Arrangement Of Collagen Fibers Research Articles

Efficacy of non-ablative fractional laser at different energy and density in the early treatment of hyperplastic scars in a rabbit ear model: a clinical observation

Objective To preliminarily optimize the energy and density of laser radiation for the early treatment of hyperplastic scars in a rabbit ear model, and to explore possible therapeutic mechanisms. Methods Sixty-one hyperplastic scars were successfully established on the ears of 10 healthy New Zealand white rabbits with large ears, and randomly divided into 2 groups: 1-week group (30 scars) and 3-week group (31 scars) . These 2 groups were separately divided into 5 subgroups: group A treated with laser at a density of 100 PPA and an energy of 10 mJ, group B with laser at a density of 100 PPA and an energy of 50 mJ, group C with laser at a density of 169 PPA and an energy of 10 mJ, group D with laser at a density of 169 PPA and an energy of 50 mJ, and group E receiving no treatment. There were 6 scars in each group, except the group E in the 3-week group. Two healthy New Zealand white rabbits with large ears were not subjected to modeling, and served as group F (blank control group) . Immunohistochemical study was performed to determine the expression of matrix metalloproteinase (MMP) -13 in the skin tissues from the rabbit ears 1 week after the treatment. Three weeks after the treatment, the skin tissues from the rabbit ears were subjected to hematoxylin-eosin (HE) staining and Masson staining. Then, the structure of scars was observed, and scar elevation index was calculated. Statistical analysis was carried out by Kruskal-Wallis H test for the comparison of scar elevation index, and by one-way analysis of variance (ANOVA) for the comparison of the average absorbance value of MMP-13. Results As HE staining revealed, the groups A, B, C and D all showed thicker dermis and increased number of collagen fibers compared with the group F (normal skin tissues) , but showed thinner dermis, decreased number and more ordered arrangement of collagen fibers compared with the group E (untreated scar tissues) . No obvious difference was observed in the thickness of the dermis among the groups A, B, C and D. The scar elevation index significantly differed among the 6 groups (H= 22.757, P 0.05) . Conclusions Non-ablative fractional laser is effective for the treatment of early-stage hyperplastic scars. At the same laser density, 50-mJ laser was superior to 10-mJ laser for the treatment of hyperplastic scars, likely because high-energy laser can stimulate the recombi-nation of extracellular matrices and up-regulated MMP-13 expression to a greater extent. Key words: Cicatrix, hypertrophic; Lasers; Matrix metalloproteinase 13; Fractional laser; Energy

Suppressive effect of bacoside A on hypertrophic scar formation by downregulation of TGF-β1

Purpose: To determine the anti-scarring property of bacoside A (BA) in a rabbit model of post-burns hypertrophic scar (HS). Methods: A total of 16 healthy male rabbits were divided into four groups (4 rabbits/group). The rabbits were subjected to full-thickness burn wound by placing a 10-mm brass rod at 90 oC on their ears for 20s, and were untreated (HS group). The remaining rabbits also underwent HS process but were topically treated daily with 0.2, 0.4 or 0.6 % BA gel (HS + 0.2, 0.4, and 0.6 % BA groups) from day 8 to day 34. Results: The mean values of collagen (types I & III), hydroxyproline (precursor of collagen) and hexosamine, as well as scar index significantly (p < 0.001) decreased after 28 days of topical treatment with BA. Moreover, BA application resulted in improved histological changes with proper arrangement of collagen fibers. Significant (p < 0.001) upregulation or downregulation of transforming growth factor beta-1 (TGF-β1) and matrix metalloproteinase-1 (MMP-1) were observed in the BA-treated rabbits. Conclusion: Treatment with BA significantly lowers the scarring area of burn wounds by downregulation of TGF-β1. Thus, BA can potentially be developed into a drug for managing injury scars. Keywords: Hypertrophic scar, Bacoside A, Scar elevation index, Transforming growth factor beta-1, Collagen

