Femoral Bone Tissue Research Articles

Ameliorative effects of Osteo-F, a newly developed herbal formula, on osteoporosis via activation of bone formation

Ethnopharmacological relevanceThe fruit of Schizandra chinensis and Lycium chinense, and the root of Eucommia ulmoides, components of Osteo-F, has traditionally been used for treating bone diseases in Korean Medicine. Aim of the studyThe exact role and underlying mechanism of Osteo-F herbal formula on bone formation in osteoporosis was investigated in the present study. Materials and methodsOVX mice were treated with 0.9, 9 and 90 mg/kg of Osteo-F for 4 weeks. Bone tissues including fourth to sixth lumbar vertebrae (LV) and femur were collected to analyze the bone mineral density (BMD). In addition, serum biomarkers were estimated by enzyme-linked immunosorbent assay. The expressions of collagen, BMP-2 and osteopontin were determined in tibia to clarify the bone anabolic effects of Osteo-F in osteoporosis. ResultsThe levels of BMD in both of fourth to sixth LV and femur were significantly increased by Osteo-F treatment in OVX mice. Bone mineral content (BMC) was also elevated in Osteo-F-treated LV and femoral bone tissues. In addition, serum osteocalcin was markedly increased by Osteo-F in osteoporotic mice. Serum ALP and bALP levels were neutralized in Osteo-F 90 mg/kg-administered mice. Furthermore, Osteo-F treatment dramatically increased the mRNA expressions of collagen type I, BMP-2 and OPN in tibial bone specimens. ConclusionsOsteo-F ameliorated bone loss by increasing bone forming molecules including BMP-2 and OPN in osteoporosis. Osteo-F, a newly developed herbal formula, may be an alternative material for the management of osteoporosis with bone anabolic effects.

Three-Dimensional, MultiScale, and Interconnected Trabecular Bone Mimic Porous Tantalum Scaffold for Bone Tissue Engineering

To investigate the biocompatibility and bone ingrowth properties of a novel trabecular bone mimic porous tantalum scaffold which holds potential for bone tissue engineering, a novel three-dimensional, multiscale interconnected porous tantalum scaffold was designed and manufactured. The morphology of the novel scaffold was observed with the use of scanning electron microscopy (SEM) and industrial computerized tomography. Mesenchymal stem cells (MSCs) were cultured with novel porous tantalum powder, SEM was carried out for the observation of cell morphology and adhesion, and cytotoxicity was evaluated by the MTT assay. Canine femoral shaft bone defect models were established, and novel porous tantalum rods were used to repair the bone defect. Repair effects and bone integration were evaluated by hard tissue slice examination and push-out tests at the indicated time. We found that the novel porous tantalum scaffold is a trabecular bone mimic, having the characteristics of being three-dimensional, multiscaled, and interconnected. The MSCs adhered to the surface of tantalum and proliferated with time, the tantalum extract did not have a cytotoxic effect on MSCs. In the bone defect model, porous tantalum rods integrated tightly with the host bone, and new bone formation was found on the scaffold-host bone interface both 3 and 6 months after the implantation. Favorable bone ingrowth was observed in the center of the tantalum rod. The push-out test showed that the strength needed to push out the tantalum rod is comparable for both 3 and 6 months when compared with the normal femoral shaft bone tissue. These findings suggested that the novel trabecular bone mimic porous tantalum scaffold is biocompatible and osteoinductive, which holds potential for bone tissue engineering application.

Varying development of femoral and tibial subchondral bone tissue and their interaction with articular cartilage during progressing osteoarthritis.

