Micro-computerized Tomography Scanning Research Articles

Enhanced bone formation of rat mandibular bone defects with collagen membranes loaded on bone morphogenetic protein-9

Background/purposeBone morphogenetic protein-9 (BMP-9) has demonstrated multiple advantages in promoting osteogenesis. Our previous findings have indicated that the use of an absorbable collagen membrane (ACM) as a carrier for growth factors is effective in stimulating bone regeneration. The objective of this study was to assess the synergistic impact of BMP-9 incorporated into ACM (ACM/BMP-9) on bone formation within rat mandibular bone defects. Materials and methodsCircular bone defects of critical size were surgically induced on both sides of the rat mandibular bone, with subsequent random allocation into distinct groups: control, ACM alone, and ACM loaded with low (0.5 μg) or high (2.0 μg) concentrations of BMP-9. We conducted real-time in vivo micro-computerized tomography scans at the baseline and at 2, 4, and 6 weeks, and measured the volume of newly formed bone (NFB), bone mineral density (BMD) of NFB, and the closure percentage of the NFB area. Histological and histomorphometric analyses were performed at 6 weeks. ResultsReal-time assessment revealed notably higher levels of bone volume, BMD, and closure percentage in the NFB area for the groups treated with ACM/BMP-9 compared to the control and ACM groups. Within the high concentration of BMP-9 group, the volume and BMD of NFB exhibited a significant increase at 6 weeks compared to baseline. Histological examination confirmed the existence of osteoblasts, osteocytes, and blood vessels within the NFB. ConclusionConsidering the limitations of this research, the real-time evaluation finding indicates that ACM/BMP-9 effectively promotes bone formation in critical-size mandibular defects in rats.

Regionalization and morphological integration in the vertebral column of Eurasian small-bodied newts (Salamandridae: Lissotriton).

Serially homologous structures may have complex patterns of regionalization and morphological integration, influenced by developmental Hox gene expression and functional constraints. The vertebral column, consisting of a number of repeated, developmentally constrained, and highly integrated units-vertebrae-is such a complex serially homologous structure. Functional diversification increases regionalization and modularity of the vertebral column, particularly in mammals. For salamanders, three concepts of regionalization of the vertebral column have been proposed, recognizing one, two, or three presacral regions. Using three-dimensional geometric morphometrics on vertebra models acquired with microcomputerized tomography scanning,we explored the covariation of vertebrae in four closely related taxa of small-bodied newts in the genus Lissotriton. The data were analyzed by segmented linear regression to explore patterns of vertebral regionalization and by a two-block partial least squares method to test for morphological integration. All taxa show a morphological shift posterior to the fifth trunk vertebra, which corresponds to the two-region concept. However, morphological integration is found to be strongest in the mid-trunk. Taken jointly, these results indicate a highly integrated presacral vertebral column with a subtle two-region differentiation. The results are discussed in relation to specific functional requirements, developmental and phylogenetic constraints, and specific requirements posed by a biphasic life cycle and different locomotor modes (swimming vs. walking). Further research should be conducted on different ontogenetic stages and closely related but ecologically differentiated species.

Widely targeted metabolic, physical and anatomical analyses reveal diverse defensive strategies for pseudobulbs and succulent roots of orchids with industrial value