Discoid lateral meniscus in children and adolescents: a histological study

BackgroundDiscoid lateral meniscus is the most frequent variant of the meniscus. Although the histology of normal menisci in children and in adults has been well described, few studies have focused on the histology of discoid menisci. Furthermore, most of the patients in those studies were adults. The aim of the present study was to report the histological findings of discoid lateral meniscus in a group of children and adolescents, aged between 9 and 18, after arthroscopic partial resection, focusing on cellularity, arrangement of collagen fibers, and vascularity of the excised fragments. Furthermore, to report on MRI findings compared to the histological findings in the same region.MethodsSix patients (one female and five males) aged 9, 10, 13, 15, 17, and 18, were arthroscopically operated on partial meniscectomy (saucerization) of a discoid lateral meniscus, and the specimens were histologically examined.ResultsThe extracellular matrix showed a different distribution and characteristics depending on the different side of the meniscus. Irregularly oriented collagen fibers in discoid lateral meniscus were found. There were no blood vessels in the inner part of discoid lateral meniscus in all patients but the 18-year old (in which we observed also endothelials cells, edematous tissue and leaking of erythrocytes in the extracellular matrix). In the discoid lateral menisci analyzed, irregularly oriented collagen fibers with blood vessels were found only in the presence of degenerating tissue.ConclusionsDiscoid lateral meniscus is different from a normal meniscus in terms of vascularity and disorganization of collagen fibers.

COMPARATIVE CHARACTERISTIC OF MORPHOLOGICAL CHANGES AND PHENOTYPIC MARKERS OF DISPLASIA OF CONNECTIVE TISSUE IN CHILDREN WITH VARIOUS UROLOGICAL AND ANDROLOGICAL PATHOLOGY

The increase in the number of urological and andrological diseases associated with undifferentiated connective tissue dysplasia dictates the need to study this problem in childhood. The present study was aimed at analyzing the phenotypic manifestations of undifferentiated connective tissue dysplasia, as well as the severity of the morphological changes in its structures in children with various urological and andrological pathology, that constituted the main observation group. As a control group, children with a similar pathology of the genitourinary system without signs of mesenchymal insufficiency were examined. Comparative analysis of the detection of the number of phenotypic markers as one of the indicators of connective tissue dysplasia in children with various nosological forms from the urological department made it possible to determine the prevalence rate of the number of phenotypes in patients with hypospadia, varicocele and congenital edema of the testicle, and in the highest percentage of cases - in patients with hypospadias. Craniocephalic anomalies and small anomalies of the oral cavity were diagnosed most frequently. In a smaller percentage of cases, stigmata of the auricles and the osteoarticular system were identified. Phenotypic manifestations of dysplasia in the form of eye anomalies, pathology of the skin and its appendages - were noted even less often. The morphological confirmation of undifferentiated connective tissue dysplasia in the examined patients was the detection of dystrophy of collagen and elastic fibers, detected by means of microscopy. At the same time, a characteristic sign of dysplasia was the chaotic arrangement of collagen fibers, their thickening and discontinuity. Staining for elastin allowed detecting the uneven arrangement, curvature or fragmentation of elastic fibers. In the work, there was made a study of the features of morphological changes in connective tissue structures, depending on the nosological form. With this aim, we divided various histological signs of mesenchymal insufficiency, revealed during microscopy, in three degrees of the severity. Histological studies of connective tissue structures confirmed the predominance of more pronounced morphological manifestations of dysplasia in patients with hypospadias. They had severe dystrophic changes in 70% of cases, while such abnormalities in children operated for varicocele, were noted in every fourth biopsy, and in hydrops patients - only in 15% of cases. The study of collagen and elastic fibers of dermal preparations resected during surgical interventions in children with phimosis against the background of dysplasia syndrome showed no significant pathological changes. In biopsies of this group of patients, there were only minimal manifestations of mesenchymal insufficiency. In children with urological and andrological pathology without signs of undifferentiated dysplasia, morphological disturbances in structural components of connective tissue corresponding to mild severity were noted. Thus, the performed analysis of manifestations of connective tissue dysplasia in children with various urological and andrological pathology showed the prevalence of the number of phenotypic markers and the severity of morphological changes in children with hypospadias. Less severe manifestations of dysplasia were noted in patients with varicocele and hydrocele. The study of signs of connective tissue insufficiency in the group of patients with phimosis showed their minimal manifestations.