Differences between tibial and femoral joint surfaces and knee compartments concerning coupled bone and cartilage turnover or bone-cartilage cross talk have not been previously examined, although the mechanical and biological interaction of the mineralized subchondral tissues with articular cartilage is of great importance for advancing osteoarthritis. Therefore, with the help of immunohistochemistry and real-time polymerase chain reaction (RT-PCR), human knee joint cartilage tissue was investigated for expression of key molecules of the extracellular matrix and cartilage composition (collagen type I and II, aggrecan) plus proteoglycan content (colorimetric analysis). Furthermore, we correlated the results with 3D microcomputed tomography of the underlying subchondral bone (high-resolution micro-CT system). Measurements were performed in dependence of the anatomical site (femoral vs. tibial, medial and lateral each) to identify regional differences during the osteoarthritic process. From an enduring series of 108 patients undergoing implantation of TKA, 34 osteochondral samples with lesions macroscopically classified as ICRS grade 1b (group A) and 34 samples with ICRS grade 3a/3b lesions (group B) were compared with 21 healthy controls. Concerning 3D analysis, the medial femoral condyle and tibia showed the most significant increase in bone volume fraction and a decrease in the trabecular number in group B frequently accompanied by subchondral bone resorption pits and enchondral ossification. Under physiological conditions, tibia plateaus show lower bone volume fraction than the corresponding femoral site and this difference enlarges with advancing OA. Partially even contradictory behavior was observed such as trabecular separation at the lateral tibial and medial plateau in osteochondral OA samples of the same patients. Collagen type II expression levels show faster and varying changes than type I during the OA process, leading to a lower positive or negative correlation with bone microstructural analysis, especially on the tibia plateau. Structural bone and cartilage parameter changes showed varying developments and correlations among each other in the different compartments of the knee. As a clinical conclusion, therapies to postpone or prevent cartilage degeneration by influencing the loss of mineralized bone could be site dependent.

Exercise Mitigates Bone Loss via ROS‐NLRP3 Inflammasome Axis In High Fat Diet Fed Mice

Emerging evidence suggests that western diet‐induced obesity is associated with chronic low‐grade inflammation. Chronic inflammation is also linked with increased bone loss and osteopenia phenotype. However, the mechanistic basis of obesity‐associated bone loss via induction of inflammasome is not yet well understood. The recent study also found that irisin is expressed by various tissue including skeletal muscle during exercise. It is also currently unknown whether irisin is secreted by bone tissue upon exercise and possible involvement in the regulation of NLRP3 inflammasome activation during obesity in mice. To test the hypothesis, we employed 8‐weeks age‐matched male/female C57BJ/L6 wild‐type (WT) mice were grouped as fellows according to their diet and exercise (Ex) category: standard nonfat diet NFD (6%); (ii) NFD+Ex; (iii) HFD (42%); (iv) HFD+Ex. A nonfat diet (6%) and a high‐fat diet (40%) were given for three months. The selected mice were exercised for this 12‐week duration on a treadmill, with controlled speeds of 7 meters/min for the first week, 9 meters/min for the second week and 11 meters/min the following weeks for a total of 330 meters every day. After every 110 meters reached, the mice were given rest of 10 minutes. We tested protein/mRNA expression of oxidative stress, inflammasome metabolic indicators Glucose Transporters 1 and 4 (GLUT‐1, GLUT‐4), irisin, IL‐6, and IL‐1β in primarily isolated bone marrow mesenchymal cells (BMMSCs), plasma and bone from all the groups by Western Blot, real‐time PCR, and Immunohistochemistry. The data demonstrated that high levels of irisin protein expression were induced in both plasma and murine femoral bone tissues of HFD+EX mice. The mechanistic study shows that cellular oxidative damage and NLR3 signaling was indeed down‐regulated and resulted in decreased secretion of IL‐6 and IL‐1β in bone marrow mesenchymal cells (BMMSCs) and plasma of HFD+EX mice. Interestingly, HFD+EX mice showed higher trabecular, cortical bone formation and bone strength in vivo in compared to HFD mice. Lentiviral FNDC5/recombinant irisin administration suppresses HFD induced ROS‐NLR3 inflammation and restores bone mass, whereas blockade of FNDC5/irisin by siRNA delivery prevents the physical exercise mediated bone formation in HFD mice. Further osteoblast‐specific FNDC5 (or Irisin) deficiency in mice completely blocks EX‐induced trabecular bone formation. In conclusion, our findings demonstrate that exercise‐induced irisin mitigates the bone loss in part via inhibiting ROS‐NLR3 signaling in HFD mice, and possibly provide a mechanism for therapeutic effect in metabolic osteoporosis.Support or Funding InformationAcknowledgmentThis work is financially supported by the National Institute of Health Grant AR‐067667‐NT is greatly acknowledged.