Storage in pseudobulbs and succulent roots is vulnerable to attack from herbivores while play an important role in industrial utilization of orchids. However, we know little about the defensive strategies of pseudobulbs and succulent roots. Here, we characterized the possible physical and chemical defenses of pseudobulbs and succulent roots of five orchids with industrial value (Bletilla striata, Dendrobium chrysotoxum, Cymbidium tracyanum, C. sinense, and Acampe rigida) using X-ray micro-computerized tomography scanning and optical microscope observation as well as widely targeted metabolic profiling. We found that pseudobulbs and succulent roots of different orchid species combine different physical and chemical defensive strategies, and the relationship between defense and storage functions depend on species and age. Of the pseudobulbs of five species, C. tracyanum recruited the strongest defensive strategies, consisting of a thick epidermis, larger proportion of needle-like calcium oxalate crystals, and higher content of alkaloids and quinones. The pseudobulbs of C. sinense had a higher proportion of vascular bundle, and those B. striata had the strongest tissue biomechanical resistance. However, pseudobulbs of D. chrysotoxum were the most vulnerable to herbivores with relatively higher nutrient content and weaker defensive protection. For the succulent roots of five species, A. rigida had the strongest storage ability, and correspondingly the most chemical defensive components, while a thicker velamen and higher proportion of needle-like calcium oxalate crystals were found in the roots of C. tracyanum and C. sinense respectively. Our results suggest that diverse combinations of defensive strategies play a role protecting pseudobulbs and succulent roots of orchids from biotic stress. These findings contribute to the cultivation management of orchids with industrial value.

Real-time assessment of guided bone regeneration in critical size mandibular bone defects in rats using collagen membranes with adjunct fibroblast growth factor-2

Background/purposeFibroblast growth factor-2 (FGF-2) regulates bone formation. The concept of guided bone regeneration using a resorbable collagen membrane (RCM) is generally accepted in implant dentistry. This study aimed to investigate the bone healing pattern in rat mandibular bone defects in real-time with and without RCM containing FGF-2 (RCM/FGF-2). Materials and methodsCritical-size circular bone defects (4.0 mm diameter) were created on both sides of the rat mandibular bone. The defects were randomly divided into the following groups: control, RCM alone, RCM containing low (0.5 μg) or high (2.0 μg) concentration of FGF-2. We performed real-time in vivo micro-computerized tomography scans at the baseline and at 2, 4, and 6 weeks, and measured the volume of newly formed bone (NFB), bone mineral density (BMD) of NFB, and the closure percentage of the NFB area. At 6 weeks, the mandibular specimens were assessed histologically and histomorphometrically to evaluate the area of new bone regeneration. ResultsReal-time assessment revealed a significant increase in the volume, BMD, and closure percentage of the NFB area in the RCM/FGF-2-treated groups than that in the control and RCM groups. In the H-FGF-2 group, the volume and BMD of NFB exhibited a significant increase at 6 weeks than that at the baseline. Histological evaluation revealed the presence of osteoblasts, osteocytes, and blood vessels within the NFB. ConclusionThe real-time in vivo experiment demonstrated that RCM/FGF-2 effectively promoted bone regeneration within the critical-size mandibular defects in rats and verified new bone formation starting in the early postoperative phase.

Active bone material containing modified recombinant human bone morphogenetic protein 2 induces bone regeneration in the alveolar process cleft in rabbits.

The clinical application of most materials used to fill severe bone defects is limited owing to the insufficient ability of such materials to induce bone regeneration over a long repair period. The purpose of this study was to establish a model for the alveolar process cleft in rabbits to evaluate the effect of active bone material in bone defect repair. The active bone material used in this study is a new bone repair material composed of a heterogeneous collagen membrane implanted with modified recombinant human bone morphogenetic protein 2. This proposed active bone material can specifically bind to collagen. Twenty-four young Japanese white rabbits (JWRs) were selected and randomly divided into four groups (normal, control, material, and bone morphogenetic protein groups). The alveolar process cleft model was established by removing an equal volume bone at the left maxillary position. Blood samples were collected from the JWRs 3 and 6months after the surgery to evaluate the biocompatibility of the active bone materials. Subsequently, the skull model was established, and the appearance was observed. Imaging methods (including X-ray examination and micro-computerized tomography scanning), tissue staining, and immunohistochemistry were employed for the evaluation. The bone collagen material and active bone material exhibited high biocompatibility. In addition, the ability of the active bone material to induce bone repair and regeneration was higher than that of the bone collagen material. The active bone material exhibited satisfactory bone regeneration performance in rabbits, indicating its potential as an active material for repairing congenital alveolar process clefts in humans.