Effect of rat adipose-derived mesenchymal stem cells on macrophages phenotype in skin wound

Objective To investigate the effect of local injection of rat adipose-derived mesenchymal stem cells (ADSCs)on the phenotype of macrophages in skin wound. Methods The cryopreserved primary SD rat ADSCs were resuscitated and then sub-cultured. ADSCs of the third generation were used in the experiments. Thirty six SD rats were divided into ADSCs group (n=18) and control group(n=18) by random numbers table method. The full thickness skin wounds were established on both sides of the spine. After the model establishment 0.2 ml ADSCs suspension labeled by live cell stain Chloromethylbenzamido derivatives of 1, 1'-dioctadecyl-3, 3, 3', 3'-tetramethylindo-carbocyanine perchlorate (CM-Dil) with the concentration of 5×106/ml was subcutaneously annularly injected in the skin wound of SD rats in ADSCs group. The SD rats in control group were given 0.2 ml serum-free Dulbecco modified Eagle medium (DMEM). On 3, 7, and 14 days after injury, six rats were selected from each group to measure the wound area and healing rate. The healed wound tissues were harvested to observe the morphology by HE staining. The expressions of interleukin (IL)-10 were detected by immunohistochemistry staining. The double-positive expressions of CD68 and inducible nitric oxide synthase (iNOS) (M1 type macrophages) and of CD68 and arginase-1 (Arg-1) (M2 type macrophages) were detected by immunofluorescent staining. The distribution of CM-Dil-labeled ADSCs in healed wound tissue 14 days after injury was observed by inverted fluorescence microscope. Results (1) At day 3 after injury, the wound areas in two groups were covered with crust and surrounding redness, and the wound healing rates were slightly different; at day 7 after injury, the wound area of ADSCs group was significantly smaller than that of control group, and the healing speed and rate of ADSCs group was significantly higher than that of control group (P<0.01); at day 14 after injury, the healing rate of ADSCs group was nearly 99% (P<0.01), and the healing skin tissue texture of ADSCs group was better than that of control group. (2) At day 3 after injury, there were a large number of inflammatory cells and disorganized collagen fiber in the wound areas of two groups; at day 7 after injury, the inflammatory cells infiltration reduced in ADSCs group compared with control group, and the collagen fiber arrangement in control group was in disorder; at day 14 after injury, the inflammatory cells in both groups obviously decreased, and ADSCs group had more new vessels and more orderly arrangement of collagen fiber than control group. CM Dil labeled ADSCs were seen in the healing wound tissue in ADSCs group. (3) At day 3 after injury, there was little difference in M1 type macrophage distribution in the two groups; ADSCs group had more M2 type macrophage cells than control group significantly (P<0.01); the expression of IL 10 in ADSCs group was not high, which did not differ from that of control group; at days 7 and 14 after injury, ADSCs group has fewer M1 type macrophage cells, more M2 type macrophage cells, and higher expressions of IL-10 than control group (P<0.01). Conclusion The ADSCs trasplantation can promote the change from M1 type to M2 type macrophages, facilitating wound regeneration and healing. Key words: Mesenchymal stem cells; Macrophages; Wound healing

Morphogenesis of aligned collagen fibers in the annulus fibrosus: Mammals versus avians

The mammalian intervertebral disc (IVD) consists of a gel-like, disordered nucleus pulposus (NP) surrounded by a highly ordered collagen structure, the annulus fibrosus (AF). While this concentric array of lamellae has been amply studied, its physical origin is poorly understood. The notochord is a rod-like organ located in the mid-line of the growing embryo and plays an essential role in IVD development. The aim of this study was to elucidate the effect of notochord development on the collagen fiber arrangement evolution in the AF. To that end, we studied IVD development in mouse embryos and compared these observations to those from chicken embryos, which do not form the typical laminar structure around the NP. In mouse, cross-aligned collagen arrangement of the AF forms from the sclerotome upon bulging of the notochord to become NP. By contrast, the notochord in the chicken embryo swells substantially without the physical restrictions of the future vertebrae and thus do not bulge. From these observations, we conclude that physical and geometrical constrictions are essential for the formation of the highly structured AF.

Aligned Collagen Scaffolds Enhance Tenogenic Differentiation of Bone Marrow-Derived Stem Cells

Tendon repair remains a formidable challenge in clinic, due to its limited function in long-term recovery. Decellularized native tendon extracellular matrix (ECM), which contains specific bioactive factors and a large number of collagen fibers, seeded with bone marrow-derived stem cells (BMSCs) has been found to promote tendon neogenesis. However, the effect of arrangements of natural collagen fibers on the differentiation of BMSCs remains unclear. Here, we prepared aligned collagen fiber scaffolds from rat tail tendon ECM to investigate the effect of collagen arrangements on the morphology, proliferation and differentiation of rat BMSCs in vitro. It was found that BMSCs were elongated and aligned along the collagen fibers on the aligned collagen fibers. Furthermore, the aligned collagen scaffolds significantly enhanced the expression of tenocyte markers TNMD and THBS4. The results indicated that aligned collagen scaffolds could induce the tenogenesis of BMSCs, which would provide an alternative approach for tendon tissue engineering.