Experimental justification of the method of mesenchymal stem cell autotransplantation for regeneration of the femoral head bone tissue

The results of experimental justification of a new method for restoring the femoral head bone tissue with the use of mesenchymal stem cells (MSCs) are presented. Surgical interventions were performed on 5 dogs, including the bone marrow exfusion, the obtaining of MSCs and their subsequent osteogenic differentiation, the selection of a carrier for MSCs, the creation of femoral head defects, and the implantation of a cellular product into a bone defect. Experimental animals were observed and cared after operations, and removed from the experiment, as well as the biological material was taken. The histological results of the femoral head micropreparations of dogs confirm the formation of the mature bone tissue of compact structure with osteoblasts at the site of MSCs injection. In the control group of the experimental samples (without MSCs), the The obtained experimental material will allow us to develop a method for autologous transplantation of MSCs for regenerative restoration of bone tissue damage in the adult’s femoral head osteonecrosis, which will find use in the practical healthcare system.

Local Vancomycin Concentrations after Intra-articular Injection into the Knee Joint: An Experimental Porcine Study.

Intra-articular injection of vancomycin may be an important antimicrobial prophylactic supplement to systemic administration in the prevention of prosthetic joint infections. In eight female pigs, 500 mg of diluted vancomycin was given by intra-articular injection into the knee joint. Microdialysis was used for dense sampling of vancomycin concentrations over 12 hours in the synovial fluid of the knee joint, and in the adjacent femoral and tibial cancellous bone and subcutaneous tissue. Venous blood samples were obtained as reference. The mean (standard deviation [SD]) peak drug concentration of vancomycin in the synovial fluid of the knee joint was 5,277 (5,668) μg/mL. Only one pig failed to reach a peak drug concentration above 1,000 μg/mL. The concentration remained high throughout the sampling interval with a mean (SD) concentration of 337 (259) μg/mL after 690 minutes. For all extraarticular compartments, the pharmacokinetic parameters (area under the concentration time-curve, peak drug concentration, and time to peak drug concentration) were comparable. The highest extraarticular mean (SD) peak drug concentration of 4.4 (2.3) μg/mL was found in subcutaneous tissue. An intra-articular injection of 500 mg diluted vancomycin was found to provide significant prophylactic mean concentrations for at least 12 hours in the synovial fluid of the knee joint. Correspondingly, the adjacent tissue and plasma concentrations were low but remained stable, signifying low risk of systemic toxic side effects and a slow release or uptake from the synovium to the systemic circulation.

Effect of Growth Hormone (GH) and Resistance Training on the Collagen Properties of Femoral Bone Tissue

Effect of Growth Hormone (GH) and Resistance Training on the Collagen Properties of Femoral Bone Tissue

Differentially expressed microRNA and target gene analysis in patients with postmenopausal osteoporosis

Objective To analyze the differentially expressed microRNA (miRNA) and their target genes in peripheral blood and bone tissue of postmenopausal osteoporosis (PMOP), and provide basis for the study of pathogenesis as well as biomarkers identification of PMOP. Methods Two miRNA datasets of PMOP from the public platform NCBI-GEO DataSets were obtained, including GSE64433 (the miRNA expression profile of peripheral blood samples, including 23 PMOP patients and 25 controls) and GSE74209 (the miRNA expression profile of the femoral neck bone tissue sample, including six PMOP patients and six controls). R/Bioconductor was performed for data analysis and differentially expressed miRNA screening, and miRNAs with fold change>2 & P<0.05 between osteoporosis and controls were selected as differentially expressed miRNA. The miRNA target gene prediction was performed by combining TargetScan, miRDB and miRTarBase databases. The miRNA-target gene regulatory network was constructed and analyzed by Cytoscape. Results There were 224 differentially expressed miRNAs (75 up-regulated miRNAs and 149 down-regulated miRNAs) in the peripheral blood samples of PMOP group (GSE64433 dataset) and 132 differentially expressed miRNAs (58 up-regulated miRNAs and 74 down-regulated miRNAs) in the femoral neck bone tissue of PMOP group (GSE74209 dataset). We combined the results from the two datasets and obtained 8 miRNAs down-regulated in both datasets, and the 8 miRNAs regulated a total of 327 target genes, and 10 of these target genes were co-regulated by two miRNAs. Conclusions The core miRNAs and the target genes regulated by multiple miRNAs in the regulatory network may play important roles in the pathogenesis of PMOP and have potential application values as molecular biomarkers of disease. These findings are meaningful for the studies of PMOP pathogenesis, biomarkers screening and prevention of osteoporotic fractures. Key words: Osteoporosis, postmenopausal; MicroRNAs; Regulatory network

Effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue: analysis by Raman spectroscopy, dual-energy X-ray absorptiometry, and mechanical resistance.

The aim of the present study was to verify the effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue by Raman spectroscopy (Raman), dual-energy X-ray absorptiometry (DXA), and mechanical resistance (F-max) analysis. A total of 40 male Wistar animals, 60days old, were used. The animals were distributed into four groups: control (C), control with GH (GHC), muscular strength training (T), and muscular strength training with GH (GHT). Blood samples were collected for the quantification of creatine kinase (CK-MB) and the femurs were removed for analysis by Raman, DXA, and F-max. A more pronounced increase in the bone mineral components was verified in the T group, for all the variables obtained by the Raman (calcium, phosphate, amide, and collagen). In addition, for animals submitted to GH supplementation, there was a reduction in the variable bone mineral density (BMD) obtained by the DXA (p < 0.05). Finally, the animals that received GH supplementation presented a higher F-max, but without statistical significance (p > 0.05). It was concluded that animals that received GH supplementation demonstrated a decrease in BMD. In addition, T alone was able to promote increased calcium, phosphate, amide, and collagen compounds in bone tissue.

Regulation of sclerostin in glucocorticoid-induced osteoporosis (GIO) in mice and humans.

Glucocorticoids (GC) are used for the treatment of inflammatory diseases, including various forms of arthritis. However, their use is limited, amongst others, by adverse effects on bone. The Wnt and bone formation inhibitor sclerostin was recently implicated in the pathogenesis of GC-induced osteoporosis. However, data are ambiguous. The aim of this study was to assess the regulation of sclerostin by GC using several mouse models with high GC levels and two independent cohorts of patients treated with GC. Male 24-week-old C57BL/6 and 18-week-old DBA/1 mice exposed to GC and 12-week-old mice with endogenous hypercortisolism displayed reduced bone formation as indicated by reduced levels of P1NP and increased serum sclerostin levels. The expression of sclerostin in femoral bone tissue and GC-treated bone marrow stromal cells, however, was not consistently altered. In contrast, GC dose- and time-dependently suppressed sclerostin at mRNA and protein levels in human mesenchymal stromal cells, and this effect was GC receptor dependent. In line with the human cell culture data, patients with rheumatoid arthritis (RA, n = 101) and polymyalgia rheumatica (PMR, n = 21) who were exposed to GC had lower serum levels of sclerostin than healthy age- and sex-matched controls (−40%, P < 0.01 and −26.5%, P < 0.001, respectively). In summary, sclerostin appears to be differentially regulated by GC in mice and humans as it is suppressed by GCs in humans but is not consistently altered in mice. Further studies are required to delineate the differences between GC regulation of sclerostin in mice and humans and assess whether sclerostin mediates GC-induced osteoporosis in humans.

