Ultrastructure Of Collagen Fibers Research Articles

Effects of ultrasound and thermal treatment on the ultrastructure of collagen fibers from bovine tendon using atomic force microscopy

As the most important tenderness related protein in mammal, there are few studies on how the nanoscale morphology of collagen I in tissues is related to traditional meat processing. The ultrastructure and mechanical characteristics of collagen fibers in tendon with different treatments have been explored in this study. Collagen fibers in homogenate group and acetic acid group were treated with ultrasound and thermal treatment. The nanoscale morphology of collagen fiber in homogenate group became granular at 60 °C and gelatin was formed at 70 °C. The collagen fibers extracted from acetic acid are unstable and easier to break under the same processing parameters, when compared with homogenated collagen fibers in both ultrasound and thermal treatment. The results suggested that acetic acid can disassemble the salt bond and Schiff-base in collagen, and the collagen fibers became loose but the triple helix structure remained integrity.

Collagen fibrillar structures in vocal fold scarring and repair using stem cell therapy: a detailed histological, immunohistochemical and atomic force microscopy study.

Regenerative medicine opens new opportunities in the repair of cicatricial lesions of the vocal folds. Here, we present a thorough morphological study, with the focus on the collagen structures in the mucosa of the vocal folds, dedicated to the effects of stem cells on the vocal folds repair after cicatricial lesions. We used a conventional experimental model of a mature scar of the rabbit vocal folds, which was surgically excised with a simultaneous implantation of autologous bone marrow-derived mesenchymal stem cells (MSC) into the defect. The restoration of the vocal folds was studied 3 months postimplantation of stem cells and 6 months after the first surgery. The collagen structure assessment included histology, immunohistochemistry and atomic force microscopy (AFM) studies. According to the data of optical microscopy and AFM, as well as to immunohistochemical analysis, MSC implantation into the vocal fold defect leads not only to the general reduction of scarring, normal ratio of collagens type I and type III, but also to a more complete restoration of architecture and ultrastructure of collagen fibres in the mucosa, as compared to the control. The collagen structures in the scar tissue in the vocal folds with implanted MSC are more similar to those in the normal mucosa of the vocal folds than to those of the untreated scars. AFM has proven to be an instrumental technique in the assessment of the ultrastructure restoration in such studies. LAY DESCRIPTION: Regenerative medicine opens new opportunities in the repair of the vocal fold scars. Because collagen is a main component in the vocal fold mucosa responsible for the scar formation and repair, we focus on the collagen structures in the mucosa of the vocal folds, using a thorough morphological study based on histology and atomic force microscopy (AFM). Atomic force microscopy is a scanning microscopic technique which allows revealing the internal structure of a tissue with a resolution up to nanometres. We used a conventional experimental model of a mature scar of the rabbit vocal folds, surgically excised and treated with a mesenchymal stem cells transplant. Our morphological study, primarily AFM, explicitly shows that the collagen structures in the scarred vocal folds almost completely restore after the stem cell treatment. Thus, the modern microscopic methods, and especially AFM are instrumental tools for monitoring the repair of the vocal folds scars.

Ultrastructure of collagen fibers and distribution of extracellular matrix in the temporomandibular disk of the human fetus and adult.

We quantitatively examined the distribution of these differences in extracellular matrices (collagen types I, III, and fibronectin) and elastic fibers under confocal laser scanning microscopy and electron scanning microscopy in terms of their contribution to the mechanics of the TMJ during development and in adults. Elastic fibers were found in the anterior and posterior bands in adults aged 40 years, and a few elastic fibers in the anterior band of the disk in adults aged 80 to 90 years. The extracellular matrix contents of the TMJ disk are shown in various detected levels in the anterior, intermediate, posterior bands of TMJ disk. During development, collagen fibers are arranged in a complex fashion from 28 weeks' gestation. These ultrastructures of the embryonic TMJ are resembled to that of adults aged the 40s, however the difference in extracellular matrix distribution found in embryonic stages and adults. They might reflect the differences in function between mastication and sucking or the changes in shape and form as results of functional disorders of the TMJ.

Persistence of birefringence and specific collagen cross-links in dentine of teeth of the ‘Nuraghi’ population living in SardiniaBC 1500–1200

Well preserved bones of the Nuraghi population, discovered in 1980, are deposited in the Department of Biomedical Sciences, Division of Human Anatomy of the University of Sassari, in Sardinia, Italy. The Giant Tomb belongs to the megalithic monuments constructed in the period BC 1500–1200. The origin, history and the fate of Nuraghi population is not well known. Many cone-shaped fortresses are found in Sicily and megalithic monuments for burial purposes were built in their proximity. Due to the good macroscopic preservation of the mineralized parts of the Nuraghi skeletons we decided to compare the histological and biochemical structure of the recovered Nuraghi teeth with contemporary ones. Crown dentine of four Nuraghi molar and four premolar teeth were analysed and compared with contemporary molars and premolars removed for orthodontic reasons from 17–40-year-old patients in the Dental School, University of North Carolina at Chapel Hill USA. Evaluation of the collagen cross-links of dentine collagen was performed using a HPLC technique to analyze for hydrolysates. Nonreducible, stable cross-links pyridinoline and its lysyl analogue were quantified by fluorescence (excitation 330 nm, emission 390 nm). The concentration of reducible, labile cross-links referred to as DHLNL and HLNL (dehydro-dihydroxylisinorleucine) were identified and calculated by chromatography after the application of NaB3H4 with integration of respective peaks and converting the numbers into a residue per mole of collagen basis. The ultrastructure of collagen was estimated by its persistent birefringence in polarized light after staining with Picrosirus Red. It was found that dentine collagen of Nuraghi teeth resisted environmental factors sufficiently well to preserve the molecular ultrastructure of collagen fibres, proved by their birefringence and by the preservation of some of the stable and reducible collagen cross-links, characteristic for skeletal tissues. © 1998 John Wiley & Sons, Ltd.

