Microstructure Of Bone Tissue Research Articles

Electroacupuncture ameliorates senile osteoporosis by promoting bone remodeling and regulating autophagy.

Osteoporosis is widely regarded as a typical aged-related disease caused by impaired bone remodeling. This research was designed to explore the protective effects of electroacupuncture (EA) on senile osteoporosis in a rat model and investigate the underlying mechanisms. Three-month-old rats were randomly selected as the youth group, and 24-month-old rats were randomly assigned to the elderly and EA groups. Rats in the EA group received 30 min of EA at bilateral SP10, ST36, K13 and GB34 daily, 5 days a week for 8 weeks. Bone mineral density (BMD), microstructure of the bone tissue, bone turnover biomarkers and expression level of autophagy-related proteins were detected. Compared with the elderly group, EA treatment significantly increased BMD of the femur and ameliorated the microstructure. EA treatment increased trabecular bone volume ratio (= bone volume / total volume [BV/TV]) and trabecular number (Tb.N) and decreased trabecular separation (Tb.Sp) in senile osteoporosis rats. Compared with the elderly group, the serum N-terminal telopeptide of type I collagen (NTX1) level in the EA group was lower, and the serum procollagen type I N-terminal propeptide (PINP) concentration was higher. In addition, the expression of Beclin 1, microtubule-associated protein I light chain 3 (LC3B) and P62 was inhibited in the senile osteoporosis rats after EA treatment. EA can effectively alleviate aging-related bone loss and improve the microstructure of bone tissue in senile osteoporosis rats, and the regulation of autophagy might be one of the important mechanisms.

Reconstructing Cancellous Bone From Down-Sampled Optical-Resolution Photoacoustic Microscopy Images With Deep Learning

ObjectiveBone diseases deteriorate the microstructure of bone tissue. Optical-resolution photoacoustic microscopy (OR-PAM) enables high spatial resolution of imaging bone tissues. However, the spatiotemporal trade-off limits the application of OR-PAM. The purpose of this study was to improve the quality of OR-PAM images without sacrificing temporal resolution. MethodsIn this study, we proposed the Photoacoustic Dense Attention U-Net (PADA U-Net) model, which was used for reconstructing full-scanning images from under-sampled images. Thereby, this approach breaks the trade-off between imaging speed and spatial resolution. ResultsThe proposed method was validated on resolution test targets and bovine cancellous bone samples to demonstrate the capability of PADA U-Net in recovering full-scanning images from under-sampled OR-PAM images. With a down-sampling ratio of [4, 1], compared to bilinear interpolation, the Peak Signal-to-Noise Ratio and Structural Similarity Index Measure values (averaged over the test set of bovine cancellous bone) of the PADA U-Net were improved by 2.325 dB and 0.117, respectively. ConclusionThe results demonstrate that the PADA U-Net model reconstructed the OR-PAM images well with different levels of sparsity. Our proposed method can further facilitate early diagnosis and treatment of bone diseases using OR-PAM.

The role of magnesium in the pathogenesis of osteoporosis.

Magnesium (Mg), a nutritional element which is essential for bone development and mineralization, has a role in the progression of osteoporosis. Osteoporosis is a multifactorial disease characterized by significant deterioration of bone microstructure and bone loss. Mg deficiency can affect bone structure in an indirect way through the two main regulators of calcium homeostasis (parathyroid hormone and vitamin D). In human osteoblasts (OBs), parathyroid hormone regulates the expression of receptor activator of nuclear factor-κ B ligand (RANKL) and osteoprotegerin (OPG) to affect osteoclast (OC) formation. In addition, Mg may also affect the vitamin D3 -mediated bone remodeling activity. vitamin D3 usually coordinates the activation of the OB and OC. The unbalanced activation OC leads to bone resorption. The RANK/RANKL/OPG axis is considered to be a key factor in the molecular mechanism of osteoporosis. Mg participates in the pathogenesis of osteoporosis by affecting the regulation of parathyroid hormone and vitamin D levels to affect the RANK/RANKL/OPG axis. Different factors affecting the axis and enhancing OC function led to bone loss and bone tissue microstructure damage, which leads to the occurrence of osteoporosis. Clinical research has shown that Mg supplementation can alleviate the symptoms of osteoporosis to some extent.