Huo Xue Tong Luo capsule ameliorates osteonecrosis of femoral head through inhibiting lncRNA-Miat

Ethnopharmacological relevanceTraditional Chinese medicine has a long history of treating various bone diseases including osteoporosis and osteonecrosis etc. In clinical treatment, Huo Xue Tong Luo capsule (HXTL capsule) containing Peach kernel, Safflower carthamus, Angelica sinensis, Ligusticum wallichii etc, is one of the mostly used prescriptions for treating osteonecrosis of the femoral head (ONFH) with promising effects. ObjectivesThis study aims to identify the underlying molecular mechanism of how HXTL capsule exerts its function to ameliorate ONFH. Materials and methodsAll femoral bone tissues were collected during surgeries. Rat bone marrow mesenchymal stem cells (rMSCs) were used. Quantitative real time PCR was used to check the relative expression levels of genes. ChIP assay was performed to evaluate the binding of H3K4me3 and H3K27me3 in Miat promoter. ResultsWe showed that HXTL capsule promoted osteogenesis in rat MSCs as demonstrated by quantitative real time PCR and Alizarin Red S staining. Then we found silencing the endogenous lncRNA-Miat could promote osteogenesis of rMSCs. In addition, the ChIP assay showed that HXTL capsule significantly increased occupancy of H3K27me3 and decreased H3K4me3 in promoter regions of Miat, meaning HXTL capsule inhibited Miat expression through histone modifications. At last, by examining the femoral heads samples obtained from patients with ONFH during total hip arthroplasty surgery, we found the RNA level of hMiat in necrotic tissue was much higher than that of normal tissue. ConclusionsTaken together, our study shows that lncRNA-Miat might play an important role in pathogenesis of ONFH, and HXTL capsule can promote osteogenesis to ameliorate ONFH through inhibiting the transcriptional expression of Miat, at least partially.

The topography and proliferative activity of cells immunoreactive to various growth factors in rat femoral bone tissues after experimental fracture and implantation of titanium implants with bioactive biodegradable coatings.

Biodegradable implant coatings promote proliferation and expression of BMP-2, VEGF, and TGF-β2 genes and enhance BMP-2, VEGF, and TGF-β2 regulatory effects at different stages of reparative osteogenesis. To study the topography and ratio of PCNA-, VEGF-, BMP-2-, and TGF-β2-immunoreactive cells in rat femoral bone after closed fracture and implantation of titanium implants with biodegradable calcium phosphate and hydroxyapatite coatings. Standard titanium implant screws and similar implants with bioactive coatings were used. A total of 18 rats were randomly divided into three groups, two experimental and a control one. The rats in the first experimental group were implanted with implants without specific coating, while those in the second group, with implants with specific coatings. The control rats were subjected to the same fracture as the experimental ones without subsequent implantation. On days 7, 14, and 30 of experiment, the rats were sampled for histological examination. Histological sections were prepared and processed for PCNA, BMP-2, VEGF, and TGF-β2 immunoreactivity. In the regeneration zone, PCNA-immunoreactive cells substantially outnumbered other immunoreactive cell types. During the first two weeks after fracture, in the immediate vicinity of implant surface, the rate of VEGF production increased in osteoblast subpopulations and level of TGF-32 immunoreactivity decreased in chondroblasts. The level of TGF-32 was maximum on day 30 of experiment. BMP-2-immunoreactive osteocytes were found in the zone of external general plates. They accumulated at implants with calcium phosphate coating. Their number gradually increased by day 30 of experiment. The present data suggest that biodegradable implant coatings promote proliferation and expression of BMP-2, VEGF, and TGF-β2 genes and enhance BMP-2, VEGF, and TGF-β2 regulatory effects at different stages of reparative osteogenesis.

The Effect of Formalin Preservation Time and Temperature on the Material Properties of Bovine Femoral Cortical Bone Tissue.

