levels significantly and negatively correlated with bone volume. Importantly, LR 6475 treatment effectively prevented both GC-induced increase in serum endotoxin and trabecular bone loss. VSL#3 had intermediate results, not differing from either control or GC-treated animals. GC-induced reductions in femur length, cortical thickness, and cortical area were not affected by probiotic treatment. Taken together, these results are the first to demonstrate that LR 6475 effectively prevents the detrimental effects of GC treatment on gut barrier, which correlates with enhanced trabecular bone health in an oral mouse model of GIO. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Method for obtaining supramolecular complex based on 3-ohypyridine derivatives and its application for correction of osteoporosis

Introduction: Currently, there are no safe and ideal medicines for the prevention and treatment of oophorectomy-induced osteoporosis. The development of an effective pharmacotherapy for hypoestrogen-induced osteoporosis is an important task of pharmacology. Materials and Methods: A new supramolecular complex (composition №1) was obtained on the basis of 3-hydroxypyridine derivatives: 2-ethyl-6-methyl-3-hydroxypyridinium 3-pyridinocarbonoate and 2-ethyl-6-methyl-3-hydroxypyridinium N-acetyl-6-aminohexanoate in a ratio of 1:3 by topochemical synthesis. The study of the osteoprotective activity of the supramolecular complex at a dose of 50 mg/kg was performed on 60 white female rats of the Wistar line on a model of hypoestrogen-induced osteoporosis. The effectiveness of the osteoprotective activity of the complex was evaluated on the 57th day of the experiment. Results and Discussion: The new supramolecular complex (composition №1) has osteoprotective activity, which is expressed in improving the indicators of X-ray and histomorphological samples. Oral administration of composition №1 at a dose of 50 mg/kg led to an increase in bone density to values of 2.55±0.02 g/cm3, which is 1.3 times higher than in the control group 1.92±0.01 g/cm3 (p≤0.05) and reduce bone resorption by improving cortical and trabecular bone structures. Conclusion: The obtained data characterize the prospects of studying composition №1 for the correction and prevention of hypoestrogen-induced osteoporosis. Graphical Abstract

The miR-224-5p/SIRT3/AMPK/mTOR axis is involved in the melatonin-mediated inhibition of glucocorticoid-induced osteoporosis by activating autophagy.

Melatonin has been shown to exert an inhibitory effect on osteoporosis. This study investigates the function of the miR-224-5p/SIRT3/AMPK/mTOR axis in melatonin-mediated effects against osteoporosis. Human bone marrow mesenchymal stem cells (hBMSCs) were treated with glucocorticoid dexamethasone to induce an in vitro osteoporosis model. After melatonin treatment, miR-224-5p and SIRT3 levels were measured by RT‒PCR. Transmission electron microscopy and immunofluorescence were conducted for evaluating autophagy. Western blotting was carried out to determine the expression of osteogenesis-related proteins (Runx2, OSX, OPN, and OCN), SIRT3-AMPK-mTOR axis, and autophagy-related markers (LC3 and p62). Alizarin red staining was used to measure matrix mineralization. The data showed that melatonin inhibited dexamethasone-induced osteoporosis in vitro, and enhanced autophagic levels (as indicated by increased LC3 puncta, LC3II/I ratio, and autophagic vacuoles). In terms of the mechanisms, melatonin decreased miR-224-5p expression and increased SIRT3. SRIT3 was shown to be a direct target of miR-224-5p. miR-224-5p upregulation or SIRT3 downregulation reversed the effects of melatonin on osteoporosis and suppressed autophagy. Additionally, miR-224-5p inhibited SIRT3 expression and AMPK pathway activation. In summary, we discovered that melatonin suppressed glucocorticoid-induced osteoporosis and autophagy inhibition via the miR-224-5p/SIRT3/AMPK/mTOR axis.

Protective effect and possible mechanisms of resveratrol in animal models of osteoporosis: A preclinical systematic review and meta-analysis.

