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Topic:Collagen
Collagen is a structural protein found abundantly in the connective tissues of horses, including skin, tendons, ligaments, and cartilage. It contributes to the strength and elasticity of these tissues, playing a significant role in maintaining structural integrity. Collagen fibers are composed of amino acid chains, primarily glycine, proline, and hydroxyproline, which form a triple helix structure. In horses, collagen is involved in various physiological processes, including tissue repair and regeneration. Changes in collagen composition and structure can be associated with conditions such as joint disorders and tendon injuries. This page compiles peer-reviewed research studies and scholarly articles that explore the synthesis, function, and clinical implications of collagen in equine health.
Evaluation of collagenase activity, matrix metalloproteinase-8, and matrix metalloproteinase-13 in horses with chronic obstructive pulmonary disease. To determine collagenase activity and evaluate matrix metalloproteinase (MMP)-8 and MMP-13 in horses with chronic obstructive pulmonary disease (COPD). Methods: 12 horses with COPD and 12 healthy control horses. Methods: Collagenase activity was determined by use of an assay for degradation of type-I collagen. Western immunoblot analysis was used to identify interstitial collagenases MMP-8 and MMP-13 in tracheal epithelial lining fluid (TELF). Immunocytochemistry and in situ hybridization were used to determine cellular expression of these 2 collagenases in cells in bronchoalveolar lavage flui...
Use of an antineoepitope antibody for identification of type-II collagen degradation in equine articular cartilage. To develop an antibody that specifically recognizes collagenase-cleaved type-II collagen in equine articular cartilage. Methods: Cartilage specimens from horses euthanatized for problems unrelated to the musculoskeletal system. Methods: A peptide was synthesized representing the carboxy- (C-) terminus (neoepitope) of the equine type-II collagen fragment created by mammalian collagenases. This peptide was used to produce a polyclonal antibody, characterized by western analysis for reactivity to native and collagenase-cleaved equine collagens. The antibody was evaluated as an antineoepitope anti...
Changes in molecular expression of aggrecan and collagen types I, II, and X, insulin-like growth factor-I, and transforming growth factor-beta1 in articular cartilage obtained from horses with naturally acquired osteochondrosis. To determine molecular changes in the expression of insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) in horses with osteochondrosis, and to characterize expression of matrix aggrecan and collagen types I, II, and X in articular cartilage of affected joints. Methods: Articular cartilage from affected stifle or shoulder joints of 11 horses with naturally acquired osteochondrosis and corresponding joints of 11 clinically normal horses. Methods: Harvested specimens were snap frozen in liquid nitrogen, and total RNA was isolated. Specimens were fixed in 4% paraf...
Training affects the collagen framework of subchondral bone in foals. Subchondral bone provides structural support to the overlying articular cartilage and plays an important role in osteochondral diseases. There is growing insight that the mechanical features of bone are related to the biochemistry of the collagen network. In this study the effect of exercise on water, calcium and the collagen network (total collagen, lysyl-hydroxylation, hydroxylysylpyridinoline, and lysylpyridinoline crosslinks) of subchondral bone at two differently loaded sites (site 1: intermittently loaded; site 2: constantly loaded) is investigated in foals. Exercise influenced calcium c...
The application of an indenter system to measure structural properties of articular cartilage in the horse. Suitability of the instrument and correlation with biochemical data. A recently developed indenter system that aims at determination of local structural properties of the cartilage surface was evaluated for suitability in the horse. To this aim, maximum indenter force was measured of the articular surface and related to biochemical characteristics of the cartilage at different sites of the distal metacarpal bone (MC). Significant topographical variation exists in structural properties of the articular surface of the MC. The dorsal margin showed a significantly lower maximum indenter force than more centrally located areas, indicating an increased compliance und...
Differential regulation of gelatinases by transforming growth factor beta-1 in normal equine chondrocytes. Cartilage destruction in osteoarthritis (OA) is associated with increased levels of several matrix metalloproteinases (MMPs), including the gelatinases MMP-2 and MMP-9. While increases in some MMPs may be destructive, up-regulation of others may result from increases in normal tissue turnover. The production of MMP-2 and MMP-9 by the anabolic transforming growth factor beta-1 (TGF-beta1) in normal equine chondrocytes was investigated. Methods: Equine chondrocytes from clinically normal femoropatellar joints were maintained in alginate beads. After serum deprivation, cells were exposed to TGF-b...
Immunohistochemistry of the extracellular matrix of the normal equine lamina cribrosa. Purpose To use immunohistochemical techniques to identify and localize the structural macromolecules of the extracellular matrix (ECM) of the normal adult equine lamina cribrosa in order to make comparisons to the extracellular matrix of the lamina cribrosa of horses with glaucoma. METHODS: Normal eyes of five adult horses between 5 and 10 years of age were fixed in 10% neutral buffered formalin and embedded in paraffin. Polyclonal rabbit-derived antibodies against human elastin, laminin, fibrillin-1, and collagen types I, III and IV, and polyclonal goat-derived antibodies against collagen typ...
Effects of enrofloxacin and ciprofloxacin hydrochloride on canine and equine chondrocytes in culture. To study chondrotoxic effects of enrofloxacin (ENR) and ciprofloxacin hydrochloride (CFX) on canine and equine articular chondrocytes in culture and to compare the effects with that of cultivation in Mg2+-free medium. Methods: Chondrocytes from articular cartilage of 4- and 6 -month old dogs and 2- to 4- year-old horses. Methods: Chondrocytes were cultivated with 10, 40, 80, and 160 microg of CFX/ml, 10, 50, 100, and 150 microg of ENR/ml, or in Mg2+-free medium. A live-to-dead test was performed to test cytotoxic effects. Morphologic changes were evaluated by electron microscopy. An attachment...
Association of endometriosis in horses with differentiation of periglandular myofibroblasts and changes of extracellular matrix proteins. Periglandular fibrosis and cystic dilation of uterine glands are associated with equine endometriosis. The presence of extracellular matrix proteins (collagen type I, III and IV, laminin and fibronectin) in healthy and endometriotic specimens was demonstrated by immunohistochemistry. The distribution of collagen I, but not collagen III, was dependent on the stage of the oestrous cycle. The arrangement of collagen I and collagen III in endometriotic specimens was similar to that in normal endometrium. In periglandular fibrosis, collagen IV, laminin and fibronectin deposition outside the basemen...
Age-related changes in the testes of horses. Atrophy of seminiferous tubules and interstitial fibrosis are frequently observed in aged horses. Samples from 8 male Thoroughbreds, age 4-24 years, were subjected to histological, electron microscopical and immunohistochemical examination and statistical analysis. There were statistically significant increases in collagen fibres in the lamina propria of seminiferous tubules and testicular interstitium in 3 horses age 23 and 24 years compared with 5 horses age 4-20 years (P<0.001). Lamina propria surrounding atrophic tubules was thickened by an increase in collagen type IV and elastic fibre...
Serum markers of lamellar basement membrane degradation and lamellar histopathological changes in horses affected with laminitis. In order better to evaluate the extent to which degradation of the lamellar basement membrane (LBM) by matrix metalloproteinases (MMP) occurs in equine laminitis, we determined the concentration of type IV collagen and laminin in normal and laminitic horses, using specific immunoassays. Blood samples were obtained from both the jugular and the cephalic veins of horses (n = 10) before and after the induction of acute alimentary laminitis by carbohydrate overload. Jugular and cephalic venous blood samples were also obtained from horses affected with naturally occurring laminitis (n = 16) and non...
The influence of strenuous exercise on collagen characteristics of articular cartilage in Thoroughbreds age 2 years. In order to assess the influence of strenuous exercise on collagen characteristics of articular cartilage, the response of the collagen network was studied in seven 2-year-old Thoroughbreds subjected to strenuous exercise compared to 7 nontrained individuals. After 13 weeks, the animals were subjected to euthanasia, fetlock joints of the forelimbs were scored macroscopically after Indian Ink staining, and articular cartilage from different locations of the articular surface of the proximal first phalanx was sampled and analysed for water content, collagen content, hydroxylysine content and amo...
Influence of different exercise levels and age on the biochemical characteristics of immature equine articular cartilage. This study aimed to examine whether biochemical characteristics of juvenile articular cartilage are changing during the first year post partum and whether they can be influenced by exercise at young age. Water, glycosaminoglycan (GAG), DNA, total collagen, hydroxylysine and hydroxylysylpyridinoline (HP) content were measured in articular cartilage of 43 foals that were subdivided into 3 groups (n = 15, 14 and 14) which were subjected to different exercise regimens from one week after birth to age 5 months. At the age of 5 months all foals were weaned and 8 foals were selected randomly from eac...
Treatment of traumatically induced synovial sepsis in horses with gentamicin-impregnated collagen sponges. Eight horses with synovial sepsis induced by trauma were treated by arthroscopic/tenoscopic debridement and lavage followed by the implantation of a gentamicin-impregnated collagen sponge. Seven of them responded favourably and were sound six months after treatment. The other underwent a further surgical procedure and recovered. Gentamicin-impregnated collagen sponges appear to be a safe and useful adjunct in the treatment of septic joints and tendon sheaths, and have the advantage of being bioabsorbable.
Effect of transforming growth factor beta1 on chondrogenic differentiation of cultured equine mesenchymal stem cells. To determine the morphologic and phenotypic effects of transforming growth factor beta1 (TGFbeta1) on cultured equine mesenchymal stem cells (MSC) and articular chondrocytes. Methods: Bone marrow aspirates and articular cartilage samples from a 2-year-old and two 8-month-old horses. Methods: After initial isolation and culture, MSC and chondrocytes were cultured in Ham's F-12 medium supplemented with TGF-beta1 at a concentration of 0, 1, 5, or 10 ng/ml. Medium was exchanged on day 2, and cells were harvested on day 4. Medium was assayed for proteoglycan (PG) content. Total RNA was isolated fro...
Nodular diseases. The development of a nodule is a fairly common reaction pattern in the skin and subcutaneous tissues of the horse. In many such nodules, the inciting aetiologic agent or antigen is unknown, but in some equine cases there is significant evidence for insect bite origin. The pathogenesis of some equine nodular diseases appears to involve marked collagen degeneration which varies from hyalinization to lysis and can become mineralized. The exact role the lytic collagen has in the pathogenesis of these lesions is still unknown. Vascular changes may be present in some entities. Other nodules may be c...
Alterations in cartilage type-II procollagen and aggrecan contents in synovial fluid in equine osteochondrosis. The etiology and pathophysiology of osteochondrosis remain poorly understood because it is difficult to obtain material from lesions in the early stage of this disease and because there is no satisfactory experimental animal model. We wished to determine whether there are changes in articular cartilage turnover in equine osteochondrosis, which closely resembles the human disease, by assaying cartilage matrix molecules in synovial fluids. We used immunoassays that measure a keratan sulfate epitope and the epitope 846 on the cartilage proteoglycan aggrecan and the C-propeptide of cartilage type-...
Functional adaptation of equine articular cartilage: the formation of regional biochemical characteristics up to age one year. Biochemical heterogeneity of cartilage within a joint is well known in mature individuals. It has recently been reported that heterogeneity for proteoglycan content and chondrocyte metabolism in sheep develops postnatally under the influence of loading. No data exist on the collagen network in general or on the specific situation in the horse. The objective of this study was to investigate the alterations in equine articular cartilage biochemistry that occur from birth up to age one year, testing the hypothesis that the molecular composition of equine cartilage matrix is uniform at birth and b...
Equine retained placenta: technique for and tolerance to umbilical artery injections of collagenase. Under laboratory conditions and in clinical experiments, bacterial collagenase has proven to be effective in hydrolyzing placenta and detaching cotyledon from caruncle in the bovine species. Laboratory studies in which placental samples were incubated with collagenase have also demonstrated that collagenase is 3.7 times more effective in hydrolyzing equine placenta than bovine placenta. This led to the hypothesis that collagenase may be a potential treatment for mares with retained placenta. However, that collagenase may hydrolyze the uterine wall and perforate the uterus was a concern. It was...
Tissue strength and wound morphology of the equine linea alba after ventral median celiotomy. To evaluate the tensile strength and wound morphology of the equine linea alba at intervals over 6 months after ventral median celiotomy. Methods: Linea alba tensile strength and wound morphology were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Linea alba samples from 3 unoperated horses were used as controls. Methods: Eighteen adult horses, weighing 400 to 500 kg, 4 to 15 years old. Methods: Tensile strength and thickness of incised linea alba samples collected at 2, 4, 8, 16, and 24 weeks after ventral median celiotomy were compared with control linea alba samples. Additional sa...
Equine bullous pemphigoid IgG autoantibodies target linear epitopes in the NC16A ectodomain of collagen XVII (BP180, BPAG2). Bullous pemphigoid (BP) is an autoimmune subepithelial blistering dermatosis of humans, dogs, cats and pigs. It is characterized by skin-fixed and circulating IgG autoantibodies that target one or both BP antigens. An immunological homologue of BP in humans was diagnosed in two horses with cutaneous and mucosal ulcerations as well as microscopic subepithelial vesiculation. Immunological investigations revealed similar findings for both the horses. Direct immunofluorescence demonstrated the presence of IgG deposited linearly at the dermoepidermal junction in mucosal and skin biopsy specimens. I...
Staining abnormalities of dermal collagen in eosinophil- or neutrophil-rich inflammatory dermatoses of horses and cats as demonstrated with Masson’s trichrome stain. A retrospective study was performed on skin biopsy specimens from horses and cats having eosinophilic granulomas with 'collagen degeneration', eosinophilic skin diseases without 'collagen degeneration' and pyogranulomas without 'collagen degeneration'. Neither the appearance of collagen fibres nor the dominant polymorphonuclear cells, as seen in H & E-stained sections, were predictive of Masson's trichrome findings. Hence, a Masson's trichrome staining abnormality of collagen fibres was no more likely to be present in lesions with 'collagen degeneration' than in those lesions without 'coll...
Topographical mapping of biochemical properties of articular cartilage in the equine fetlock joint. The aim of this study was to evaluate topographical differences in the biochemical composition of the extracellular matrix of articular cartilage of the normal equine fetlock joint. Water content, DNA content, glycosaminoglycan (GAG) content and a number of characteristics of the collagen network (total collagen content, levels of hydroxylysine- (Hyl) and the crosslink hydroxylysylpyridinoline, (HP) of articular cartilage in the proximal 1st phalanx (P1), distal 3rd metacarpal bone (MC), and proximal sesamoid bones (PSB) were determined in the left and right fetlock joint of 6 mature horses (a...
Method for isolating preantral follicles from mare ovaries. The aims of this study were to evaluate the use of collagenase treatment to isolate preantral follicles from mare ovaries and to assess the effect of this treatment on follicular morphology. Intact mare ovaries were chopped into pieces, incubated individually with 1, 3 or 5 mg collagenase (type 1A) ml(-1) in a shaking waterbath at 37 degrees C for up to 2 h and passed through a series of stainless steel filters with pore size 50-300 microm to remove large clumps and stromal cells. The samples were prepared for histological analysis and sections were examined by light microscopy. Isolated folli...
Detection and effects on platelet function of anti-platelet antibody in mule foals with experimentally induced neonatal alloimmune thrombocytopenia. Horse mares carrying mule foals were immunized during the last trimester of pregnancy with whole acid-citrate-dextrose-anticoagulated donkey blood to experimentally induce neonatal alloimmune thrombocytopenia. Thrombocytopenia occurred in the neonatal mule foals born to immunized horse mares within 24 hours after ingestion of their dams' colostrum. Mule foals born to mares not immunized with donkey blood did not develop thrombocytopenia. These findings suggest that antibodies may have been directed against a donkey platelet antigen present in the mule foals but not present in their dams. The o...
Age-related changes to the molecular and cellular components of equine flexor tendons. Specific tendons show a high incidence of partial central core rupture which is preceded by degeneration. In the performance horse, the superficial digital flexor tendon (SDFT) is most often affected. We have described previously the molecular changes that are associated with degeneration in the central core region of the equine SDFT. The pathophysiological mechanism leading to change in synthetic activity of central zone cells in degenerated tendons is not known. In this study, we test the hypothesis that ageing results in matrix composition changes within the central zone of the SDFT. Extrac...
Influence of intermittent pressure, fluid flow, and mixing on the regenerative properties of articular chondrocytes. Equine articular chondrocytes, embedded within a polyglycolic acid nonwoven mesh, were cultured with various combinations of intermittent pressure, fluid flow, and mixing to examine the effects of different physical stimuli on neochondrogenesis from young cells. The cell/polymer constructs were cultured first in 125 ml spinner flasks for 1, 2, or 4 weeks and then in a perfusion system with intermittent pressure for a total of up to 6 weeks. Additional constructs were either cultured for all 6 weeks in the spinner flasks or for 1 week in spinners followed by 5 weeks in the perfusion system with...
Arthroscopic subchondral bone plate microfracture technique augments healing of large chondral defects in the radial carpal bone and medial femoral condyle of horses. To evaluate the effect of arthroscopic subchondral bone microfracture on healing of large chondral defects in horses. Methods: Short- (4 months) and long-term (12 months) in vivo experimental chondral defect model. Methods: 10 horses, aged 2 to 5 years. Methods: Each horse had a 1 cm2 full-thickness chondral defect created in both radial carpal bones and both medial femoral condyles. One carpus and one femoral condyle of each horse had the subchondral bone plate under the defect perforated using an orthopedic awl. All horses were exercised, five horses were evaluated after 4 months and five ho...
Immunopathology of pineal glands from horses with uveitis. Pinealitis accompanying uveitis is well established in laboratory models of experimental autoimmune uveoretinitis. In naturally occurring uveitis, pinealitis has been demonstrated in the pineal gland from a mare with active uveitis and is suspected in some human uveitides. We have evaluated pineal glands from horses with various stages of uveitis for signs of immunopathology accompanying spontaneous uveitis. Methods: Pineal glands from 10 horses with uveitis and from 13 horses without uveitis were evaluated for histochemical (H&E, collagen) and immunohistochemical (MHC class II antigen exp...
Morphological and histochemical analysis of a case of superficial digital flexor tendon injury in the horse. This report compares the morphology and the concentrations of glycos-aminoglycans (GAGs) in an injured superficial digital flexor tendon (SDFT) of a horse with those of a normal tendon. An injured 6-year-old male Thoroughbred exhibited heat and swelling around the SDFT of the right forelimb. On histopathological examination, exuberant granulation was observed in the affected tendon, with activated tenocytes, angiogenesis, haemorrhage, and infiltration of small numbers of leucocytes. The collagen fibres were loosely packed and irregularly arranged. The diameter of control collagen fibrils was 2...