Literature has reported controversial findings on whether formalin affected bone properties, or not, especially when different preservation time durations and temperatures were involved. Hence, accurately and systematically quantifying the effect of formalin on the mechanical properties of bone using a large dataset is crucial for assessing biomechanical responses based on fixed specimens. A total of 154 longitudinal and 149 transverse cuboid-shaped (12mm × 2mm × 0.5mm) specimens from themidsection of 12 bovine femora from six bovines were prepared and assigned to ten groups, including fresh-frozen, formalin-preserved at 25°C for 4weeks and 8weeks, and formalin-preserved at 4°C for 4weeks and 8weeks. All specimens underwent quasi-static three-point bending tests with a loading rate of 0.02mm/s. The Young's modulus, yield stress, yield strain, tangent modulus, effective plastic strain, ultimate stress, and toughness were calculated by optimizing the material parameters to make the force-displacement curve of the finite element prediction consistent with the experimental curve, combined with specimen-specific finite element models. Preservation time and temperature both had significant effects on the Young's modulus, yield stress, effective plastic strain, yield strain and ultimate stress of cortical bone (p < 0.05). The Young's modulus, yield stress, and ultimate stress of longitudinal specimens decreased significantly with the increase of preservation time, and the yield strain increased significantly. As the preservation temperature increases, the Young's modulus of the transverse sample decreased significantly, and the yield strain increased significantly. The preservation time mainly affects the longitudinal specimens, while the preservation temperature mainly affects the transverse specimens. Formalin preservation of bovine femoral cortical bones at alower temperature and less than 4weeks is recommended for biomechanical testing.

Expression of Sclerostin in Osteoporotic Fracture Patients Is Associated with DNA Methylation in the CpG Island of the SOST Gene.

Purpose SOST gene is one of the key factors in regulating bone absorption. Although there are reports showing diverse transcription factors, epigenetic modification could be responsible for regulating SOST gene expression. There is still little exploration on promoter methylation status of SOST gene in osteoporotic bone tissues. The aim of this study is to investigate the involvement of CpG methylation in regulation of SOST expression in patients with primary osteoporosis. Methods The diagnosis of osteoporosis was established on the basis of dual energy X-ray absorptiometry to measure BMD. All femoral bone tissues were separated in surgeries. After extracting total RNA and protein, we checked the relative expression levels of SOST by quantitative real-time PCR and western blot. Also, immunohistochemical staining was performed to observe the expression of SOST protein in the bone samples. The genomic DNA of non-OPF (non-osteoporotic fracture bone tissues) and OPF (osteoporotic fracture bone tissues) were treated by bisulfite modification, and methylation status of CpG sites in the CpG island of SOST gene promoter was determined by DNA sequencing. Results SOST gene expression in the non-OPF group was lower than that in OPF group. Bisulfite sequencing result showed that SOST gene promoter was slightly demethylated in the OPF group, as compared with non-OPF group. Conclusion Our study demonstrated that DNA methylation influenced the transcriptional expression of SOST gene, which probably may play an important role in the pathogenesis of primary osteoporosis.

Involvement of tumor necrosis factor alpha in steroid-associated osteonecrosis of the femoral head: friend or foe?

BackgroundThe etiology and pathology osteonecrosis of the femoral head (ONFH) are not completely clarified. As a cytokine participating in systemic inflammation, tumor necrosis factor alpha (TNFα) has been shown to be involved in the pathogenesis of ONFH. However, the role of TNFα in ONFH is not clearly clarified. In the present study, we investigated the effects of TNFα on proliferation, angiogenesis, and osteogenic differentiation of rat bone mesenchymal stem cells (rMSCs) and the underlying mechanisms.MethodsAll femoral bone tissues were separated in surgeries. After extracting total RNA and protein, we evaluated TNFα content by ELISA and the relative expression levels of genes by quantitative real-time PCR and western blot. Also, immunohistochemistry staining was performed to observe the expression of Runx2 in the bone samples. Chick embryo chorioallantoic membrane (CAM) assay was performed to observe the effect of TNFα on angiogenesis. The genomic DNAs were treated by bisulfite modification, and methylation status of CpG sites in the CpG islands of human and rat Runx2 gene promoter was determined by DNA sequencing. The binding of H3K4me3 and H3K27me3 in Runx2 promoter was checked by ChIP assay. RNA-seq analysis was used to find out the genes and pathways changed by TNFα in rMSCs.ResultsThe results demonstrate TNFα promotes cell proliferation and angiogenesis whereas inhibits osteogenesis. Epigenetic regulations including DNA methylation and histone modifications play important roles in mediating the effect of TNFα on osteogenic differentiation. We find an increased rate of CpG methylation in rat Runx2 promoter in TNFα-treated rMSCs, as well as significantly increased occupancy of H3K27me3 in Runx2 gene promoter. The content of TNFα in necrotic tissue is much lower than that of normal tissue. And relevantly, human Runx2 promoter is demethylated in necrotic tissue using bone samples from patient with ONFH. In addition, we have observed that Wnt signaling pathway is inhibited by TNFα as multiple Wnts are markedly decreased in TNFα-treated rMSCs by RNA-seq analysis.ConclusionTaken together, our study shows that TNFα plays complicated roles in the pathogenesis of ONFH, including proliferation, angiogenesis, and osteogenesis. Targeting TNFα should not be considered as an applicable strategy to inhibit the progression of ONFH.

Comparative chemical composition analysis of femoral condyles bone tissue in health and in deforming arthrosis

A comparative analysis of the chemical composition of the medial and lateral condyles of the femur in norm and with deforming arthrosis of the third degree is presented. It was found that when the bone tissue of the femur is degraded from the surface, a decrease in crystallinity is observed in depth, quantitative and qualitative changes in the organic bone matrix, in particular, a decrease in the proportion of the protein component, a change in the phase inorganic composition, and an increased degree of substitution of calcium in hydroxyapatite for ions of other metals. And the most dramatic changes are observed in bone tissue located near the pathologically deformed areas. It is shown that the data for normal bone tissue of the lateral and medial condyle of one specimen differ, which can be caused by different degrees of stress on the condyles themselves in the process of vital activity of the organism caused by asymmetry and a different shape of their articular surfaces. With deforming arthrosis in the surface layer of bone tissue, the concentration of calcium and a number of other metals increases, while the proportion of the protein component decreases. It was revealed that in the affected bone replacement of phosphate tetrahedra with carbonate ions occurs, as well as substitution of cations of divalent calcium with ions of other metals such as copper and manganese, and especially ferric cations. This breaks the overall structure of the crystal lattice of hydroxyapatite and affects the biomechanical properties of the surface, in particular, the reduction of trophism and the elasticity of the surface. In osteophyte tests, partial replacement of phosphate groups with carbonate groups occurs. Isomorphic structural substitutions caused by deposition of crystalline impurities lead to a change in the ratio of calcium and phosphorus concentrations. Excessive deposition of calcium salts leads to the formation of osteophytes.

Bone tissue loads around titanium femoral implant and coated with porous layer

Purpose: Difference in the mechanical properties of bone and stiffer femoral implant causes bone tissue resorption, which may result in implant loosening and periprosthetic fractures. The introduction of porous material reduces the stiffness of the implant. The aim of the study was to analyse the influence of porous shell of femoral revision implant on bone tissue loading distribution with use the finite element method. Design/methodology/approach: Load transfer in the femur has been investigated using the finite element method (Ansys). Cementless implant models were placed in the anatomical femur model. Femur model included sponge bone and cortical bone. The solid implant was compared with the implant containing porous material in 70% in outer layer with a thickness of 2 mm. Load of 1500 N during gait was simulated. In addition, the forces of the ilio-tibial band and the abductor muscles were implemented, as well as the torque acting on the implant. Findings: Increase of stress for the porous model was found. The underload zones in bone have been reduced. Loading distribution was slightly more favourable, albeit rather in cortical bone. Stress value in cancellous bone around cementless implant margin has increased to a level that is dangerous for bone loss. Stress in the implant was not dangerous for damage. The stress distribution was different in the implant neck zone where the porous shell borne a little less load and high stress was shifted to the stiffer core. Research limitations/implications: Variable conditions for fitting the stem to the bone as well as the friction conditions were not investigated. Practical implications: Stress values in the spongy bone around the insertion edge of the cementless implant are consistent with long-term clinical results of the bone atrophy in 1 and 2 Gruen`s zones around the fully porous implants. Originality/value: The advantage of fully porous coated implant was the decrease of risk of trabecular bone tissue resorption around the implant tip and the increase of risk of trabecular bone tissue resorption around insertion edge of the implant.