Regional Collagen Fiber Network in the Articular Disc of the Human Temporomandibular Joint: Biochemical 3-Tesla Quantitative Magnetic Resonance Imaging Compared to Quantitative Histologic Analysis of Fiber Arrangement.

To evaluate the regional collagen fiber network in the human temporomandibular joint (TMJ) disc by using biochemical magnetic resonance imaging (MRI) and quantitative histology. MRI of 5 heads (10 TMJ discs) obtained from partially dentate or edentulous cadavers was performed at 3-Tesla MRI by using a flexible, 8-channel transmit-receive coil. After MRI, all 10 discs were processed histologically. Percentages of coronal, sagittal, and transverse collagen fibers were assessed stereologically for the anterior, central, and posterior parts of the disc. An anisotropy index was calculated for collagen fiber arrangement in all three regions of interest. In the central part of the TMJ disc, collagen fibers were arranged anisotropically with a preferentially sagittal direction. In the anterior and posterior parts, evidence for fibers being arranged isotropically (randomly) without preferred direction was found. Mean MRI T2 values appeared to be correlated with the anisotropy index of collagen fibers (r = -0.45; P < .05). When tested individually, T2 values of the isotropic anterior and posterior disc regions showed a partial but significant correlation with the anisotropy index of collagen fibers (r = -0.54; P < .05), whereas the anisotropic central part did not (P > .05). This study has provided the first systematic comparison of quantitative data on collagen fiber isotropy and anisotropy assessed in histologic sections with biochemical quantitative MRI for human TMJ fibrous cartilage.

Development of a Porcine Full-Thickness Burn Hypertrophic Scar Model and Investigation of the Effects of Shikonin on Hypertrophic Scar Remediation.

Hypertrophic scars formed after burns remain a challenge in clinical practice. Development of effective scar therapies relies on validated animal models that mimic human hypertrophic scars. A consistent porcine full-thickness burn hypertrophic scar model has yet to be developed. We have previously reported that Shikonin induces apoptosis and reduces collagen production in hypertrophic scar fibroblasts in vitro and may therefore hold potential as a novel scar remediation therapy. In this study, we aimed to validate the potential of Shikonin on scar remediation in vivo. A novel porcine hypertrophic scar model was created after full-thickness burn wounds, and the effect of Shikonin on scar remediation was investigated. Clinical scar assessments, histology, and immunohistochemistry were used to evaluate scar appearance, morphology, and protein expression. Eight weeks after scar formation, clinical scar assessment indicated that the score of hypertrophic scars treated with Shikonin was significantly lower than that of the control group. Hypertrophic scars treated with Shikonin appeared flat, pink, and pliable. In addition, histological analysis indicated that hypertrophic scars treated with Shikonin exhibited reduced thickness of the epidermis and dermis, thin and even epithelial layers, reduced numbers of keratinocytes, uniform distribution of fibroblasts, and a parallel and loose arrangement of collagen fibers in the dermis. Moreover, immunohistochemical analysis indicated that Shikonin inhibited the expression of p63, cytokeratin 10, alpha-smooth muscle actin, transforming growth factor-beta 1, and collagen I, which play important roles in hypertrophic scar formation. Based on these results, we conclude that Shikonin has potential as a novel scar therapy.

Comparative Study on Surface Geometric Properties of Decellularized and Glutaraldehyde fixed Bovine Pericardium and Possible Effects on Cell Seeding