Resveratrol (RES) has extensively been utilized to treat osteoporosis (OP) in animal models. However, the anti-OP effects of RES have not been tested during clinical application due to the lack of evidence and poor knowledge of the underlying mechanisms. Moreover, there is little preclinical evidence to support the use of RES in the management of OP. In the present paper, we conducted a preclinical systematic review and meta-analysis to assess the efficacy of RES in animal OP models. The potential mechanisms underlying the efficacy of RES against OP were summarized. The online databases PubMed, CNKI, EMBASE, Wanfang, Web of Science, Chinese Biomedical Literature, Cochrane Library, and Chinese VIP were retrieved from inception to December 2021. The CAMARADES 10-item quality checklist was utilized to assess the risk of bias of the included studies. STATA 12.0 software was employed to analyze the data. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. Thirteen studies containing 248 animals were included yielding a mean risk of bias score of 5.54 (range 4-7). The pooled estimates showed that the administration of RES could significantly elevate the bone mineral density (BMD) both at femur (SMD = 2.536; 95% CI = 1.950-3.122; p < 0.001) and lumbar spine (SMD = 1.363; 95% CI = 0894-1.832; p < 0.001), bone volume over total volume (BV/TV) (SMD = 2.543; 95% CI = 2.023-3.062; p < 0.001), trabecular linear density (Tb.N) (SMD = 2.724; 95% CI = 2.186-3.262; p < 0.001) and trabecular thickness (Tb.Th) (SMD = 1.745; 95% CI = 1.294-2.196; p < 0.001), while serum phosphorus (S-P) (SMD = -2.168; 95% CI = -2.753 to -1.583; p < 0.001) and trabecular separation (Tb.Sp) (SMD = -2.856; 95% CI = -4.218 to -1.494; p < 0.001) were significantly reduced in animal OP models. No significant change in serum calcium (S-Ca) (SMD = -2.448; 95% CI = -5.255-0.360; p = 0.087) was observed after RES treatment. Furthermore, RES could significantly improve the bone biomechanical indexes: bone maximum load (BML) (SMD = 2.563; 95% CI = 1.827-3.299; p < 0.001) and connectivity density (Conn.D) (SMD = 1.512; 95% CI = 0.909-2.116; p < 0.001) and decrease the structural model index (SMI) (SMD = -2.522; 95% CI = -3.243 to -1.801; p < 0.001). Overall, the present study revealed that RES has huge prospects as a medicine or dietary supplement for the clinical treatment of OP. High-quality studies with stringent designs and larger sample sizes are warranted to substantiate our conclusion.

Effects of ligandrol as a selective androgen receptor modulator in a rat model for osteoporosis.

The selective androgen receptor modulator ligandrol (LGD-4033 or VK5211) has been shown to improve muscle tissue. In the present study, the effect of ligandrol on bone tissue was investigated in ovariectomized rat model. Three-month-old Sprague Dawley rats were either ovariectomized (OVX, n = 60) or left intact (NON-OVX, n = 15). After 9weeks, OVX rats were divided into four groups: untreated OVX (n = 15) group and three OVX groups (each of 15 rats) treated with ligandrol orally at doses of 0.03, 0.3, or 3mg/kg body weight. After five weeks, lumbar vertebral bodies (L), tibiae, and femora were examined using micro-computed tomographical, biomechanical, ashing, and gene expression analyses. In the 3-mg ligandrol group, bone structural properties were improved (trabecular number: 38 ± 8 vs. 35 ± 7 (femur), 26 ± 7 vs. 22 ± 6 (L), 12 ± 5 vs. 6 ± 3 (tibia) and serum phosphorus levels (1.81 ± 0.17 vs.1.41 ± 0.17mmol/l), uterus (0.43 ± 0.04 vs. 0.11 ± 0.02g), and heart (1.13 ± 0.11 vs. 1.01 ± 0.08g) weights were increased compared to the OVX group. Biomechanical parameters were not changed. Low and medium doses did not affect bone tissue and had fewer side effects. Body weight and food intake were not affected by ligandrol; OVX led to an increase in these parameters and worsened all bone parameters. Ligandrol at high dose showed a subtle anabolic effect on structural properties without any improvement in biomechanical properties of osteoporotic bones. Considering side effects of ligandrol at this dose, its further investigation for the therapy of postmenopausal osteoporosis should be reevaluated.

Biomechanical evaluation of a novel minimally invasive pedicle bone cement screw applied to the treatment of Kümmel's disease in porcine vertebrae.