Effects of Nutritional Deficiency of Boron on the Bones of the Appendicular Skeleton of Mice.

Scientific evidence has shown the nutritional importance of boron (B) in the remodeling and repair of cancellous bone tissue. However, the effects of the nutritional deficiency of B on the cortical bone tissue of the appendicular skeleton have not yet been described. Thus, a study was performed to histomorphometrically evaluate the density of osteocyte lacunae of cortical bone of mouse femora under conditions of nutritional deficiency of B and to analyze the effects of the deficiency on the biomechanical properties of mouse tibiae. Weaning, 21-day-old male Swiss mice were assigned to the following two groups: controls (B+; n = 10) and experimental (B-; n = 10). Control mice were fed a basal diet containing 3mg B/kg, whereas experimental mice were fed a B-deficient diet containing 0.07mg B/kg for 9weeks. The histological and histomorphometric evaluations of the mice fed a B-deficient diet showed a decrease in the density of osteocyte lacunae in the femoral cortical bone tissue and the evaluation of biomechanical properties showed lower bone rigidity in the tibia.

BIOMECHANICAL RATIONALE FOR CHOICE OF CEMENT MANTLE THICKNESS AROUND A FEMORAL STEM

The change in mechanical properties of the femoral bone tissue surrounding hip endoprosthesis stems during the post-operative period is one of the causes of implant instability, and the mathematical description of this phenomenon is the subject of much research. In the present study, a model of bone adaptation, based on isotropic Stanford theory, is created for further computer investigation. The results of implementation of such a mathematical model are presented regarding the choice of cement mantle rational thickness in cemented hip arthroplasties. The results show that for cement mantle thicknesses ranging from 1–1.5[Formula: see text]mm, a peak stress value in the proximal part of the mantle exceeds the limit of durability of bone cement. Moreover, results show that high reduction in the bone density of distal and proximal regions was observed in cases of cement mantle thicknesses varying from 1–3[Formula: see text]mm. No significant changes in bone density of the abovementioned regions were obtained for 4[Formula: see text]mm and 5[Formula: see text]mm. The outcome of numerical investigations can be treated as valuable and will lead to the improvement of cemented hip replacement surgery results.

Curcumin Promotes Femoral Fracture Healing in a Rat Model by Activation of Autophagy.

BackgroundThe aim of this study was to use a rat model of femoral fracture healing to study the effects of curcumin on cell autophagy, compared with treatment with 3-methyladenine (3-MA), an inhibitor of autophagy.Material/MethodsThirty-six Sprague-Dawley rats with right mid-femoral fracture were divided into three groups: the curcumin-treated group (N=12) (gavage with curcumin 400 mg/kg/day); the curcumin + 3-MA-treated group (gavage with curcumin 400 mg/kg/day + 3-MA 30 mg/kg/day); and the control group (N=12) (gavage normal saline). Each group underwent femoral bone imaging using anteroposterior X-ray and micro-computed tomography (CT) at two weeks and six weeks following bone fracture. All rats were euthanized at the end of the study. Histology of the bone was performed to compare bone healing. Immunofluorescence and immunohistochemical tissue staining and Western blots were performed, to compare the expression of autophagy-related proteins, Beclin-1 and LC3-II.ResultsAutophagy of rat femoral bone tissue was activated following fracture, increasing with time, reaching a peak at 24 hours. Imaging and histology showed that curcumin promoted the fracture healing in rats, which was reduced by treatment with 3-MA. Immunohistochemistry, immunofluorescence, and Western blot showed that curcumin treatment increased the expression of Beclin-1 and LC3-II, which were reduced by treatment with the autophagy inhibitor, 3-MA.ConclusionsThe findings of this study, in a rat model of femoral bone fracture healing, showed that curcumin promoted bone healing and autophagy, which were reduced by treatment with 3-MA, a known inhibitor of autophagy.