Background:Collagen fibers arrangement and density play a pivotal role in cell migration and proliferation. Bovine Pericardium (BP) is a collagen – rich tissue which is currently used as a biological scaffold.Aim of the work:The aim of this study was to examine the effects of the decellulrazation processes on the surface architecture and geometry of the BP and consequently cell seeding and epitheliliazation onto it.Methods and Results:To achieve these goals bovine pericardium (BP) was decellularized with 1 % TritonX-100 and 0.1 % sodium dodecyl sulfate . Control group was only treated by PBS and post fixed in glutaraldehyed (GAD) 1%. The buccal cell suspensions were then overlaid on the serous side of the BP scaffolds at concentrations2×105 Cells/mL. 10 days following seeding the samples were fixed and SEM results were analyzed by Matlab software. The pore surfaces were measured 182.05±11.61μm2 and 132.44±12.35 μm2 in acellular and GAD BP respectively (P<0.05). The con surfaces were measured 93.54±13.41 μm2and 114.78±11.67 μm2 acellular and GAD PB respectively (P<0.05).The thickness of collagen bundles in decellularized BP and GAD BP (10 random fields) were obtained 19.5±6.3 μm and 16.8±.99 μm respectively (p<0.05).Conclusion: The results of acellular group showed more attached cells onto scaffold, epithelialization growth, and spreading on the scaffold. While in contrast GAD-fixed group only scattered cell clumping were seen. Our findings showed that topographical changes after decellularization could provide a suitable growth pool or microenvironment, that can influence cellular attachment and subsequently cell-ECM integration in biological scaffold.

Photobiomodulation of a flowable matrix in a human skin ex vivo model demonstrates energy-based enhancement of engraftment integration and remodeling.

The use of dermal substitutes to treat skin defects such as ulcers has shown promising results, suggesting a potential role for skin substitutes for treating acute and chronic wounds. One of the main drawbacks with the use of dermal substitutes is the length of time from engraftment to graft take, plus the risk of contamination and failure due to this prolonged integration. Therefore, the use of adjuvant energy-based therapeutic modalities to augment and accelerate the rate of biointegration by dermal substitute engraftments is a desirable outcome. The photobiomodulation (PBM) therapy modulates the repair process, by stimulating cellular proliferation and angiogenesis. Here, we evaluated the effect of PBM on a collagen-glycosaminoglycan flowable wound matrix (FWM) in an ex vivo human skin wound model. PBM resulted in accelerated rate of re-epithelialization and organization of matrix as seen by structural arrangement of collagen fibers, and a subsequent increased expression of alpha-smooth muscle actin (α-SMA) and vascular endothelial growth factor A (VEGF-A) leading to an overall improved healing process. The use of PBM promoted a beneficial effect on the rate of integration and healing of FWM. We therefore propose that the adjuvant use of PBM may have utility in enhancing engraftment and tissue repair and be of value in clinical practice.

MiR-155 inhibits the formation of hypertrophic scar fibroblasts by targeting HIF-1α via PI3K/AKT pathway

Hypertrophic scar (HS) is a serious skin fibrotic disease characterized by the excessive proliferation of fibroblasts and often considered as a kind of benign skin tumor. microRNA-155 (miR-155) is usually served as a promising marker in antitumor therapy. In view of the similarities of hypertrophic scar and tumor, it is predicted that miR-155 may be a novel therapeutic target in clinical trials. Here we found the expression levels of miR-155 was gradually down regulated and HIF-1α was upregulated in HS tissue and HS derived fibroblasts (HFs). And cell proliferation was inhibited when miR-155 was overexpressed or HIF-1α was silenced. Moreover, overexpression of miR-155 in HFs could reduce the expression of collagens in vitro and inhibit the collagen fibers arrangement in vivo, whereas miR-155 knockdown gave opposite results. Furthermore, we found that miR-155 directly targeted the HIF-1α, which could also independently inhibit the expression of collagens in vitro and obviously improved the appearance and architecture of the rabbit ear scar in vivo when it was silencing. Finally, we found that PI3K/AKT pathway was enrolled in these processes. Together, our results indicated that miR-155 was a critical regulator in the formation and development of hypertrophic scar and might be a potential molecular target for hypertrophic scar therapy.

Evaluation of nano hydrogel composite based on gelatin/HA/CS suffused with Asiatic acid/ZnO and CuO nanoparticles for second degree burns