Background and objective: Treatment of Kümmel's Disease (KD) with pure percutaneous kyphoplasty carries a greater likelihood of bone cement displacement due to hardened bone and defect of the peripheral cortex. In this study, we designed a novel minimally invasive pedicle bone cement screw and evaluate the effectiveness and safety of this modified surgical instruments in porcine vertebrae. Methods: 18 mature porcine spine specimens were obtained and soaked in 10% formaldehyde solution for 24h. 0.5000mmol/L EDTA-Na2 solution was used to develop in vitro osteoporosis models of porcine vertebrae. They were all made with the bone deficiency at the anterior edge of L1. These specimens were randomly divided into 3 groups for different ways of treatment: Group A: pure percutaneous kyphoplasty (PKP) group; Group B: unilateral novel minimally invasive pedicle bone cement screw fixation combined with PKP group; Group C: bilateral novel minimally invasive pedicle bone cement screw fixation combined with PKP group. The MTS multi-degree of freedom simulation test system was used for biomechanical tests, including axial loading of 500N pressure, range of motion (ROM) in flexion, extension, left/right lateral bending, and left/right axial rotation at 5Nm, and the displacement of bone cement mass at maximum angles of 5° and 10°. Result: The three groups were well filled with bone cement, no leakage or displacement of bone cement was observed, and the height of the vertebrae was higher than pre-operation (p < 0.05). In the left/right axial rotation, the specimens were still significantly different (p < 0.05) from the intact specimens in terms of ROM after PKP. In other directions, ROM of all group had no significant difference (p < 0.05) and was close to the intact vertebrae. Compared with PKP group, the relative displacement of bone cement in groups B and C was smaller (p < 0.05). Conclusion: In the in vitro animal vertebral models, the treatment of KD with the placement of novel pedicle minimally invasive bone cement screw combined with PKP can effectively restore the vertebral height, improve the stability of the affected vertebra and prevent the displacement of bone cement. Biomechanically, there is no significant difference between bilateral and unilateral fixation.

T2*-corrected Q-Dixon and reduced-FOV diffusion kurtosis imaging (DKI) parameters: correlation with QCT-derived bone mineral density (BMD) and ability to identify abnormal BMD and osteoporosis in postmenopausal women.

Bone marrow fat increases when the bone volume decreases. The composition of the bone marrow microenvironment can also become altered. Assessments of bone marrow fat and bone marrow structural heterogeneity have the potential to predict abnormal bone mineral density (BMD) and osteoporosis. This study aimed to investigate the diagnostic performance of T2*-corrected Q-Dixon and reduced-field-of-view (FOV) diffusion kurtosis imaging (DKI) parameters in determining abnormal BMD and osteoporosis in postmenopausal women. In this prospective study, the individuals who were eligible for inclusion included postmenopausal women (over 50-year-old) with suspected osteoporosis based on experiencing low back pain. This mono-center study was conducted in tertiary care in China. All of the patients were recruited by using the consecutive sampling method. Subjects who underwent T2*-corrected Q-Dixon and reduced-FOV DKI sequences were enrolled. Fat fraction (FF), T2*, mean kurtosis (MK), and mean diffusivity (MD) values were measured on L1, L2, and L3 vertebral bodies. Quantitative computed tomography (QCT) examinations served as the reference standard. All of the subjects were divided into three groups: normal (BMD >120 mg/cm3), osteopenia (BMD 80-120 mg/cm3), and osteoporosis (BMD <80 mg/cm3). One-way analysis of variance, correlation coefficient analysis, and receiver operating characteristic curve analysis were performed. Among all of the enrolled subjects, 52 were in the normal group, 51 were in the osteopenia group, and 52 were in the osteoporosis group. There were significant differences in FF, T2*, MK, and MD values between the three groups (P<0.001, P<0.001, P<0.001, and P=0.003, respectively). FF, T2*, and MK values exhibited significant negative correlations with BMD values (r=-0.739, P<0.001; r=-0,676, P<0.001; and r=-0.626, P<0.001, respectively). Excellent discriminatory capacity was observed in the Q-Dixon [area under the curve (AUC): 0.976, 95% confidence interval (CI): 0.955-0.997] differentiation between normal and abnormal BMD subjects. It was significantly better than the DKI (AUC: 0.812, 95% CI: 0.741-0.882) parameter combination (P<0.001), whereas the DKI model (AUC: 0.825, 95% CI: 0.739-0.910) performed comparably to the Q-Dixon model (AUC: 0.798, 95% CI: 0.710-0.886) for screening osteoporosis (P=0.57). FF and T2* values measured by using T2*-corrected Q-Dixon, as well as MK and MD values measured by using reduced-FOV DKI, may serve as potential imaging biomarkers in assessing abnormal BMD and osteoporosis in postmenopausal women.

Psoralen prevents the inactivation of estradiol and treats osteoporosis via covalently targeting HSD17B2.

Psoralea corylifolia L. seeds (P. corylifolia), popularly known as Buguzhi in traditional Chinese medicine, are often used to treat osteoporosis in China. Psoralen (Pso) is the key anti-osteoporosis constituent in P. corylifolia, however, its targets and mechanism of action are still unclear. The purpose of this study was to explore the interaction between Pso and 17-β hydroxysteroid dehydrogenase type 2 (HSD17B2), an estrogen synthesis-related protein that inhibits the inactivation of estradiol (E2) to treat osteoporosis. Tissue distribution of Pso was analyzed by in-gel imaging after oral administration of an alkynyl-modified Pso probe (aPso) in mice. The target of Pso in the liver was identified and analyzed using chemical proteomics. Co-localization and cellular thermal shift assays (CETSA) were used to verify the key action targets. To detect the key pharmacophore of Pso, the interaction of Pso and its structural analogs with HSD17B2 was investigated by CETSA, HSD17B2 activity assay, and in-gel imaging determination. Target competitive test, virtual docking, mutated HSD17B2 activity, and CETSA assay were used to identify the binding site of Pso with HSD17B2. A mouse model of osteoporosis was established by ovariectomies, and the efficacy of Pso in vivo was confirmed by micro-CT, H&E staining, HSD17B2 activity, and bone-related biochemical assays. Pso regulated estrogen metabolism by targeting HSD17B2 in the liver, with the α, β-unsaturated ester in Pso being the key pharmacophore. Pso significantly suppressed HSD17B2 activity by irreversibly binding to Lys236 of HSD17B2 and preventing NAD+ from entering the binding pocket. In vivo studies in ovariectomized mice revealed that Pso could inhibit HSD17B2 activity, prevent the inactivation of E2, increase levels of endogenous estrogen, improve bone metabolism-related indices, and play a role in anti-osteoporosis. Pso covalently binds to Lys236 of HSD17B2 in hepatocytes to prevent the inactivation of E2, thereby aiding in the treatment of osteoporosis.

Melatonin is more effective on bone metabolism when given at early night than during the day in ovariectomized rats

Melatonin has diverse effects, and has been reported to promote bone formation in addition to regulating the sleep–wake cycle. In the present study, we investigated the effects of melatonin on bone metabolism using ovariectomized (OVX) rats; a model of postmenopausal osteoporosis. Here, we focused on the differences in bone formation when melatonin was subcutaneous injected at day or early night. The OVX rats were injected with melatonin once daily (0.8 or 8 mg/head) between 11:00 to 14:00 or 18:00 to 19:30 for the day or early night, respectively, for six weeks. After completion of the injection, the femur and tibia in the OVX rats were dissected under general anesthesia and examined by quantitative computed tomography (pQCT) and histological analysis, respectively. Interestingly, the trabecular bone mineral density in the femur metaphysis of the OVX rats receiving 8 mg/head melatonin at early night was higher than those receiving melatonin during the day and they recovered to a similar level as the rats with sham treatment. In the diaphysis, the pQCT analysis results indicated that there was no significant difference in bone mineral density between the day and early night melatonin-injected OVX rats. Histological analysis of the secondary trabecular bone in the tibia of the OVX rats, revealed that the bone matrix area of the group receiving 8 mg/head melatonin at early night was higher compared with that of the day group and had a significant difference compared with OVX treatment rats. Taken together, the subcutaneous melatonin injection in OVX rats at early night was found to promote trabecular bone formation better than melatonin injection during the day. The timing of melatonin injection is a crucial factor when examining the influence of bone metabolism.