Melatonin Suppresses Estrogen Deficiency-Induced Osteoporosis and Promotes Osteoblastogenesis by Inactivating the NLRP3 Inflammasome.

Postmenopausal osteoporosis induced by estrogen deficiency causes inadequate new bone formation and affects millions of women worldwide. Melatonin can improve bone mineral density at the femoral neck in postmenopausal women with osteopenia. This study aimed to investigate the mechanism of melatonin in estrogen deficiency-induced osteoporosis by focusing on osteoblast differentiation. 12-week-old female C57BL/6J mice were ovariectomized (OVX) and intraperitoneally injected with 10 or 50mg/kg of melatonin for 8weeks. Micro-computerized tomography scanning demonstrated that melatonin alleviated OVX-induced bone loss in a dose-dependent manner. Serum levels of ALP and osteocalcin (OCN) were further increased, whereas tartrate-resistant acid phosphatase level was decreased by melatonin in OVX-treated mice. Melatonin promoted osteoblast differentiation in primary bone marrow mesenchymal stem cells from OVX mice. It also inhibited activation of NLRP3 inflammasome in femoral bone protein and in induced osteoblasts stimulated by OVX. Knockdown of NLRP3 attenuated OVX-induced repression of osteogenic differentiation. The NLRP3 inflammasome activator monosodium urate partly abrogated the effect of melatonin on the expression of osteoblastogenic markers, including Runx2 and OCN. Additionally, the results showed that melatonin suppressed NLRP3 inflammasome activation by regulating Wnt/β-catenin signaling, which was confirmed by the Wnt/β-catenin inhibitor recombinant DKK1. These results indicated that melatonin ameliorates estrogen deficiency-induced osteoporosis and impaired osteogenic differentiation potential by suppressing activation of the NLRP3 inflammasome via mediating the Wnt/β-catenin pathway.

Uni-Directional Transportation on Peristome-Mimetic Surfaces for Completely Wetting Liquids.

Liquid uni-directional transport on solid surface without energy input would advance a variety of applications, such as in bio-fluidic devices, self-lubrication, and high-resolution printing. Inspired by the liquid uni-directional transportation on the peristome surface of Nepenthes alata, here, we fabricated a peristome-mimicking surface through high-resolution stereo-lithography and demonstrated the detailed uni-directional transportation mechanism from a micro-scaled view visualized through X-ray microscopy. Significantly, an overflow-controlled liquid uni-directional transportation mechanism is proposed and demonstrated. Unlike the canonical predictions for completely wetting liquids spreading symmetrically on a high-energy surface, liquids with varied surface tensions and viscosities can spontaneously propagate in a single preferred direction and pin in all others. The fundamental understanding gained from this robust system enabled us to tailor advanced micro-computerized tomography scanning and stereo-lithography fabrication to mimic natural creatures and construct a wide variety of fluidic machines out of traditional materials.

Myeloid thrombomodulin lectin-like domain inhibits osteoclastogenesis and inflammatory bone loss.

Osteoclastogenesis is an essential process during bone metabolism which can also be promoted by inflammatory signals. Thrombomodulin (TM), a transmembrane glycoprotein, exerts anti-inflammatory activities such as neutralization of proinflammatory high-mobility group box 1 (HMGB1) through TM lectin-like domain. This study aimed to identify the role of myeloid TM (i.e., endogenous TM expression on the myeloid lineage) in osteoclastogenesis and inflammatory bone loss. Using human peripheral blood mononuclear cells and mouse bone marrow-derived macrophages, we observed that the protein levels of TM were dramatically reduced as these cells differentiated into osteoclasts. In addition, osteoclastogenesis and extracellular HMGB1 accumulation were enhanced in primary cultured monocytes from myeloid-specific TM-deficient mice (LysMcre/TMflox/flox) and from TM lectin-like domain deleted mice (TMLeD/LeD) compared with their respective controls. Micro-computerized tomography scans showed that ovariectomy-induced bone loss was more pronounced in TMLeD/LeD mice compared with controls. Finally, the inhibiting effects of recombinant TM lectin-like domain (rTMD1) on bone resorption in vitro, and bone loss in both the ovariectomized model and collagen antibody-induced arthritis model has been detected. These findings suggested that the myeloid TM lectin-like domain may inhibit osteoclastogenesis by reducing HMGB1 signaling, and rTMD1 may hold therapeutic potential for inflammatory bone loss.

Treatment with QiBaoMeiRan, a Chinese herbal formula, prevents bone loss in ovariectomized rat

ABSTRACTObjective Hormone replacement therapy has been used as an effective treatment for the prevention of bone loss in postmenopausal women. In our previous study, QiBaoMeiRan formula (QBMR) had estrogenic activity and could relieve symptoms of hot flushes and body weight increase induced by estrogen decline. However, no evidence base links QBMR to preventing bone loss. The aim of this study is to investigate the effect of QBMR on bone loss.Methods The ovariectomized rat model was established, and ovariectomized rats were treated with QBMR at doses of 0.875, 1.75, and 3.5 g/kg per day for 8 weeks. Biochemical parameters, bone mineral density, structural morphometric traits and histological characteristics of trabecular bone were assessed.Results QBMR treatment significantly decreased the increase in serum alkaline phosphatase, bone Gla-protein and C-telopeptide fragments of type I collagen and decreased the decline of serum calcium and phosphorus in the circulation of ovariectomized rats. QBMR completely corrected the decrease in bone mineral density in lumbar vertebrae (L4–L6) comparable to the sham group. In addition, QBMR treatment also significantly ameliorated the decrease of structural parameters of femur trabecular bone, bone volume fraction, trabecular number, trabecular thickness and bone mineral density as well as the increase in trabecular separation by micro-computerized tomography scanning. These were also confirmed by bone histological results that showed its protective action.Conclusions Our results indicated that QBMR had a definite anti-bone loss effect and will have potential to be used for the treatment of postmenopausal osteoporosis.

Microscale solute transport and precipitation in complex rock during drying

AbstractFormation drying and salt precipitation due to gas injection or production can have serious consequences for upstream operations in terms of injectivity and productivity. Recently, evidence has been found that the complexity of the pore space and microscopic capillary‐driven solute transport plays a key role in the relationship between permeability and porosity. In this study, we investigate drying and salt precipitation due to supercritical CO2 injection in single‐porosity and multiporosity systems under near well‐bore conditions. We image fluid saturation states and salt deposition by means of microcomputerized tomography scanning during desaturation. We observe capillary‐driven transport of brine and the respective solutes on the pore scale. Solute transport between porosity classes determines the distribution of the deposits in the pore space and the permeability porosity relationships—K(φ)—for flow‐through drying.

Internal damage investigation of the impacted glass/glass+aramid fiber reinforced composites by micro-computerized tomography

This paper utilizes the micro-computerized tomography as the non-destructive inspection technique to characterize and compare damage modes of glass and glass+aramid fiber reinforced polyester laminated composites. Main goal of this study is to visualize the internal impact damage variation due to reinforcement type by using micro-computerized tomography scanning. Impact tests were performed on glass fiber reinforced and glass fiber+aramid fiber reinforced polyester composites at the same conditions and both composites were tested at 80J energy. After low velocity impact tests, micro-computerized tomography scans of both composites were taken from SkyScan 1173 system.

Assessment of biocompatibility and initial evaluation of genipin cross-linked elastin-like polypeptides in the treatment of an osteochondral knee defect in rabbits

Polypeptides based on the alternating hydrophobic and cross-linking domain structure of human elastin are capable of undergoing self-assembly to produce polymeric matrices with unique biological and mechanical properties. Here, we test the initial feasibility of using a genipin cross-linked elastin-based material as an acellular plug in the treatment of an osteochondral defect in the rabbit knee. Full-thickness defects in the weight-bearing surface of the medial femoral condyle in 18 New Zealand White rabbits were surgically produced and press fitted with cylindrical pads composed of genipin cross-linked elastin-like polypeptides, with identical wounds in the opposite knee left untreated as controls. The biocompatibility of the material, overall wound healing and regeneration of subchondral tissue was assessed at 2, 4 and 6 weeks by histological evaluation, synovial fluid analysis and microcomputerized tomography scanning. Histological analysis revealed the regeneration of subchondral bone at the periphery of the material, with evidence of hyaline-like overgrowth across the apical surface in 11/16 cases. Pads developed tight contacts with host tissue and appeared completely biocompatible, with no evidence of localized immune response or increased inflammation compared to controls. The material was stable to 6 weeks, with an aggregate elastic modulus calculated at ∼470 kPa when tested under confined compression. Further studies are required to assess material degradation over time and long-term replacement with repair tissue.

三维显微CT扫描系统的X射线源焦点投影坐标测量方法

三维显微CT扫描系统的X射线源焦点投影坐标测量方法

Spatial and temporal patterns of bone formation in ectopically pre-fabricated, autologous cell-based engineered bone flaps in rabbits.

Biological substitutes for autologous bone flaps could be generated by combining flap pre-fabrication and bone tissue engineering concepts. Here, we investigated the pattern of neotissue formation within large pre-fabricated engineered bone flaps in rabbits. Bone marrow stromal cells from 12 New Zealand White rabbits were expanded and uniformly seeded in porous hydroxyapatite scaffolds (tapered cylinders, 10–20 mm diameter, 30 mm height) using a perfusion bioreactor. Autologous cell-scaffold constructs were wrapped in a panniculus carnosus flap, covered by a semipermeable membrane and ectopically implanted. Histological analysis, substantiated by magnetic resonance imaging (MRI) and micro-computerized tomography scans, indicated three distinct zones: an outer one, including bone tissue; a middle zone, formed by fibrous connective tissue; and a central zone, essentially necrotic. The depths of connective tissue and of bone ingrowth were consistent at different construct diameters and significantly increased from respectively 3.1 ± 0.7 mm and 1.0 ± 0.4 mm at 8 weeks to 3.7± 0.6 mm and 1.4 ± 0.6 mm at 12 weeks. Bone formation was found at a maximum depth of 1.8 mm after 12 weeks. Our findings indicate the feasibility of ectopic pre-fabrication of large cell-based engineered bone flaps and prompt for the implementation of strategies to improve construct vascularization, in order to possibly accelerate bone formation towards the core of the grafts.

Radiologic characterization of new bone generated from distraction after maxillary bone transport.

The purpose of this study was to characterize the radiologic features of the new bone generated from distraction following maxillary bone transport. Maxillary dentoalveolar segments were transported by distraction to close posterior maxillectomy defects in 9 rhesus monkeys. The distracted dentoalveoli were harvested at 1, 2, 3, and 6 months after the completion of the distraction. The specimens were evaluated by plain radiography and microcomputerized tomography scanning, which included 2- and 3-dimensional quantitative analyses of bone regeneration volume and microstructural indices. Plain radiographs showed that radiolucency in the distraction regenerate reduced with time. Microcomputerized scanning found that bone formation and trabecular thickness increased in the new bone with longer consolidation. The high orientation and connectivity of the trabeculae were reduced at longer consolidation intervals. Within the whole distraction gap, bone volume was found to be site-specific. Morphologic analysis in the high resolution offered by microcomputerized tomography shows that active bone mineralization and remodeling occur in the new bone within 3 months after distraction in maxillary dentoalveolus.