Characterization and preparation of food-derived peptides on improving osteoporosis: A review

Osteoporosis is a systemic bone disease characterized by reduced bone mass and deterioration of the microstructure of bone tissue, leading to an increased risk of fragility fractures and affecting human health worldwide. Food-derived peptides are widely used in functional foods due to their low toxicity, ease of digestion and absorption, and potential to improve osteoporosis. This review summarized and discussed methods of diagnosing osteoporosis, treatment approaches, specific peptides as alternatives to conventional drugs, and the laboratory preparation and identification methods of peptides. It was found that peptides interacting with RGD (arginine-glycine-aspartic acid)-binding active sites in integrin could alleviate osteoporosis, analyzed the interaction sites between these osteogenic peptides and integrin, and further discussed their effects on improving osteoporosis. These may provide new insights for rapid screening of osteogenic peptides, and provide a theoretical basis for their application in bone materials and functional foods.

Neferine alleviates ovariectomy-induced osteoporosis by enhancing osteogenic differentiation of bone marrow mesenchymal stem cells via regulation of the p38MAPK pathway

ABSTRACT Objective Osteoporosis, a skeletal ailment marked by bone metabolism imbalance and disruption of bone microarchitecture, Neferine, a bisbenzylisoquinoline alkaloid with diverse pharmacological activities, has received limited attention in the context of osteoporosis treatment. Methods We employed a bilateral ovariectomy (OVX) rat model to induce osteoporosis and subsequently administered Neferine treatment for four weeks following successful model establishment. Throughout the modeling and treatment phases, we closely monitored rat body weights. We assessed alterations in bone tissue microstructure through micro-CT, HE staining, and safranin O-fast green staining. Levels of bone formation and resorption markers in serum were evaluated using ELISA assay. Western blot analysis was employed to determine the expression levels of p38MAPK, p-p38MAPK, and bone formation-related genes in bone tissue. We isolated and cultured OVX rat BMSCs (OVX-BMSCs) and induced osteogenic differentiation while simultaneously introducing Neferine and the p38MAPK inhibitor SB203580 for intervention. Results Neferine treatment effectively curbed the rapid weight gain in OVX rats, ameliorated bone loss, and decreased serum levels of TRAP, CTX-I, PINP, and BALP. Most notably, Neferine promoted the expression of bone formation-related factors in bone tissue of OVX rats, while concurrently activating the p38MAPK signaling pathway. In in vitro experiments, Neferine facilitated the expression of bone formation-related factors in OVX-BMSCs, increased the osteogenic differentiation potential of OVX-BMSCs, and activated the p38MAPK signaling pathway. Nevertheless, SB203580 partially reversed Neferine’s promotive effect. Conclusion Neferine can boost the osteoblastic differentiation of BMSCs and alleviate OVX-induced osteoporosis in rats by activating the p38MAPK signaling pathway.

Effects of the combination of Epimedii Folium and Ligustri Lucidi Fructus on apoptosis and autophagy in SOP rats and osteoblasts via PI3K/AKT/mTOR pathway

BackgroundThis study aimed to investigate the effects of the combination of Epimedii Folium (EF) and Ligustri Lucidi Fructus (LLF) on regulating apoptosis and autophagy in senile osteoporosis (SOP) rats. MethodsFirstly, we identified the components in the decoction and drug-containing serum of EL (EF&LLF) by Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS). Secondly, SOP rats were treated with EF, LLF, EL and caltrate to evaluate the advantages of EL. Finally, H2O2-, chloroquine-, and MHY1485-induced osteoblasts were treated with different doses of EL to reveal the molecular mechanism of EL. We detected bone microstructure, oxidative stress levels, ALP activity and the expressions of Bax, Bcl-2, caspase3, P53, Beclin-1, p-PI3K, PI3K, p-Akt, Akt, p-mTOR, mTOR, and LC3 in vivo and in vitro. Results36 compounds in EL decoction and 23 in EL-containing serum were identified, including flavonoids, iridoid terpenoids, phenylethanoid glycosides, polyols and triterpenoids. EL could inhibit apoptosis activity and increase ALP activity. In SOP rats and chloroquine-inhibited osteoblasts, EL could improve bone tissue microstructure and osteoblasts functions by upregulating Bcl-2, Beclin1, and LC3-II/LC3-I, while downregulating p53 in all treatment groups. In H2O2-induced osteoblasts, EL could upregulate the protein and mRNA expressions of Bcl-2 while downregulate LC3-II/LC3-I, p53 and Beclin1. Besides, EL was able to down-regulate PI3K/AKT/mTOR pathway which activated in SOP rats and MHY1485-induced osteoblasts. ConclusionsThese findings demonstrate that EL with bone protective effects on SOP rats by regulating autophagy and apoptosis via PI3K/Akt/mTOR signaling pathway, which might be an alternative medicine for the treatment of SOP.

Effects of tetrahedral DNA nanostructures on the treatment of osteoporosis.

Osteoporosis (OP) is a common disease characterized by bone loss and bone tissue microstructure degradation. Drug treatment is a common clinical treatment that aims to increase bone mass and bone density. Tetrahedral DNA nanostructures (TDNs) are three-dimensional tetrahedral frames formed by folding four single-stranded DNA molecules, which have good biological safety and can promote bone regeneration. In this study, a mouse model of OP was established by ovariectomy (OVX) and TDN was injected into the tail vein for 8 weeks. We found that ovariectomized mice could simulate some physiological changes in OP. After treatment with TDNs, some of this destruction in mice was significantly improved, including an increase in the bone volume fraction (BV/TV) and bone trabecular number (Tb. N), decrease in bone separation (Tb. SP), reduction in the damage to the mouse cartilage layer, reduction in osteoclast lacunae in bone trabecula, and reduction in the damage to the bone dense part. We also found that the expression of ALP, β-Catenin, Runx2, Osterix, and bone morphogenetic protein (BMP)2 significantly decreased in OVX mice but increased after TDN treatment. Therefore, this study suggests that TDNs may regulate the Wnt/β-Catenin and BMP signalling pathways to improve the levels of some specific markers of osteogenic differentiation, such as Runx2, ALP, and Osterix, to promote osteogenesis, thus showing a therapeutic effect on OP mice.

In situ co-deposition synthesis for collagen-Astragalus polysaccharide composite with intrafibrillar mineralization as potential biomimetic-bone repair materials.

A hybrid material possessing both componential and structural imitation of bone tissue is the preferable composites for bone defect repair. Inspired by the microarchitecture of native bone, this work synthesized in vitro a functional mineralized collagen fibril (MCF) material by utilizing the method of in situ co-precipitation, which was designed to proceed in the presence of Astragalus polysaccharide (APS), thus achieving APS load within the biomineralized collagen-Astragalus polysaccharide (MCAPS) fibrils. Transmission electron microscope (TEM), selected area electron diffraction (SAED) and scanning electronic microscopy (SEM) identified the details of the intrafibrillar mineralization of the MCAPS fibrils, almost mimicking the secondary level of bone tissue microstructure. A relatively uniform and continuous mineral layer formed on and within all collagen fibrils and the mineral phase was identified as typical weak-crystalline hydroxyapatite (HA) with a Ca/P ratio of about 1.53. The proliferation of bone marrow-derived mesenchymal stem cells (BMSC) and mouse embryo osteoblast precursor cells (MC3T3-E1) obtained a significant promotion by MCAPS. As for the osteogenic properties of MCAPS, a distinct increase in the alkaline phosphatase (ALP) activity and the number of calcium nodules (CN) in BMSC and MC3T3-E1 was detected. The up-regulation of three osteogenic-related genes of RUNX-2, BMP-2 and OCN were confirmed via reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to further verify the osteogenic performance promotion of MCAPS. A period of 14 days of culture demonstrated that MCAPS-L exhibited a preferable efficacy in enhancing ALP activity and CN quantity, as well as in promoting the expression of osteogenic-related genes over MCAPS-M and MCAPS-H, indicating that a lower dose of APS within the material of MCAPS is more appropriate for its osteogenesis promotion properties.