D-Pinitol Ameliorated Osteoporosis via Elevating D-chiro-Inositol Level in Ovariectomized Mice.

A natural sugar alcohol, D-pinitol, has been reported to be a potential compound for osteoporosis treatment via inhibiting osteoclastgenesis. However, research on the effects of pinitol on osteoporosis in vivo is still limited. The present study investigated the protective effects of pinitol on ovariectomized mice and attempted to elucidate this mechanism in vivo. Four-week-old female ovariectomized ICR mice were employed as a postmenopausal osteoporosis model and treated with pinitol or estradiol (E2) for 7 wk. Thereafter, serum calcium content, phosphorus content, tartrate-resistant acid phosphatase (TRAcP) and bone-specific alkaline phosphatase activity (BALP) were measured. Bilateral femurs were isolated, and bone marrow protein was collected through centrifuge. Dry femurs were weighed, while femur length, cellular bones, and bone mineral content were measured. D-chiro-Inositol (DCI) and myo-inositol (MI) content in serum and bone marrow was measured by GC-MS. At the end of experiment, the serum BALP and TRAcP activities of the OVX mice were suppressed significantly by treatment with either pinitol or E2. Femur weight, cellular bone rate, Ca and P content were improved by pinitol or E2. The DCI content of the serum of OVX decreased significantly, although it recovered to some extent after pinitol treatment. Pinitol significantly increased the ratio of DCI to MI in serum or bone marrow protein in the observed OVX mice. Besides, pinitol had no significant effects on osteoblast viability and differentiation. The present results showed that continuous pinitol intake exerts potent anti-osteoporosis activity via elevating DCI content in serum and bone marrow in OVX mice.

Treatment of osteoporosis using a selective androgen receptor modulator ostarine in an orchiectomized rat model

PurposeThe selective androgen receptor modulator ostarine has been shown to have advantageous effects on skeletal tissue properties, reducing muscle wasting and improving physical function in males. However, data on effects in male osteoporosis remain limited. In this study, the effects of ostarine on osteoporotic bone were evaluated in a rat model of male osteoporosis and compared with those of testosterone treatments.MethodsEight-month-old male Sprague-Dawley rats were either non-orchiectomized to serve as a healthy control (Non-Orx, Group 1) or orchiectomized (Orx, Groups 2–6) and then grouped (n = 15/group): (1) Non-Orx, (2) Orx, (3) Ostarine Therapy, (4) Testosterone Therapy, (5) Ostarine Prophylaxis and (6) Testosterone Prophylaxis. Prophylaxis treatments started directly after orchiectomy and continued for 18 weeks, whereas Therapy treatments were initiated 12 weeks after Orx. Ostarine and Testosterone were applied orally at daily doses of 0.4 and 50 mg/kg body weight, respectively. The lumbar vertebral bodies and femora were analyzed using biomechanical, micro-CT, ashing, and gene expression analyses.ResultsOstarine Prophylaxis showed positive effects in preventing osteoporotic changes in cortical and trabecular bone (femoral trabecular density: 26.01 ± 9.1% vs. 20.75 ± 1.2% in Orx and in L4: 16.3 ± 7.3% vs 11.8 ± 2.9% in Orx); biomechanical parameters were not affected; prostate weight was increased (0.62 ± 0.13 g vs 0.18 ± 0.07 g in Orx). Ostarine Therapy increased solely the cortical density of the femur (1.25 ± 0.03 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); other bone parameters remained unaffected. Testosteron Prophylaxis positively influenced cortical density in femur (1.24 ± 0.05 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); Test. Therapy did not change any bony parameters.ConclusionOstarine Prophylaxis could be further investigated as a preventative treatment for male osteoporosis, but an androgenic effect on the prostate should be taken into consideration, and combination therapies with other anti-osteoporosis agents could be considered.

Integrated Dose-Effect Relationship of Near-Infrared Light-Emitting Diode Light on Bone Regeneration in Disuse Osteoporosis Rats.

Objective: To examine the integrated dose-effect relationship of near-infrared (NIR) light-emitting diode (LED) light therapy in promoting bone defect repair in the rat model for osteoporosis (OP). Background: Low-intensity laser therapy has been shown to promote bone regeneration in OP rats. However, its integrated dose-effect relationship is not clear. Methods: Twenty-week-old male Sprague-Dawley rats were randomly assigned to 11 groups: (1) no-treatment control group (C group), (2) tail suspension (TS)-induced disuse OP experimental group (TS-OP group), and (3) OP rats with LED light treatment at nine dosages (L1-L9 groups). The tail of the rat was tied and suspended on the beam of the cage to suspend their hind limbs to induce bone loss for 4 or 7 weeks. The rats were then released and returned to their regular positions. An NIR LED at 810 nm was used on the bilateral hind limbs daily for 4 weeks. The C group rats were not given any treatment. The TS-OP group rats were subjected to identical procedures with L groups, with the exception that the light power was not turned on. After the experiment, the dual-energy X-rays or the microcomputed tomography scan analysis was performed to evaluate bone tissue status. Data analysis was done using SPSS and the health scale. Results: The trabecular thickness, trabecular number, bone volume/total volume, and connectivity density of cancellous bone and the biomechanical properties of femur in light groups were significantly increased compared with the TS-OP group, while the trabecular separation and structure model index were significantly decreased. Conclusions: NIR LED light therapy may promote trabecular bone repair of TS-OP rats. Light intensity influences photobiomodulation. In our dose levels, the greater the light intensity, usually the more effective.

Leptin and melatonin's effects on OVX rodents' bone metabolism.

This study aims to examine the effects of leptin and melatonin intervention on bone metabolism in ovariectomize (OVX) rodents, as well as their potential mechanisms of action. Prepare an OVX model of osteoporosis in rodents and validate the model by collecting bilateral tibia samples for Micro-CT scanning and histological analysis. A control group of normal size, the OVX group, the OVX+Sema4D (Semaphorin 4D) group, the OVX+Sema4D+Leptin group, the OVX+Sema4D+ Melatonin(MT) group and the OVX+Sema4D+Leptin+ MT group were the experimental groups. Adenovirus vector construction and tibial medullary injection validation were conducted in accordance with the aforementioned experimental groups. Four groups of rats were injected with the Sema4D overexpression adenovirus vector into the tibial medullary cavity, and two groups were injected with the Leptin overexpression adenovirus vector. The repair of osteoporosis was observed using micro-CT and histological analysis. Immunohistochemical detection of bone morphogenetic protein-2 (BMP-2) expression in bone tissue was employed to ascertain the amount of osteoclasts in the upper tibial metaphysis, utilizing TRAP(tartrate-resistant acid phosphatase) staining. Increased levels of BV/TV, Tb.N, BMD, and BMC were seen in the OVX+ Sema4D+Leptin, OVX+ Sema4D+MT, and OVX+ Sema4D+Leptin+ MT groups compared to the OVX group, whereas Tb. Sp levels were lowered. When compared to the Sema4D overexpression group, the trabecular bone structure of the OVX + Sema4D + Leptin, OVX + Sema4D + MT, and OVX + Sema4D + Leptin + MT groups is largely intact, tends to be closer, and the amount of trabecular bone increases. The OVX + Sema4D + Leptin + MT group in particular.The expression of BMP-2 was dramatically upregulated (p<0.05), the number of TRAP-stained osteoclasts was significantly reduced (p<0.05), and BALP(bone-derived alkaline phosphatase) and TRAP-5b(tartrate-resistant acid phosphatase-5b) activities were significantly downregulated (p<0.05). In rats with osteoporosis, leptin and melatonin can be seen to augment the trabecular microstructure of the bone, augment bone growth, diminish trabecular harm, and mend the bone. The combined effect is more powerful.

Effect of fermentation using different lactic acid bacteria strains on the nutrient components and mineral bioavailability of soybean yogurt alternative.

Analysis of the composition of yogurt alternatives (YAs) during fermentation provides critical information for evaluating its quality and nutritional attributes. We investigated the effects of homotypic (HO) and heterotypic (HE) lactic acid bacteria on the nutritional and mineral bioavailabilities of soybean YA (SYA) during fermentation. The acidic amino acid (Glu, Asp) and organic acid contents in HO-fermented YA were increased from 2.93, 1.71, and 7.43 mg/100 g to 3.23, 1.82, and 73.47 mg/100 g, respectively. Moreover, both HO and HE lactic acid bacteria fermentation enhanced mineral absorptivity. They altered the molecular speciation of minerals from a large molecular type (2,866 Da) to a small molecular type (1,500 Da), which was manifested in a time-dependent manner. Furthermore, YA substantially increased the bone mass in a zebrafish osteoporosis model, further highlighting the potential of lactic acid bacterial fermentation for mineral bioavailability. This study provides a foundation for understanding the effects of fermentation conditions on the composition and bioavailability of minerals in YA and can assist in its production.

Pteryxin suppresses osteoclastogenesis and prevents bone loss via inhibiting the MAPK/Ca2+ signaling pathways mediated by ROS

Osteoporosis, as a severe public health problem worldwide, causes systemic damage to bone mass, strength, and microstructure with an increased propensity for fragility fractures. Given the inherent adverse effects associated with long-term use of current prescription medications for osteoporosis treatment, identifying natural alternatives to existing treatment methods is imperative. Pteryxin (PTX), a natural coumarin, is isolated from the Peucedanum species belonging to the family Apiaceae. PTX has been reported to have antioxidant, anti-inflammatory and anti-obesity properties. However, its effect on osteoporosis has not been clarified. Our study confirmed that PTX could attenuate the formation of osteoclasts and bone resorption on a dose-dependent basis in vitro. Consistently, in vivo ovariectomy (OVX)-induced osteoporosis models simulating the physiological characteristics of postmenopausal women showed that PTX could partially reverse the bone loss caused by OVX. Further study of its mechanism revealed that PTX might block the MAPK and Ca2+-calcineurin-NFATc1 signaling pathways by decreasing the reactive oxygen species (ROS) level in osteoclasts to dampen the expression of critical transcriptional NFATc1 and downstream osteoclast-specific genes. Overall, PTX may present a new or alternative treatment option for osteoporosis.

Therapeutic effects of isoquercetin on ovariectomy-induced osteoporosis in mice

Bone marrow mesenchymal stem cells (BMSCs) are non-hematopoietic multipotent stem cells capable of differentiating into mature cells. Isoquercetin, an extract from natural sources, has shown promise as a potential treatment for osteoporosis. To investigate the therapeutic effects of isoquercetin on osteoporosis, bone marrow mesenchymal stem cells (BMSCs) were cultured in vitro, and osteogenesis or adipogenesis was induced in the presence of isoquercetin for 14 days. We evaluated cell viability, osteogenic and adipogenic differentiation, as well as mRNA expression levels of Runx2, Alpl, and OCN in osteoblasts, and mRNA expression levels of Pparγ, Fabp4, and Cebpα in adipocytes. The results showed that isoquercetin dose-dependently increased cell viability and promoted osteogenic differentiation, as evidenced by Alizarin Red and alkaline phosphatase staining and mRNA expression levels of Runx2, Alpl, and OCN in osteoblasts (P < 0.05). In contrast, isoquercetin inhibited adipogenic differentiation and decreased the mRNA expression levels of Pparγ, Fabp4, and Cebpα in adipocytes (P < 0.05). In vivo, isoquercetin treatment increased bone quantity and density in an osteoporosis model mice group, as determined by μCT scanning and immunohistochemistry (P < 0.05). These findings suggest that isoquercetin may have therapeutic potential for osteoporosis by promoting the proliferation and differentiation of BMSCs towards osteoblasts while inhibiting adipogenic differentiation.Graphical