Collagen and glycosaminoglycans of Wharton's jelly.

In this study, we report quantity, solubility and molecular polymorphism of collagen, proportional relationships between various types of collagen, ultrastructure of collagen fibres, the amounts of various glycosaminoglycans (GAGs) and proportional relationships between them in Wharton's jelly of normal umbilical cords. We compare the extracellular matrix components in Wharton's jelly with those in the umbilical cord artery. Collagen of the Wharton's jelly demonstrates some specific features. It is very insoluble in neutral salt and in a slightly acidic solution and appears to be resistant to the action of depolymerizing agent (EDTA-Na2). Only 50% of total collagen may be solubilized by pepsin digestion and fractionated by differential salt precipitation. Four collagen fractions were obtained. Three of them were identified by polyacrylamide gel electrophoresis as type I, type III, and type V collagen and proportional relationship between them was calculated. Hyaluronic acid is the most abundant component of GAGs contained in Wharton's jelly. The amounts of sulphated GAGs-keratan sulphate, heparan sulphate, chondroitin-4-sulphate, chondroitin-6-sulphate, dermatan sulphate and heparin-are distinctly lower. Each of them constitutes only a few percent of total GAGs.

Three-dimensional ultrastructure of collagen fibers in repaired palatal wounds of rats

Three-dimensional ultrastructure of collagen fibers in repaired palatal wounds of rats

Ultrastructure of collagen fibers in the outer membrane of recurrent chronic subdural hematoma.

The three-dimensional structure of the collagen fibers in the outer membrane of recurrent chronic subdural hematoma was studied by scanning electron microscopy (SEM). Specimens obtained at surgery were treated with NaOH at room temperature to digest away all cellular components and expose the collagen fibers. SEM observation of the dural side of the outer membrane showed the collagen fibers were woven into a compact feltwork with a dense arrangement. The fiber bundles had a honeycomb structure framed by the collagen fibers. Observation of the hematoma side found the collagen bundles had a sparse wavy appearance. The arrangement of the collagen fibers on the dural side is different from that on the hematoma side. The thick outer membrane may be formed by granulation resulting from inflammatory reaction. Collagen fibrillar networks are not fragile, and may reinforce the outer membrane of the recurrent hematoma.

Structural abnormalities in the mitis form (type-II) of Ehlers-Danlos syndrome.

ABSTRACTThe ultrastructure of collagen fibers in the dermis of Ehlers‐Danlos syndrome (EDS) has been described in several previous reports. However, discussions of the ultrastructural changes in EDS‐Type II have been infrequent and brief. The behavior of alterative degeneration remains unclear, although there has been one previous report each on EDS‐Type I, Type VI, and Type VII (1, 3, 6). Our ultrastructural studies of EDS‐Type II revealed that bundles of collagen fibers were slightly thinner than in normal human skin, as were the individual collagen fibers also. Two or three serrated collagen fibers (up to 188 nm) were seen within the collagen bundle. The width of these serrated fibers was clearly less than in EDS‐Type I, and these fibers were less frequent than in the severe clinical form of EDS. It could be useful to be able to classify the subtypes of the EDS by structural pattern as well as by clinical appearance.

Relationship of the ultrastructure and mechanical properties in tendinous collagen, a highly ordered macromolecular composite

A relationship has been found between the stress and deformation in tendon and, from an analysis of the data obtained, it was established that there is a major stress-bearing fiber, the diameter of which increases with increasing age of the animal. The relationship of the results obtained with the structure and properties of tendon as well as with the aging process is stressed. Models of the ultrastructure of collagen fibers in rat tail tendon or in other soft connective tissue were prepared by sealing rigid fibers in a considerably softer elastic matrix. Loss of fiber resistance was achieved by contraction of this matrix. These synthetic composite systems exactly reflect a number of the features of the collagen ultra-structure. Models were also used for studying stresses in the matrix about the fibers as this necessary information could not be obtained by a direct study of the biological tissues. Examination of the reaction between tropocollagen and the connective tissue polysaccharides in the process of collagen fiber formation shows that a mechanism exists through which the fibers may lose their resistance also in vivo.

An approach to experimental scleroderma, using urinary glycosaminoglycans from patients with systemic scleroderma

As a result of intraperitoneal injections in mice of crude glycosaminoglycans obtained from the urine of patients with systemic scleroderma, a fibrotic process similar to the intial changes of human scleroderma was frequently observed, especially in the skin and esophagus when the glycosaminoglycans contained a probable variant of heparan sulfate. Furthermore, the scleroderma-like change was also observed, to some extent, in the ultrastructure of collagen fibers and glycosaminoglycans of the skin.