UPLC-Q-TOF-MS-based metabolomics reveals mechanism of Morinda officinalis iridoid glycosides in treating rheumatoid arthritis and bone loss

This study aimed to investigate the therapeutic effects of Morinda officinalis iridoid glycosides(MOIG) on paw edema and bone loss of rheumatoid arthritis(RA) rats, and analyze its potential mechanism based on ultra-high performance liguid chromatography-guadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF-MS) serum metabolomics. RA rats were established by injecting bovin type Ⅱ collagen. The collagen-induced arthritis(CIA) rats were administered drug by gavage for 8 weeks, the arthritic score were used to evaluate the severity of paw edem, serum bone metabolism biochemical parameters were measured by ELISA kits, Masson staining was used to observe the bone microstructure of the femur in CIA rats. UPLC-Q-TOF-MS was used to analyze the alteration of serum metabolite of CIA rats, principal component analysis(PCA) and partial least squares-discriminant analysis(PLS-DA) were used to screen the potential biomarkers, KEGG database analysis were used to construct related metabolic pathways. The results demonstrated that the arthritic score, serum levels of IL-6 and parameters related with bone metabolism including OCN, CTX-Ⅰ, DPD and TRAP were significantly increased, and the ratio of OPG and RANKL was significantly decreased, the microstructure of bone tissue and cartilage were destructed in CIA rats, while MOIG treatments could significantly reduce arthritis score, mitigate the paw edema, reverse the changes of serum biochemical indicators related with bone metabolism, and improve the microstructure of bone tissue and cartilage of CIA rats. The non-targeted metabolomics results showed that 24 altered metabolites were identified in serum of CIA rats; compared with normal group, 13 significantly altered metabolites related to RA were identified in serum of CIA rats, mainly involving alanine, aspartate and glutamate metabolism; compared with CIA model group, MOIG treatment reversed the alteration of 15 differential metabolites, mainly involving into alanine, aspartate and glutamate metabolism, D-glutamine and D-glutamate metabolism, taurine and hypotaurine metabolism, valine, leucine and isoleucine biosynthesis. Therefore, MOIG significantly alleviated paw edema, improved the destruction of microstructure of bone and cartilage in CIA rats maybe through involving into the regulation of amino acid metabolism.

Dual role of sclerostin and other parameters in postmenopausal women with osteoporosis

Background & objective: Osteoporosis is a chronic progressive disease, characterized by decreased bone mass and damage to the microstructure of bone tissue, leading to decreased bone strength and increased risk of fractures. The main serious consequence of osteoporosis is fragility fracture. This case-control study was conducted to know the prevalence of osteoporosis in Iraqi postmenopausal women. Methodology: One hundred female patients visiting Al-Sader Teaching Hospital in Al-Najaf province of Iraq, were included in the study. To determine the percentage of their bone density we used a dual energy x-ray absorptiometry (DEXA). Blood samples were taken after diagnosing the disease. In addition, serum estrogen and vitamin D3 were measured by enzyme linked immune sorbent assay (ELISA), while alkaline phosphatase was measured by spectrophotometer. Data were gathered by direct interviews with the women. The study excluded those who had chronic diseases. Results: This study showed a significant increase (P < 0.05) in the concentration of sclerostin and alkaline phosphatase and non-significant differences in vitamin D3 concentrations between patients and healthy group. Conclusion: Increased serum sclerostin and alkaline phosphatase levels in postmenopausal women with osteoporosis play an important role in the development of primary osteoporosis. Key word: Osteoporosis; Sclerostin; DEXA Citation: Ahmed NH, Jaffat HS, Alrufaie MM. Dual role of sclerostin and other parameters in postmenopausal women with osteoporosis. Anaesth. pain intensive care 2023;27(6):745−749; DOI: 10.35975/apic.v27i6.2349 Received: August 22, 2023; Revised: August 29, 2023; Accepted: September 11, 2023

Research progress on the treatment of knee osteoarthritis combined with osteoporosis by single-herb Chinese medicine and compound.

Knee osteoarthritis (KOA) is a degenerative disease with synovial inflammation, articular surface cartilage degeneration, meniscus degeneration, ligament and muscle changes, subchondral bone changes, and osteophyte formation around the joint as the main pathological changes. Osteoporosis (OP) is a disease characterized by low bone mass and deterioration of the microstructure of bone tissue. KOA and OP are both geriatric diseases, and the incidence of KOA combined with OP is high, but there is a lack of specific drugs, and the major treatments are limited to drug therapy. Most traditional Chinese medicine (TCM) treatments use plant-based natural products, and they help patients obtain good clinical benefits and at the same time provide researchers with ideas to study the mechanism of disease occurrence and the relationship between the two diseases. This article summarizes the research progress of TCM monomers and TCM compounds that are frequently used to treat KOA combined with OP to provide ideas for future clinical treatments and related basic research.

Phase-contrast imaging with synchrotron hard X-ray reveals the effect of icariin on bone tissue morphology and microstructure in rabbits with early glucocorticoid-induced osteonecrosis of the femoral head.

Background: Phase-contrast imaging (PCI) with synchrotron hard X-ray was used to observe the changes in bone tissue morphology and microstructure in rabbit models of early glucocorticoid-induced osteonecrosis of the femoral head (ONFH), and to evaluate the intervention effect of Icariin. Methods: Fifty mature New Zealand rabbits (weighing 2.5-3.0kg) were randomly divided into a control group (n = 10), a glucocorticoid group (n = 20), and an Icariin group (n = 20). The glucocorticoid group and the Icariin group were sequentially injected with lipopolysaccharide (LPS) and methylprednisolone (MPS) to establish a glucocorticoid-induced ONFH animal model. The Icariin group was given Icariin solution when methylprednisolone was injected for the first time, and the control group and glucocorticoid group were given the same amount of normal saline. Animals were sacrificed after 6weeks, and bilateral femoral head specimens were taken for research. The right femoral head was observed by PCI with synchrotron hard X-ray technology, and the left femoral head was verified by Micro-CT scanning and HE staining. Results: Forty-three animals (nine in the control group, sixteen in the glucocorticoid group, and eighteen in the Icariin group) were included in the study. PCI with synchrotron hard X-ray revealed that the trabecular bone in the glucocorticoid group was thinned, broken, and structurally damaged, whereas the trabecular bone in the Icariin group had normal volume, thickness, and a relatively intact structure. Micro-CT scan reconstruction and HE staining were used to verify the reliability of this technique in identifying osteonecrosis. Conclusion: The effects of Icariin were observed in an early glucocorticoid-induced ONFH rabbit model using PCI with synchrotron hard X-ray. Icariin weakens the destructive effect of glucocorticoids on bone tissue structure, improves bone tissue morphology, and stabilizes bone microstructure. This technique may provide a definitive, non-invasive alternative to histological examination for the diagnosis of early ONFH.

Osteoimmunomodulatory Nanoparticles for Bone Regeneration.

Treatment of large bone fractures remains a challenge for orthopedists. Bone regeneration is a complex process that includes skeletal cells such as osteoblasts, osteoclasts, and immune cells to regulate bone formation and resorption. Osteoimmunology, studying this complicated process, has recently been used to develop biomaterials for advanced bone regeneration. Ideally, a biomaterial shall enable a timely switch from early stage inflammatory (to recruit osteogenic progenitor cells) to later-stage anti-inflammatory (to promote differentiation and terminal osteogenic mineralization and model the microstructure of bone tissue) in immune cells, especially the M1-to-M2 phenotype switch in macrophage populations, for bone regeneration. Nanoparticle (NP)-based advanced drug delivery systems can enable the controlled release of therapeutic reagents and the delivery of therapeutics into specific cell types, thereby benefiting bone regeneration through osteoimmunomodulation. In this review, we briefly describe the significance of osteoimmunology in bone regeneration, the advancement of NP-based approaches for bone regeneration, and the application of NPs in macrophage-targeting drug delivery for advanced osteoimmunomodulation.

Positive Effects of Biologics on Osteoporosis in Rheumatoid Arthritis.

Osteoporosis is a systemic skeletal disorder that causes vulnerability of bones to fracture owing to reduction in bone density and deterioration of the bone tissue microstructure. The prevalence of osteoporosis is higher in patients with autoimmune inflammatory rheumatic diseases, including rheumatoid arthritis (RA), than in those of the general population. In this autoimmune inflammatory rheumatic disease, in addition to known risk factors for osteoporosis, various factors such as chronic inflammation, autoantibodies, metabolic disorders, drugs, and decreased physical activity contribute to additional risk. In RA, disease-related inflammation plays an important role in local or systemic bone loss, and active treatment for inflammation can help prevent osteoporosis. In addition to conventional synthetic disease-modifying anti-rheumatic drugs that have been traditionally used for treatment of RA, biologic DMARDs and targeted synthetic DMARDs have been widely used. These agents can be employed more selectively and precisely based on disease pathogenesis. It has been reported that these drugs can inhibit bone loss by not only reducing inflammation in RA, but also by inhibiting bone resorption and promoting bone formation. In this review, the pathogenesis and research results of the increase in osteoporosis in RA are reviewed, and the effects of biological agents on osteoporosis are discussed.

On the fracture behavior of cortical bone microstructure: The effects of morphology and material characteristics of bone structural components

Bone encompasses a complex arrangement of materials at different length scales, which endows it with a range of mechanical, chemical, and biological capabilities. Changes in the microstructure and characteristics of the material, as well as the accumulation of microcracks, affect the bone fracture properties. In this study, two-dimensional finite element models of the microstructure of cortical bone were considered. The eXtended Finite Element Method (XFEM) developed by Abaqus software was used for the analysis of the microcrack propagation in the model as well as for local sensitivity analysis. The stress–strain behavior obtained for the different introduced models was substantially different, confirming the importance of bone tissue microstructure for its failure behavior. Considering the role of interfaces, the results highlighted the effect of cement lines on the crack deflection path and global fracture behavior of the bone microstructure. Furthermore, bone micromorphology and areal fraction of cortical bone tissue components such as osteons, cement lines, and pores affected the bone fracture behavior; specifically, pores altered the crack propagation path since increasing porosity reduced the maximum stress needed to start crack propagation. Therefore, cement line structure, mineralization, and areal fraction are important parameters in bone fracture.The parameter-wise sensitivity analysis demonstrated that areal fraction and strain energy release rate had the greatest and the lowest effect on ultimate strength, respectively. Furthermore, the component-wise sensitivity analysis revealed that for the areal fraction parameter, pores had the greatest effect on ultimate strength, whereas for the other parameters such as elastic modulus and strain energy release rate, cement lines had the most important effect on the ultimate strength. In conclusion, the finding of the current study can help to predict the fracture mechanisms in bone by taking the morphological and material properties of its microstructure into account.

Antiosteoporosis and bone protective effect of nimbolide in steroid-induced osteoporosis rats.

Osteoporosis is a metabolic, hereditary, progressive disease characterized by unusual bone production across the skeleton and a loss the bone tissue microstructure and mass. In this experimental study, we scrutinized the antiosteoporosis effect of nimbolide against glucocorticoid (GCs) induced osteoporosis in rats. Swiss albino female rats were employed for the current experiment study and the rats were divided into different groups. Dexamethasone (0.1 mg/kg/day) was used for induction the osteoporosis and the rats were received the different doses of nimbolide (2.5, 5, and 7.5 mg/kg) for the estimation of bone protective effects. The body weight was estimated (initially and finally). Hormones, bone metabolic markers, bone turnover markers, bone structure, biomechanical, histomorphometric dynamic, biochemical markers, and histomorphometric static parameters were analyzed. The body weight of GCs group rats considerably suppressed and nimbolide treatment remarkably improved the body weight. Nimbolide treated group exhibited the enhancement of bone metabolic, bone structure markers, and histomophometric dynamic markers, which was suppressed during the GCs-induced osteoporosis. GCs-induced osteoporosis rats exhibited the enhancement of procollagen type 1 C-terminal propeptide (P1CP), carboxy-terminal crosslinked telopeptide of type 1 collagen (CTX-1), Dickkopf-1 (DKK1), tartrate-resistant acid phosphatase 5b (TRACP 5b), and suppressed the level of bone alkaline phosphatase (BAP), which was reversed by the nimbolide treatment. Nimbolide treatment remarkably improved the level of estradiol and suppressed the level of parathyroid hormone (PTH), which was altered during the osteoporosis. Nimbolide treatment significantly (p < 0.001) improved the level of calcium, magnesium, and phosphorus in the serum and bone tissue. Nimbolide treatment also altered the level of bone metabolic markers and suppressed the level of inflammatory cytokines. Based on the findings, we may conclude that nimbolide has antiosteoporosis properties via balancing the bone mass and improving vitamin and hormone levels.

RESULTS of MORPHOLOGICAL ANALYSIS of ANIMAL HARD TISSUES IN NORMAL AND SIMULATED OSTEOPOROSIS USING A NON-INVASIVE COMPUTED MICROTOMOGRAPHY TECHNIQUE

Introduction. X-ray microtomography is a non-destructive method of microstructural analysis, which has a high level of detail and allows the possibility of assessing the internal architecture of organs and tissues using 3D-analysis[1]. The specifics of working with such equipment can be divided into in vivo and in vitro, i.e. working with live laboratory animals (mice, rats, rabbits) under anesthesia or studying organs and tissues separated from the animal [2].The aim of the work was to study the microstructure of sheep bone tissues in normal and simulated osteoporosis using computed microtomography.Materials and methods. We performed microCT analysis of different sheep bones in normal and experimental osteoporosis. Bone tissue of the jaw, iliac and femur, and teeth were collected from control and experimental animals. Bone tissue samples were fixed in 10% buffered formalin. X-ray microCT scanner Skyscan 1176 (BrukermicroCT, Belgium) and software Skyscan 1176 control program (10.0.0.0), Nrecon (1.7.4.2), DataViewer (1.5.6.2), CT-analyser (1.18.4.0), CTvox (3.3.0r1403) were used to scan and process materials.Results. MicroCT examination and 3D-imaging confirmed the elimination of trabeculae in the metaphyseal region of the femur in sheep with experimental osteoporosis from the centre to the periphery; in addition, 3D-analysis showed a 15.1% decrease in bone percentage, a 7.8% decrease in bone mineral density, and an increase in Tb. Sp. (trabecular separation), Tb. Pf. (trabecular pattern factor) and SMI (structure model index) by 30.2%, 20.8% and 23.6%, respectively, and a decrease in Tb.N. (trabecular number) index by 18.6%, indicating calcium washout, decreased trabecular connectivity and a transition from a lamellar to a rod-like architecture. Similar changes were found in the 3D-analysis of the jaw bone tissue. Thus, a decrease of 18.9% in mineral density was found, as well as a significant increase of 11.58 and 2.21 in the indices, particularly Tb. Pf. and SMI. 3D-analysis of iliac microtomography also indicates a simulation of osteoporosis, as evidenced by a significant increase in the main indices characterising the development of this pathology.Conclusions. The obtained results not only objectively testify to the development of osteoporosis in the experimental animals, but also indicate signs of the adaptation-compensatory reactions of the body, characterized by appearance of large single trabeculae in the metaphysis of the femur as well as by not expressed reduction of bone mineral density and bone tissue area.

Bioinformatics analysis identification of AKT3 and RAC1 as key genes in postmenopausal osteoporosis.

Postmenopausal osteoporosis (PMO) is an aging-associated disease that manifests as degradation of bone tissue microstructure leading to decreased bone mass and increased bone fragility. Differentiation of peripheral blood mononuclear cells into osteoclasts is an important process in the development of PMO and identification of key genes that drive differentiation is essential to reveal the mechanism of PMO. The present study combined bioinformatics analysis of a Gene Expression Omnibus dataset of PMO and drug (bisphosphonate) target prediction using the STITCH database to identify hub genes in patients with PMO. Next, the expression of candidate hub genes was assessed in osteoclasts differentiated from THP-1 cells and small interfering RNA assays were performed to assess the function of selected hub genes. The present study identified 10 hub genes including WNT1, AKT3, disheveled segment polarity protein 1, cyclin D1, H2B clustered histone 17, JUN, EGFR, RAC1, actinin α1 (ACTN1) and ACTN2. Among these, AKT3 and RAC1 were highly upregulated during osteoclast differentiation, and knockdown of AKT3 and RAC1 using small interfering RNA enhanced the inhibitory effect of bisphosphonates on osteoclast differentiation and apoptosis of monocytes as assessed by tartrate-resistant acid phosphatase staining and flow cytometry examining Annexin V-FITC/PI staining, respectively. In conclusion, AKT3 and RAC1 were key for development of PMO and inhibiting AKT3 and RAC1 may improve the therapeutic efficacy of bisphosphonates.

The roles of circRNA-miRNA-mRNA networks in the development and treatment of osteoporosis.

Osteoporosis is a systemic metabolic disease, mainly characterized by reduced bone mineral density and destruction of bone tissue microstructure. However, the molecular mechanisms of osteoporosis need further investigation and exploration. Increasing studies have reported that circular RNAs (circRNAs), a novel type of RNA molecule, play crucial roles in various physiological and pathological processes and bone-related diseases. Based on an in-depth understanding of their roles in bone development, we summarized the multiple regulatory roles and underlying mechanisms of circRNA–miRNA–mRNA networks in the treatment of osteoporosis, associated with bone marrow mesenchymal stem cells (BMSCs), osteoblasts, and osteoclasts. Deeper insights into the vital roles of circRNA–miRNA–mRNA networks can provide new directions and insights for developing novel diagnostic biomarkers and therapeutic targets in the treatment of osteoporosis.

COMPARATIVE MORPHOLOGY OF TUBULAR BONES OF BLAGOVARSKY CROSS DUCKS IN THE POSTNATAL PERIOD OF ONTOGENESIS

The microstructure of limb skeletal bones is closely related to ontogenetic age, localised skeletal growth dynamics, biomechanical modes of bone load, and possible taxonomic differences. This is important for the investigation of the problematic issues of ontogenetic changes in the compact bone tissue of domestic ducks. The purpose of the study was to compare the microstructure of the mid-diaphysis of the humerus and femur bones of Blagovarsky cross ducks, depending on age and gender. The material for research was the tubular bones of the thoracic (humerus) (n = 72) and pelvic (femur) (n = 72) limbs of Blagovarsky cross ducks aged 1 day, 10, 20, 30, 90, 196, 268, 341 and 483 days of postnatal ontogenesis of both sexual groups (females and males of 36 ducks each), a total of 72 ducks. The timing of the selection of ducks coincided with the technological cycle of their cultivation. Histological sections with a thickness of 5-10 microns were obtained, which were dyed with hematoxylin Karatsi and eosin, and according to Van Gieson for connective tissue differentiation. Morphometry determined the quantitative indicators of compact bone tissue in the middle of the diaphysis of tubular bones: the diameter of the diaphysis, the thickness of the periosteum, compact bone tissue, the diameter of osteons and central channels of osteons (Havers channels). It was discovered that the growth of the humerus and femur bones in length and thickness is completed on the 196th day of the postnatal period of ontogenesis in both female and male ducks. It was established that medullary (cerebral) bone tissue (1.01 ± 0.10 mm) appears from the femoral endostus of females, which is formed on the 196th day of the postnatal period of ontogenesis (the beginning of sexual maturity of females) and is further observed in intensive periods of their egg production on 268 and 341 days (2.43 ± 0.56 and 2.55 ± 0.62 mm, respectively), and disappears on the 483rd day (0.20 ± 0.03 mm) when the duck is not laying eggs. This study for the first time determined the age dynamics of morphometric parameters of microstructures of compact bone tissue of the humerus and femur and established their sex differences in ducks of the Blagovarsky cross. The results of comparative morphology studies are necessary for determining the age, sex, and species of birds based on the microstructure of compact bone tissue in the middle of the diaphysis of tubular bones, and for the ability to differentiate changes in the occurrence of limb pathologies in poultry