Super enhancers targeting ZBTB16 in osteogenesis protect against osteoporosis

As the major cell precursors in osteogenesis, mesenchymal stem cells (MSCs) are indispensable for bone homeostasis and development. However, the primary mechanisms regulating osteogenic differentiation are controversial. Composed of multiple constituent enhancers, super enhancers (SEs) are powerful cis-regulatory elements that identify genes that ensure sequential differentiation. The present study demonstrated that SEs were indispensable for MSC osteogenesis and involved in osteoporosis development. Through integrated analysis, we identified the most common SE-targeted and osteoporosis-related osteogenic gene, ZBTB16. ZBTB16, positively regulated by SEs, promoted MSC osteogenesis but was expressed at lower levels in osteoporosis. Mechanistically, SEs recruited bromodomain containing 4 (BRD4) at the site of ZBTB16, which then bound to RNA polymerase II-associated protein 2 (RPAP2) that transported RNA polymerase II (POL II) into the nucleus. The subsequent synergistic regulation of POL II carboxyterminal domain (CTD) phosphorylation by BRD4 and RPAP2 initiated ZBTB16 transcriptional elongation, which facilitated MSC osteogenesis via the key osteogenic transcription factor SP7. Bone-targeting ZBTB16 overexpression had a therapeutic effect on the decreased bone density and remodeling capacity of Brd4fl/flPrx1-cre mice and osteoporosis (OP) models. Therefore, our study shows that SEs orchestrate the osteogenesis of MSCs by targeting ZBTB16 expression, which provides an attractive focus and therapeutic target for osteoporosis.Without SEs located on osteogenic genes, BRD4 is not able to bind to osteogenic identity genes due to its closed structure before osteogenesis. During osteogenesis, histones on osteogenic identity genes are acetylated, and OB-gain SEs appear, enabling the binding of BRD4 to the osteogenic identity gene ZBTB16. RPAP2 transports RNA Pol II from the cytoplasm to the nucleus and guides Pol II to target ZBTB16 via recognition of the navigator BRD4 on SEs. After the binding of the RPAP2-Pol II complex to BRD4 on SEs, RPAP2 dephosphorylates Ser5 at the Pol II CTD to terminate the transcriptional pause, and BRD4 phosphorylates Ser2 at the Pol II CTD to initiate transcriptional elongation, which synergistically drives efficient transcription of ZBTB16, ensuring proper osteogenesis. Dysregulation of SE-mediated ZBTB16 expression leads to osteoporosis, and bone-targeting ZBTB16 overexpression is efficient in accelerating bone repair and treating osteoporosis.

Identification of key immune genes of osteoporosis based on bioinformatics and machine learning.

Immunity is involved in a variety of bone metabolic processes, especially osteoporosis. The aim of this study is to explore new bone immune-related markers by bioinformatics method and evaluate their ability to predict osteoporosis. The mRNA expression profiles were obtained from GSE7158 in Gene expression Omnibus (GEO), and immune-related genes were obtained from ImmPort database (https://www.immport.org/shared/). immune genes related to bone mineral density(BMD) were screened out for differential analysis. protein-protein interaction (PPIs) networks were used to analyze the interrelationships between different immune-related genes (DIRGs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of DIRGs function were performed. A least absolute shrinkage and selection operation (LASSO) regression model and multiple Support Vector Machine-Recursive Feature Elimination (mSVM-RFE) model were constructed to identify the candidate genes for osteoporosis prediction The receiver operator characteristic (ROC) curves were used to validate the performances of predictive models and candidate genes in GEO database (GSE7158,GSE13850).Through the RT - qPCR verify the key genes differentially expressed in peripheral blood mononuclear cells Finally, we constructed a nomogram model for predicting osteoporosis based on five immune-related genes. CIBERSORT algorithm was used to calculate the relative proportion of 22 immune cells. A total of 1158 DEGs and 66 DIRGs were identified between high-BMD and low-BMD women. These DIRGs were mainly enriched in cytokine-mediated signaling pathway, positive regulation of response to external stimulus and the cellular components of genes are mostly localized to external side of plasma membrane. And the KEGG enrichment analysis were mainly involved in Cytokine-cytokine receptor interaction, PI3K-Akt signaling pathway, Neuroactive ligand-receptor interaction,Natural killer cell mediated cytotoxicity. Then five key genes (CCR5, IAPP, IFNA4, IGHV3-73 and PTGER1) were identified and used as features to construct a predictive prognostic model for osteoporosis using the GSE7158 dataset. Immunity plays an important role in the development of osteoporosis.CCR5, IAPP, IFNA4, IGHV3-73 and PTGER1were play an important role in the occurrences and diagnosis of OP.