In the present work, a hydrogel platform composed of biopolymer gelatin, and glycosaminoglycan's (Hyaluronic acid and Chondroitin sulfate) incorporated with Asiatic acid (a triterpenoid) and nanoparticles (Zinc oxide and Copper oxide) has been designed and developed to find out the efficacy of healing in second degree burn wounds in Wistar rats. The developed hydrogel composite has been characterized by physico-chemical methods such as; SEM, swelling, mechanical strength, degradation and drug release kinetics. Results showed that the morphology of composite scaffolds are porous with maximum water uptake capacity of 1068% and possessed tensile strength of ~0.196 MPa. Anti-microbial evaluation depicted increase in zone of inhibition with hydrogel containing gelatin + ZnO (5.3 ± 0.2 mm in E. coli and 4.9 ± 0.6 mm in S. aureus) and gelatin + CuO (4.8 ± 0.7 mm in E. coli, 3.8 ± 0.3 mm in S. aureus) in comparison to hydrogel composite scaffold. In-vitro cytocompatibility of developed hydrogel composite was assessed in terms of MTT and DNA quantification on L929 fibroblast cells. In-vivo studies for the composite scaffolds were evaluated on Wistar rats after second degree burn wounds were induced and studied for 28 days which showed the significant wound healing activity in comparison to the control (NeuSkin™ and Cotton guaze) in terms of DNA, total protein, hexosamine and hydroxyproline content. Histopathology studies showed the significant progress in re-epithelization, collagen fibers arrangement and angiogenesis in comparison to control. Additionally, a decrease of TNF-α and increase of MMP-2 expression on day 7 of animal experiment support healing. Furthermore, no toxicity was seen with the developed scaffolds suggesting their suitability to use as a wound dressing in second degree burns.

Simple preparation of hydroxyapatite nanostructures derived from fish scales

The nanostructured hydroxyapatite (HAp) formation in fish scales were investigated. Calcium and phosphate ions were effectively accumulated in the scales by the immersion processes. The HAp nanoparticles arranged in one direction in the internal fibrillary plate layers were observed, revealing the crystal growth along with the collagen fibers to resultantly form the porous structures. Thus, the arrangement of collagen fibers inside the scales effectively form the HAp nanostructures.

Histology and 3D Modeling of the Connective Tissue Skeleton in the Trunk of a Lamprey (Petromyzon marinus)

Agnathan lampreys play a key role in the reconstruction of the evolutionary history of vertebrates and, more specifically, in the analysis of the biomechanics underlying piscine undulatory locomotion. However, the morphology of the fibrous skeletal framework for their trunk musculature is still incompletely understood, mainly because of the complex spatial configuration of the segmentally arranged myosepta and muscle fibers within the myomeres. To contribute to a better understanding of how contractile muscular forces are transmitted via the fibrous skeletal framework of the trunk, the architecture and composition of the connective tissue structures (dermis, dorsal longitudinal ligament, hypodermis, myosepta, perimysial lamellae, notochord, fasciae) and their relationship to the muscle fibers of the myomeres were analyzed through histological techniques (in addition to MRI and microdissection described elsewhere) and 3D modeling based on a 3D reconstruction of serial histological sections treated with special stains (e.g., Movat Pentachrome, Ladewig Trichrome). These stains, however, did not differentiate tissue types as expected, probably because lamprey tissue fiber types differ biochemically from mammalian ones, but they discriminate a wide range of fiber types. As to the distribution of connective tissue fibers, the dermis comprises about 25 layers of helically arranged collagen fibers with the most superficial layers anchoring to the basement membrane of the epidermis and the deepest layers connecting to fibers of the hypodermis, which is separated by the pigment layer from the dermis. Radially arranged collagen fibers interconnect the basement membrane and hypodermis. Also within the hypodermis, the dorsal longitudinal ligament collects and interbraids collagen fibers from the dermis, hypodermis, and dorsal vertical septum, and, ultimately, the myosepta. The latter comprise tendon fibers connecting the roughly longitudinally oriented muscle fibers of adjacent myomeres and are traversed by thick collagen fiber bundles that run from the dermis to the central periaxial and perivisceral fasciae, as well as by thin reticulated fibers that support intramyoseptal nerves and blood vessels. The muscle blocks of the myomeres are separated by radially arranged perimysial lamellae running from the hypodermis to the periaxial and perivisceral fasciae. During undulations, contracting muscle fibers between the myosepta shorten and expand radially. This expansion is resisted by the radially arranged collagen fibers within the myosepta and perimysial lamellae. As a result, the internal pressure and, hence, the turgidity of the trunk is raised. A detailed understanding of the connective tissue fiber configuration in lampreys provides the necessary basis for building dynamic 3D models of the biomechanics involved in locomotion and other behaviors.Support or Funding InformationGrant‐In‐Aid of Research from Sigma Xi, the Scientific Research Society, to Bradley M. Wood; LSU Foundation support to Dominique G. HombergerThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Correlation between elastic parameters and collagen fibre features in breast lesions

