Aims. Currently, the effect of drug treatment for osteoporosis is relatively poor, and the side effects are numerous and serious. Melatonin is a potential drug to improve bone mass in postmenopausal women. Unfortunately, the mechanism by which melatonin improves bone metabolism remains unclear. The aim of this study was to further investigate the potential mechanism of melatonin in the treatment of osteoporosis. Methods. The effects of melatonin on mitochondrial apoptosis protein, bmal1 gene, and related pathway proteins of RAW264.7 (mouse mononuclear macrophage leukaemia cells) were analyzed by western blot. Cell Counting Kit-8 was used to evaluate the effect of melatonin on cell viability. Flow cytometry was used to evaluate the effect of melatonin on the apoptosis of RAW264.7 cells and mitochondrial membrane potential. A reactive oxygen species (ROS) detection kit was used to evaluate the level of ROS in osteoclast precursors. We used bmal1-small interfering RNAs (siRNAs) to downregulate the Bmal1 gene. We established a postmenopausal mouse model and verified the effect of melatonin on the bone mass of
Aims. We aimed to develop a gene signature that predicts the occurrence of
Aims. This study explored the shared genetic traits and molecular interactions between
Insufficient protein ingestion may affect muscle and bone mass, increasing the risk of osteoporotic fractures in the elderly, and especially in postmenopausal women. We evaluated how a low-protein diet affects bone parameters under gonadal hormone deficiency and the improvement led by hormone replacement therapy (HRT) with 17β-oestradiol. Female Wistar rats were divided into control (C), ovariectomized (OVX), and 17β-oestradiol-treated ovariectomized (OVX-HRT) groups, which were fed a control or an isocaloric low-protein diet (LP; 6.6% protein; seven animals per group). Morphometric, serum, and body composition parameters were assessed, as well as bone parameters, mechanical resistance, and mineralogy.Objectives
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This study examined whether systemic administration of melatonin would have different effects on osseointegration in ovariectomized (OVX) rats, depending on whether this was administered during the day or night. In this study, a titanium rod was implanted in the medullary cavity of one femoral metaphysis in OVX rats, and then the rats were randomly divided into four groups: Sham group (Sham, n = 10), OVX rat group (OVX, n = 10), melatonin day treatment group (OVX + MD, n = 10), and melatonin night treatment group (OVX + MN, n = 10). The OVX + MD and OVX + MN rats were treated with 30 mg/kg/day melatonin at 9 am and 9 pm, respectively, for 12 weeks. At the end of the research, the rats were killed to obtain bilateral femora and blood samples for evaluation.Aims
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Purpose of the study: Oestrogen depletion leads to osteoclastic hyperactivity and subsequent
Transcription factor nuclear factor kappa B (NF-κB) plays a major role in the pathogenesis of chronic inflammatory diseases in all organ systems. Despite its importance, NF-κB targeted drug therapy to mitigate chronic inflammation has had limited success in preclinical studies. We hypothesized that sex differences affect the response to NF-κB treatment during chronic inflammation in bone. This study investigated the therapeutic effects of NF-κB decoy oligodeoxynucleotides (ODN) during chronic inflammation in male and female mice. We used a murine model of chronic inflammation induced by continuous intramedullary delivery of lipopolysaccharide-contaminated polyethylene particles (cPE) using an osmotic pump. Specimens were evaluated using micro-CT and histomorphometric analyses. Sex-specific osteogenic and osteoclastic differentiation potentials were also investigated in vitro, including alkaline phosphatase, Alizarin Red, tartrate-resistant acid phosphatase staining, and gene expression using reverse transcription polymerase chain reaction (RT-PCR).Aims
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Aims: Compelling evidences suggest that increased production of osteoclastogenic cytokines by activated T cells plays a relevant role in the bone loss induced by estrogen (E) deficiency in the mouse. However, little information is available on the role of T cells in post-menopausal bone loss in humans. Methods: To investigate this issue we have assessed the production of cytokines involved in osteoclasts (OCs) formation (RANKL, TNFα and OPG), in vitro Ocs formation in pre and postmenopausal women, the latter with or without osteoporosis. We also evaluate OC precursors in peripheral blood and the ability of peripheral blood mononuclear cells to produce TNFα in both basal and stimulated condition by flow cytometry in these subjects. Results: Our data demonstrate that E enhances the production of the pro-osteoclastogenetic cytokines TNF alpha and RANKL and increases the number of circulating OCs precursors. Furthermore we show that T cells and monocytes from women with osteoporosis exhibit a higher production of TNF α then those from the other two groups. Conclusions: Our findings suggest that E deficiency stimulates OCs formation both by increasing the production of TNF and RANKL and increasing the number of OCs precursors. Women with
Osteoporosis (OP) is a metabolic bone disease, characterized by a decrease in bone mineral density (BMD). However, the research of regulatory variants has been limited for BMD. In this study, we aimed to explore novel regulatory genetic variants associated with BMD. We conducted an integrative analysis of BMD genome-wide association study (GWAS) and regulatory single nucleotide polymorphism (rSNP) annotation information. Firstly, the discovery GWAS dataset and replication GWAS dataset were integrated with rSNP annotation database to obtain BMD associated SNP regulatory elements and SNP regulatory element-target gene (E-G) pairs, respectively. Then, the common genes were further subjected to HumanNet v2 to explore the biological effects.Aims
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Insufficient treatment response in rheumatoid arthritis (RA) patients requires novel treatment strategies to halt disease progression. The potential benefit of combination of cytokine-inhibitors in RA is still unclear and needs further investigation. To explore the impact of combined deficiency of two major cytokines, namely interleukin (IL)-1 and IL-6, in this study double deficient mice for IL-1αβ and IL-6 were investigated in different tumour necrosis factor (TNF)-driven inflammatory bone disorders, namely peripheral arthritis and sacroiliitis, as well as systemic bone loss. Disease course, histopathological features of arthritis, and micro-CT (µCT) bone analysis of local and systemic bone loss were assessed in 15-week-old Aims
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The association of auraptene (AUR), a 7-geranyloxycoumarin, on osteoporosis and its potential pathway was predicted by network pharmacology and confirmed in experimental osteoporotic mice. The network of AUR was constructed and a potential pathway predicted by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) terms enrichment. Female ovariectomized (OVX) Institute of Cancer Research mice were intraperitoneally injected with 0.01, 0.1, and 1 mM AUR for four weeks. The bone mineral density (BMD) level was measured by dual-energy X-ray absorptiometry. The bone microstructure was determined by histomorphological changes in the femora. In addition, biochemical analysis of the serum and assessment of the messenger RNA (mRNA) levels of osteoclastic markers were performed.Aims
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The role of N,N-dimethylformamide (DMF) in diabetes-induced osteoporosis (DM-OS) progression remains unclear. Here, we aimed to explore the effect of DMF on DM-OS development. Diabetic models of mice, RAW 264.7 cells, and bone marrow macrophages (BMMs) were established by streptozotocin stimulation, high glucose treatment, and receptor activator of nuclear factor-κB ligand (RANKL) treatment, respectively. The effects of DMF on DM-OS development in these models were examined by micro-CT analysis, haematoxylin and eosin (H&E) staining, osteoclast differentiation of RAW 264.7 cells and BMMs, H&E and tartrate-resistant acid phosphatase (TRAP) staining, enzyme-linked immunosorbent assay (ELISA) of TRAP5b and c-terminal telopeptides of type 1 (CTX1) analyses, reactive oxygen species (ROS) analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), Cell Counting Kit-8 (CCK-8) assay, and Western blot.Aims
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Introduction: The evidence of genetic background as an important causative factor in disc degeneration and osteoporosis is increasing. Defects in the COL2A1 gene coding for type II collagen are known to lead to disturbed chondrogenesis and ossification. Retardation of growth, abnormal shape of vertebral bodies and intervertebral discs and occult spina bifida have been described in young mice with the defect. How the gene defect is manifested later in life has not been described. Purpose of the study: The purpose of this study was to describe, at the microscopic level, the structure of intervertebral discs of transgenic Del1 mice carrying a deletion mutation in the Col2a1 gene, and the effect of the gene defect on the structural properties of bone. In addition, we wanted to see how the gene defect manifests in disc tissue and skeletal bone later in life and if there were differences between sexes. Materials and methods: The study material consisted of transgenic male (n=27) and female (n=21) mice and their age-matched littermate controls (n=22 and 21, respectively). The transgenic mice were offspring of the transgenic founder mouse Del1 harbouring six copies of a mouse type II collagen transgene with a 150-bp deletion. The mice were divided into two age groups, the younger group being 3 to 13 months and the older 15 to 21 months of age. The two major macromolecules of the intervertebral discs, proteoglycans (PGs) and collagen, were studied. The PG concentration of the intervertebral discs’ nucleus pulposus, annulus fibrosus, and the vertebral bodies and end plates was measured from Safranin-O-stained sections using digital densitometry. Collagen orientation of these structures was evaluated using quantitative polarised light microscopy. Bone mineral density (BMD) was measured with dual energy x ray absorptiometry (DXA), and the breaking force of the femoral bone with three point bending test only for nine 14-month-old females (four control mice and five with gene defect) and fourteen 14-month-old male mice (six control mice and eight with gene defect). Results: In the young mice, there were no changes in the measured parameters in the intervertebral discs due to the gene defect. However, Safranin-O density and thus PG concentration of the vertebral trabecular bone was 47 % lower in the young transgenic female mice than in the controls (p<
0.001). Ageing had a significant effect on the measured parameters. The Safranin-O density in the nucleus pulposus of the old transgenic male mice was 35 % higher than in the age-matched controls (p<
0.05). In the females, however, Safranin-O density in the nucleus pulposus was 53 % (p<
0.01) and in the vertebral bone 68 % (p<
0.01) lower in the transgenic mice than in the controls. The Safranin-O density in the annulus fibrosus of the transgenic female mice was not changed as compared to the controls. The collagen orientation in the nucleus pulposus of old transgenic male mice was 27 % higher than in the age-matched controls (p<
0.05). In the old females there was no difference in the collagen orientation of the nucleus pulposus between the transgenic mice and controls but in the annulus fibrosus the orientation was 41 % (p<
0.01) and in the vertebral bone 70 % (p<
0.05) lower in the transgenic mice than in the controls. There was no difference in the BMD and the breaking force of the femurs of 14-month-old male mice as compared with the age-matched controls. However, in the old transgenic female mice, the femoral BMD was 14 % (p=0.05) and the breaking force 27 % (p=0.09) lower than in the controls. Conclusions: The transgene of the Col2a1 gene caused a decrease in the nucleus pulposus PG concentration and in the annulus fibrosus collagen orientation in the old female mice. These features can compromise the structural and load-bearing properties of the discs and thus predispose to disc degeneration. Interestingly enough, the male mice seemed to benefit from the genetic defect in this respect. In addition, in the old transgenic female mice, the PG concentration and the collagen orientation of the vertebral trabecular bone were decreased which contributed to the loss of BMD and breaking force of bone seen in these mice. The fact, that these differences in the bone were not seen in the male mice suggests that this animal model could possibly be used in studies of
Osteoarthritis (OA) is prevalent among the elderly and incurable. Intra-articular parathyroid hormone (PTH) ameliorated OA in papain-induced and anterior cruciate ligament transection-induced OA models; therefore, we hypothesized that PTH improved OA in a preclinical age-related OA model. Guinea pigs aged between six and seven months of age were randomized into control or treatment groups. Three- or four-month-old guinea pigs served as the young control group. The knees were administered 40 μl intra-articular injections of 10 nM PTH or vehicle once a week for three months. Their endurance as determined from time on the treadmill was evaluated before kill. Their tibial plateaus were analyzed using microcalculated tomography (μCT) and histological studies.Aims
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The effect of the gut microbiota (GM) and its metabolite on bone health is termed the gut-bone axis. Multiple studies have elucidated the mechanisms but findings vary greatly. A systematic review was performed to analyze current animal models and explore the effect of GM on bone. Literature search was performed on PubMed and Embase databases. Information on the types and strains of animals, induction of osteoporosis, intervention strategies, determination of GM, assessment on bone mineral density (BMD) and bone quality, and key findings were extracted.Aims
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Cigarette smoking has a negative impact on the skeletal system, causes a decrease in bone mass in both young and old patients, and is considered a risk factor for the development of osteoporosis. In addition, it disturbs the bone healing process and prolongs the healing time after fractures. The mechanisms by which cigarette smoking impairs fracture healing are not fully understood. There are few studies reporting the effects of cigarette smoking on new blood vessel formation during the early stage of fracture healing. We tested the hypothesis that cigarette smoke inhalation may suppress angiogenesis and delay fracture healing. We established a custom-made chamber with airflow for rats to inhale cigarette smoke continuously, and tested our hypothesis using a femoral osteotomy model, radiograph and microCT imaging, and various biomechanical and biological tests.Aims
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A balanced inflammatory response is important for successful fracture healing. The response of osteoporotic fracture healing is deranged and an altered inflammatory response can be one underlying cause. The objectives of this review were to compare the inflammatory responses between normal and osteoporotic fractures and to examine the potential effects on different healing outcomes. A systematic literature search was conducted with relevant keywords in PubMed, Embase, and Web of Science independently. Original preclinical studies and clinical studies involving the investigation of inflammatory response in fracture healing in ovariectomized (OVX) animals or osteoporotic/elderly patients with available full text and written in English were included. In total, 14 articles were selected. Various inflammatory factors were reported; of those tumour necrosis factor-α (TNF-α) and interleukin (IL)-6 are two commonly studied markers. Preclinical studies showed that OVX animals generally demonstrated higher systemic inflammatory response and poorer healing outcomes compared to normal controls (SHAM). However, it is inconclusive if the local inflammatory response is higher or lower in OVX animals. As for clinical studies, they mainly examine the temporal changes of the inflammatory stage or perform comparison between osteoporotic/fragility fracture patients and normal subjects without fracture. Our review of these studies emphasizes the lack of understanding that inflammation plays in the altered fracture healing response of osteoporotic/elderly patients. Taken together, it is clear that additional studies, preclinical and clinical, are required to dissect the regulatory role of inflammatory response in osteoporotic fracture healing. Cite this article:
This study aimed to assess the effect of age and osteoporosis on the proliferative and differentiating capacity of bone-marrow-derived mesenchymal stem cells (MSCs) in female rats. We also discuss the role of these factors on expression and migration of cells along the C-X-C chemokine receptor type 4 (CXCR-4) / stromal derived factor 1 (SDF-1) axis. Mesenchymal stem cells were harvested from the femora of young, adult, and osteopenic Wistar rats. Cluster of differentiation (CD) marker and CXCR-4 expression was measured using flow cytometry. Cellular proliferation was measured using Alamar Blue, osteogenic differentiation was measured using alkaline phosphatase expression and alizarin red production, and adipogenic differentiation was measured using Oil red O. Cells were incubated in Boyden chambers to quantify their migration towards SDF-1. Data was analyzed using a Student’s Objectives
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Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides with limited coding potential, which have emerged as novel regulators in many biological and pathological processes, including growth, development, and oncogenesis. Accumulating evidence suggests that lncRNAs have a special role in the osteogenic differentiation of various types of cell, including stem cells from different sources such as embryo, bone marrow, adipose tissue and periodontal ligaments, and induced pluripotent stem cells. Involved in complex mechanisms, lncRNAs regulate osteogenic markers and key regulators and pathways in osteogenic differentiation. In this review, we provide insights into the functions and molecular mechanisms of lncRNAs in osteogenesis and highlight their emerging roles and clinical value in regenerative medicine and osteogenesis-related diseases.
Osteoporosis is a metabolic disease resulting in progressive loss of bone mass as measured by bone mineral density (BMD). Physical exercise has a positive effect on increasing or maintaining BMD in postmenopausal women. The contribution of exercise to the regulation of osteogenesis in osteoblasts remains unclear. We therefore investigated the effect of exercise on osteoblasts in ovariectomized mice. We compared the activity of differentially expressed genes of osteoblasts in ovariectomized mice that undertook exercise (OVX+T) with those that did not (OVX), using microarray and bioinformatics.Objectives
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