To correlate elastic parameters with collagen fibre shape and arrangement features in breast lesions. Shear-wave elastography (SWE) was used to measure the stiffness of breast lesions in 54 patients before surgical removal. The value of stiffness was expressed as the mean and maximum elasticity (Emean and Emax). Lesions were sliced and stained with picric acid-sirius red to display the extracellular matrix (ECM) collagen fibre. The categories of the collagen fibres were based on the shape and arrangement features, i.e., category 0, wavy collagen fibres similar to normal breast tissue; category 1, taut parallel collagen fibres around tumour nests; category 2, straightened and aligned collagen fibres tending to be perpendicular to the tumour boundary; category 3, collagen fibre in a honeycomb arrangement. Bivariate correlation analysis was used to analyse the relationship between elastic parameters and collagen fibre category. For all 54 lesions, the correlation coefficient between Emean and category was 0.693 (p<0.001), and between Emax and category was 0.794 (p<0.001). For 36 malignant lesions, the correlation coefficient between Emean and category was 0.658 (p<0.001), and between Emax and category was 0.771 (p<0.001). Emean and Emax of breast lesions evaluated by SWE were positively correlated with ECM collagen fibre shape and arrangement category. Changes of ECM collagen fibre shape and arrangement may account for the stiffness variations of breast lesions.

Renaut bodies in the hind limb nerves of cattle with downer cow syndrome

Renaut bodies are loosely textured, whorled, cell-sparse structures that are located in the sub-perineurial area of peripheral nerves. Renaut bodies have been previously recognized in human beings and some animal species. Pathogenesis of the structures is not fully understood. In the present study, peripheral nerves of four adult Holstein-Friesian dairy cows affected with the downer cow syndrome were investigated histopathologically. The animals were culled 3 days (one case), 12 days (one case), or 11 days (two cases) after the onset of clinical signs indicative of motor dysfunction, such as hind limb paralysis, inability to rise, and recumbency. Histopathological lesions which had important clinical implications were recognized in the thigh muscles that presented extensive degeneration (necrosis) of muscle fibers in all four cases. In two cases, the sciatic nerve showed Wallerian degeneration of myelinated nerve fibers, while in two other cases, multiple Renaut bodies instead of these degenerative changes were found in the sub-perineurial area of almost all nerve bundles in either the left femoral nerve or left sciatic nerve. Renaut bodies were composed of loosely and circumferentially arranged collagen fibers and fibrocytes, giving rise to an appearance of circular or onion-like swirls. Pathogenesis of the Renaut bodies remained undetermined. There was no convincing histopathological evidence to suggest that such unique intraneural structures were implicated in the development of the cows’ clinical deficits.

Structure and collagen crimp patterns of functionally distinct equine tendons, revealed by quantitative polarised light microscopy (qPLM)

Structure-function relationships in tendons are directly influenced by the arrangement of collagen fibres. However, the details of such arrangements in functionally distinct tendons remain obscure. This study demonstrates the use of quantitative polarised light microscopy (qPLM) to identify structural differences in two major tendon compartments at the mesoscale: fascicles and interfascicular matrix (IFM). It contrasts functionally distinct positional and energy storing tendons, and considers changes with age. Of particular note, the technique facilitates the analysis of crimp parameters, in which cutting direction artefact can be accounted for and eliminated, enabling the first detailed analysis of crimp parameters across functionally distinct tendons.IFM shows lower birefringence (0.0013 ± 0.0001 [−]), as compared to fascicles (0.0044 ± 0.0005 [−]), indicating that the volume fraction of fibres must be substantially lower in the IFM. Interestingly, no evidence of distinct fibre directional dispersions between equine energy storing superficial digital flexor tendons (SDFTs) and positional common digital extensor tendons (CDETs) were noted, suggesting either more subtle structural differences between tendon types or changes focused in the non-collagenous components.By contrast, collagen crimp characteristics are strongly tendon type specific, indicating crimp specialisation is crucial in the respective mechanical function. SDFTs showed much finer crimp (21.1 ± 5.5 µm) than positional CDETs (135.4 ± 20.1 µm). Further, tendon crimp was finer in injured tendon, as compared to its healthy equivalents. Crimp angle differed strongly between tendon types as well, with average of 6.5 ± 1.4° in SDFTs and 13.1 ± 2.0° in CDETs, highlighting a substantially tighter crimp in the SDFT, likely contributing to its effective recoil capacity. Statement of SignificanceThis is the first study to quantify birefringence in fascicles and interfascicular matrix of functionally distinct energy storing and positional tendons. It adopts a novel method – quantitative polarised light microscopy (qPLM) to measure collagen crimp angle, avoiding artefacts related to the direction of histological sectioning, and provides the first direct comparison of crimp characteristics of functionally distinct tendons of various ages.A comparison of matched picrosirius red stained and unstained tendons sections identified non-homogenous staining effects, and leads us to recommend that only unstained sections are analysed in the quantitative manner.qPLM is successfully used to assess birefringence in soft tissue sections, offering a promising tool for investigating the structural arrangements of fibres in (soft) tissues and other composite materials.

Extracorporeal shock wave therapy with low-energy flux density inhibits hypertrophic scar formation in an animal model.

Hypertrophic scar is characterized by excessive deposits of collagen during skin wound healing, which could become a challenge to clinicians. This study assessed the effects of the extracorporeal shock wave therapy (ESWT) on hyper-trophic scar formation and the underlying gene regulation. A rabbit ear hypertrophic scar model was generated and randomly divided into three groups: L-ESWT group to receive L-ESWT (energy flux density of 0.1 mJ/mm2), H-ESWT (energy flux density of 0.2 mJ/mm2) and sham ESWT group (S-ESWT). Hypertrophic scar tissues were then collected and stained with hematoxylin and eosin (H&E) and Masson's trichrome staining, respectively, to assess scar elevation index (SEI), fibroblast density and collagen fiber arrangement. Expression of cell proliferation marker proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were assessed using RT-PCR and immunohistochemistry in hypertrophic scar tissues. H&E staining sections showed significant reduction of SEI and fibroblast density in both ESWT treatment groups compared to S-ESWT, but there was no dramatic difference between L-ESWT and H-ESWT groups. Masson's trichrome staining showed that collagen fibers were more slender and broader and oriented in parallel to skin surface after administration of ESWT compared to control tissues. At the gene level, PCNA-positive fibroblasts and α-SMA-positive myofibroblasts were significantly decreased after L-ESWT or H-ESWT compared to the controls. Furthermore, there was no significant difference in expression of PCNA mRNA between L-ESWT or H-ESWT and S-ESWT, whereas expression of α-SMA mRNA significantly decreased in L-ESWT compared to that of H-ESWT and S-ESWT (P=0.002 and P=0.030, respectively). In conclusion, L-ESWT could be effective on suppression of hypertrophic scar formation by inhibition of scar elevation index and fibroblast density as well as α-SMA expression in hypertrophic scar tissues of the rabbit model.

Nanofat Increases Dermis Thickness and Neovascularization in Photoaged Nude Mouse Skin.

To investigate the effects of nanofat injection into photoaged nude mouse skin on dermis thickness, neovascularization, and cell proliferation. Adipose-derived stem cells (ADSCs) and nanofat were prepared from human liposuction aspirates. The photoaged skin model was created using ultraviolet B (UVB) radiation onto BALB/c nude mice. A total of 24 mice were used in this study; 6 mice without treatment (natural aging) served as controls, while 18 mice were irradiated under the UVB lamp and treated with PBS (200μl per injection area), ADSCs (1×106/200μl ADSCs per injection area), or nanofat (200μl per injection area) on the dorsal skin. Four weeks after injection, skin specimens were collected. The skin texture of each group was evaluated by general observation. Histological analyses were performed to analyze skin structure, dermis thickness, collagen fiber arrangement, capillary density, and cell proliferation. Four weeks after injection, no obvious differences were observed between the PBS group, ADSCs group, and nanofat group by skin gross observation. From the histological analyses, the ADSCs group and the nanofat group showed obviously thicker dermis than the PBS group (P<0.05). More capillaries were observed in skin using anti-CD31 staining in the ADSCs and Nanofat groups than was observed in the PBS group (P<0.05). No significant differences in the average dermis proliferation index were observed between groups by anti-Ki-67 staining. However, an increased epidermal proliferation index was observed in the ADSCs and Nanofat groups, compared to that in the PBS group (P<0.05). Nanofat increased dermis thickness and neovascularization in photoaged skin. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .