Topic:Equine model
The equine model refers to the use of horses as a biological model in scientific research to study various physiological and pathological processes. Horses are utilized in research due to their unique physiological characteristics, which can parallel certain aspects of human health and disease. This model is applied in studies ranging from musculoskeletal disorders and respiratory diseases to metabolic syndromes and reproductive health. Research involving equine models often investigates disease mechanisms, therapeutic interventions, and preventative strategies. This page gathers peer-reviewed research studies and scholarly articles that explore the application, benefits, and limitations of using horses as models in scientific research, providing insights into equine and comparative biomedical studies.
Production of horse foals via direct injection of roscovitine-treated donor cells and activation by injection of sperm extract. We evaluated the effects of different donor cell treatments and activation methods on production of blastocysts after equine nuclear transfer. Nuclear transfer was performed by direct injection of donor cells, using a piezo drill, and standard activation was by injection of sperm factor followed by culture with 6-dimethylaminopurine. There was no difference in blastocyst development between embryos produced with roscovitine-treated or confluent donor cells (3.6% for either treatment). Addition of injection of roscovitine or culture with cycloheximide at the time of activation did not affect bl...
A novel bioerodible deep scleral lamellar cyclosporine implant for uveitis. To determine the feasibility, safety, and effectiveness of an episcleral or deep scleral lamellar sustained release cyclosporine (CsA) device in a naturally occurring animal model of uveitis. Methods: A two-compartment perfusion chamber was used to assess in vitro human and equine scleral permeability of fluorescein, dexamethasone-fluorescein, or CsA. A biodegradable, matrix-reservoir CsA implant was designed, and release rates of CsA were determined in vitro. Tissue CsA levels were measured in eyes with the implant. Horses with equine recurrent uveitis (ERU) received episcleral or deep sclera...
The role of oxidative stress in an equine model of human asthma. Equine recurrent airway obstruction (RAO) is a naturally occurring respiratory disease in horses with many similarities to human asthma and, as a result, has been used as an animal model of this disease. Oxidative stress has been demonstrated to occur in a range of respiratory diseases in human beings including asthma. Quantitatively, horses have a greater non-enzymatic antioxidant capacity in the pulmonary epithelial lining fluid compared to human beings due to high ascorbic acid concentrations, which reflects their ability to synthesise ascorbic acid. Consequently, a greater oxidative load i...
Validation of an in vitro single-impact load model of the initiation of osteoarthritis-like changes in articular cartilage. The objective of this study was the development and characterization of an in vitro model of the initiation of traumatic osteoarthritis (OA). Articular cartilage was obtained from seven healthy horses and from four horses diagnosed with OA. Cartilage disks were subjected to a single-impact load (500 g from 25, 50, or 100 mm) using a simple drop-tower device and cultured in vitro for up to 20 days. Cartilage sections were examined histologically to observe surface damage and proteoglycan loss. Percentage cell death was determined using TUNEL, release of glycosaminoglycans (GAG) to the medium wa...
In vivo study on the short-term effect of radiofrequency energy on chondromalacic patellar cartilage and its correlation with calcified cartilage pathology in an equine model. Chondromalacia can cause joint pain and synovial effusion with the potential for developing into osteoarthritis. Thermal chondroplasty using radiofrequency energy (RFE) has been reported to be superior to mechanical debridement for treating chondromalacia. We compared short-term changes in biomechanical properties of articular cartilage after treatment with monopolar (mRFE) or bipolar RFE (bRFE) or mechanical debridement (MD) on experimentally created grade II chondromalacia patellae. Chondromalacia patellae was created arthroscopically in both patellae of 15 ponies. Ten months after surgery, ...
Vaccination against equine influenza: quid novi? Equine influenza virus is a leading cause of respiratory disease in the horse. Equine influenza vaccines containing inactivated virus were first developed in the 1960s. Despite their intensive use, equine influenza outbreaks still continue to occur and therefore new strategies of vaccination are necessary to improve vaccine efficacy. Numerous methods of vaccination have been evaluated and commercialised in the horse, the most recent being the cold-adapted influenza virus and poxvirus-based vaccines. As a large animal model, the horse is also a useful species in which to evaluate the potential ...
Protective effect of vaccination with recombinant proteins from Streptococcus equi subspecies equi in a strangles model in the mouse. A mouse model resembling Streptococcus equi subspecies equi infection in the horse, strangles, was used to assess the protective effect of vaccination with selected recombinant proteins from S. equi subsp. equi. After challenge the infection was monitored by weight loss and by nasal colonisation with S. equi subsp. equi. Vaccination with a collagen-binding protein (CNE) and a collagen-like protein (SclC) resulted in protective antibodies, whereas a novel fibronectin-binding protein (FNEB) did not. Co-administration of CNE with EAG, a poorly immunogenic alpha2-macroglobulin-, albumin- and immun...
Equine cloning: applications and outcomes. Cloning is one of several new assisted reproductive techniques being developed for clinical use in the equine industry. Potential uses of equine cloning include: (1) the preservation of genetics from individual animals that would otherwise not be able to reproduce, such as geldings; (2) the preservation of genetic material of endangered and/or exotic species, such as the Mongolian wild horse (Przewalski's horse); and (3) because of the companion animal role that horses fill for some individuals, it is likely that some horse owners will have individual animals cloned for emotional fulfillment. ...
Can a membrane oxygenator be a model for lung NO and CO transfer? To model lung nitric oxide (NO) and carbon monoxide (CO) uptake, a membrane oxygenator circuit was primed with horse blood flowing at 2.5 l/min. Its gas channel was ventilated with 5 parts/million NO, 0.02% CO, and 22% O2 at 5 l/min. NO diffusing capacity (Dno) and CO diffusing capacity (Dco) were calculated from inlet and outlet gas concentrations and flow rates: Dno = 13.45 ml.min(-1).Torr(-1) (SD 5.84) and Dco = 1.22 ml.min(-1).Torr(-1) (SD 0.3). Dno and Dco increased (P = 0.002) with blood volume/surface area. 1/Dno (P < 0.001) and 1/Dco (P < 0.001) increased with 1/Hb. Dno (P = 0.01...
Replication of West Nile virus in equine peripheral blood mononuclear cells. A cell model of primary monocytes and other mononuclear cells isolated from equine blood was used to study the kinetics of West Nile virus (WNV) replication in a natural host. West Nile virus has emerged on the North American continent as a significant cause of morbidity and mortality in a wide range of avian and mammalian species. While other flaviviruses are known to infect monocytes and lymphocytes, the ability of WNV to productively replicate in specific immune cells of peripheral blood has not been assessed. In this study, enriched populations of monocytes and lymphocytes as well as purif...
Role of endochondral ossification of articular cartilage and functional adaptation of the subchondral plate in the development of fatigue microcracking of joints. The mechanisms that regulate functional adaptation of the articular ends of long bones are poorly understood. However, endochondral ossification of articular cartilage and modeling/remodeling of the subchondral plate and epiphyseal trabeculae are important components of the adaptive response. We performed a histologic study of the distal end of the third metacarpal/metatarsal bone of Thoroughbreds after bones were bulk-stained in basic fuchsin and calcified sections were prepared. The Thoroughbred racehorse is a model of an extreme athlete which experiences particularly high cyclic strains in ...
Systemic concentrations of hormones during the development of follicular waves in mares and women: a comparative study. Changes in systemic concentrations of FSH, LH, oestradiol and progesterone during the ovulatory follicular wave were compared between 30 mares and 30 women. Based on a previous study, the emergence of the future ovulatory follicle was defined as occurring at 13.0 mm in mares and 6.0 mm in women, and deviation in diameter between the two largest follicles was expected to begin at 22.7 mm in mares and 10.3 mm in women. Mean FSH concentrations were high in mares during the luteal phase, resulting from statistically identified FSH surges occurring in individuals on different days and in different ...
Biochemical and biomechanical properties of lesion and adjacent articular cartilage after chondral defect repair in an equine model. Chondral defects may lead to degradative changes in the surrounding cartilage, predisposing patients to developing osteoarthritis. Objective: To quantify changes in the biomechanical and biochemical properties of the articular cartilage adjacent to chondral defects after experimental defect repair. Methods: Controlled laboratory study. Methods: Specimens were harvested from tissue within (lesion), immediately adjacent to, and at a distance from (remote area) a full-thickness cartilage defect 8 months after cartilage repair with genetically modified chondrocytes expressing insulin-like growth f...
Agonist-independent alteration in beta-adrenoceptor-G-protein-adenylate cyclase system in an equine model of recurrent airway obstruction. We examined the inhibitory sympathetic beta-adrenergic mechanisms in peripheral lung, bronchi and trachea of an equine model of recurrent airway obstruction (RAO), to support the hypothesis that the beta-adrenergic receptor dysfunction is not only restricted to cell surface receptor density but rather encompasses a mechanistic defect apart from the receptor, to the intracellular signaling components. The non-asthmatic lung possessed 3.2-fold more beta-adrenergic receptors than bronchi (496 +/- 19.4 vs. 155.1+/- 19.6 fmol/mg protein; P < 0.01) and 6.2-fold higher than in the trachea (79.8 +/...
Musculoskeletal modeling and dynamic simulation of the thoroughbred equine forelimb during stance phase of the gallop. Because thoroughbred racehorses have a high incidence of forelimb musculoskeletal injuries, a model was desired to screen potential risk factors for injuries. This paper describes the development of a musculoskeletal model of the thoroughbred forelimb and a dynamic simulation of the motion of the distal segments during the stance phase of high-speed (18 m/s) gallop. The musculoskeletal model is comprised of segment, joint, muscle-tendon, and ligament information. The dynamic simulation incorporates a proximal forward-driving force, a distal ground reaction force model, muscle activations, and ...
The effects of hormone replacement on the biomechanical properties of the uterosacral and round ligaments in the monkey model. The purpose of this study was to determine effects of ovariectomy (OVX) and conjugated equine estrogens plus medroxyprogesterone acetate (CEE/MPA), or ethinyl estradiol plus norethindrone acetate (EE/NA) on biomechanics of uterosacral (USL) and round (RL) ligaments in postmenopausal (PMP) monkeys. Methods: This was a randomized, triple blind, placebo-controlled study. OVX monkeys received 12 months no treatment (Pbo) (n = 19), CEE/MPA (n = 19), or EE/NA (n = 21). USL and RL step strains and stress-relaxation data were curve-fitted, giving strain-dependent tensile modulus (TM) from 0% to 30%. R...
Expression patterns of hedgehog signaling peptides in naturally acquired equine osteochondrosis. Hypertrophic differentiation and endochondral ossification of growth cartilage are regulated by a complex array of signaling peptides, including parathyroid hormone-related protein (PTH-rP), Indian hedgehog (Ihh), and bone morphogenetic proteins (BMPs). This study investigated the expression of Ihh, Patched1 and 2 (Ptc1, Ptc2), Smoothened (Smo), Gli1, and Gli3, in naturally acquired articular osteochondrosis, using an equine model. Cartilage was harvested from osteochondrosis (OC) affected femoropatellar or scapulohumeral joints from immature horses and normal control horses of similar age. Ih...
Effects of GnRH immunization in sexually mature pony stallions. Immunization against gonadotrophin releasing hormone (GnRH) was studied as an alternative for the commonly used surgical castration in stallions. Two GnRH vaccines comprising non-mineral oil adjuvants were evaluated for their potential to induce high antibody titers directed against GnRH and subsequent effects on reproductive characteristics. Twelve sexually mature male hemicastrated Shetland ponies were assigned to three groups. Group 1 and 2 were injected with 1mg peptide equivalent of G6k-GnRH-tandem-dimer conjugated to ovalbumin (OVA) in CoVaccine HT adjuvant (GnRH/CoVaccine) and in Carbop...
Immune response to vaccines based upon the VapA protein of the horse pathogen, Rhodococcus equi, in a murine model. Rhodococcus equi is a significant pathogen in foals predominantly causing a pyogranulomatous bronchopneumonia. Many vaccine candidates have been tested for the prevention of R. equi disease in foals. However, none of these have been developed for widespread commercial use. Previous studies have shown that a Th1 immune response is imperative for the protection of foals against R. equi disease. In this study a DNA and a protein vaccine based upon the well-characterised R. equi virulence-associated protein VapA were developed. The vaccines were tested in the BALB/c murine model and the results sh...
Influence of Ganoderma lucidum on blood biochemistry and immunocompetence in horses. The characteristic ingredients of Ganoderma lucidum, such as polysaccharides, triterpenoids, nucleic acids and small proteins, have been found and proved to have many special pharmacological properties. Mice and rats have been extensively used to investigate the effects of G. lucidum. Experiments with horses as an animal model for investigating the effects of G. lucidum have never been reported. The purpose of this investigation was to understand the influence of G. lucidum feeding on blood biochemistry and immunocompetence in horses. Complete blood count (CBC) and blood biochemistry were surv...
Sarcoplasmic masses in equine skeletal muscle. Sarcoplasmic masses in humans have been associated with various myopathies, although the significance remains elusive. Similar structures have also been observed in equine muscle. The aim of this study was to determine the frequency of such structures in normal and abnormal equine muscle, and to characterize these structures using histological, histochemical, immunohistochemical, ultrastructural, and morphometric analyses. The histological and histochemical appearance was similar to that of human sarcoplasmic masses with a central or subsarcolemmal distribution. Of interest was a predilection ...
Synovial fluid levels and serum pharmacokinetics in a large animal model following treatment with oral glucosamine at clinically relevant doses. To examine the concentration of glucosamine in the synovial fluid and its pharmacokinetics in serum in a large animal model following dosing with glucosamine HCl at clinically relevant levels. Methods: Eight adult female horses were studied. After an overnight fast, glucosamine HCl (20 mg/kg of body weight) was administered by either nasogastric (NG) intubation or intravenous (IV) injection. Blood samples were collected before dosing and at 5, 15, 30, 60, 120, 180, 240, 360, 480, and 720 minutes after dosing. Synovial fluid samples were collected from the radiocarpal joints 48 hours before dos...
Development of a model for inducing transient insulin resistance in the mare: preliminary implications regarding the estrous cycle. Peripheral insulin resistance is the failure of proper cellular glucose uptake in response to insulin. Insulin resistance and hyperinsulinemia are associated with several disease states in the horse and reproductive function disturbances in humans, including polycystic ovarian syndrome. To test the hypothesis that insulin resistance (IR) and hyperinsulinemia disrupt the estrous cycle in mares, two experiments were conducted to first develop a model to induce IR and to then examine the effect of this model on the duration of the estrous cycle. In Exp. 1, a hyperinsulinemic-euglycemic clamp (HEC...
In-vitro contraction of the equine aortic valve. The equine aortic valve is subject to non-inflammatory degenerative changes, associated with aortic valvular regurgitation (AR). This disease shares pathological and epidemiological features with AR in humans, and may serve as a useful model to study in-vitro functional responses associated with aging and disease. The study aim was to determine the contractile properties of the normal equine aortic valve. Methods: The contractile responses of equine aortic valves to angiotensin II, the thromboxane-mimetic U44069, endothelin-1, 5-hydroxytryptamine and the alpha-adrenoceptor agonists medetomidin...
Use of topical mitomycin C in myoplasty of the medial rectus muscle of rabbits. To possibly reduce postoperative adhesions that occur after ocular myoplasties, we investigated the topical effects of 0.04% mitomycin C on the repaired areas of the medial rectus muscle using an equine renal capsule preserved in 98% glycerin for reinforcement of the sutures. Twenty-four rabbits, divided into two groups of 12 animals each [untreated (control) and treated group (MMC)], were submitted to surgical rupture of the medial rectus muscle of one eye and repair of the defect 24 h later with sutures and an equine renal capsule. Post-operative prophylactic treatment of the two groups cons...
Proliferative aspects of airway smooth muscle. Increased airway smooth muscle (ASM) mass is perhaps the most important component of the airway wall remodeling process in asthma. Known mediators of ASM proliferation in cell culture models fall into 2 categories: those that activate receptors with intrinsic receptor tyrosine kinase activity and those that have their effects through receptors linked to heterotrimeric guanosine triphosphate-binding proteins. The major candidate signaling pathways activated by ASM mitogens are those dependent on extracellular signal-regulated kinase and phosphoinositide 3'-kinase. Increases in ASM mass may also...
Compensated overexpression of procollagens alpha 1(I) and alpha 1(III) following perilla mint ketone-induced acute pulmonary damage in horses. Interstitial lung disease with chronic fibrosis is a frequent cause of reduced performance in horses. The aim of this study was to establish a model of acute alveolar damage and interstitial lung disease in horses that could be used to monitor the histopathological lesions and changes in expression levels of genes relevant to pulmonary fibrosis. Six adult horses were given a single intravenous injection (6 mg per kg body weight) of perilla mint ketone (PMK). Transthoracic lung biopsy samples (1 x 0.2 x 0.2 cm) were collected before and after (days 1, 4, 8, 11, 15, 18, 22, 25 and 29) the admini...
[Combination immunization with EIAV Env protein expressed by recombinant baculovirus and recombinant vaccinia virus containing env gene]. To develop a novel vaccine candidate of Equine infectious anemia virus(EIAV). Methods: env genes of EIAV Chinese donkey leukocyte attenuated strain (EIAV DLV) and its parental virus strain (EIAV LN) were expressed using the BAC-To-BAC system, and Env proteins were confirmed by SDS-PAGE and Western blot. BALB/c mice were immunized with recombinant vaccinia viruses containing env genes of EIAV alone or boosted with Env proteins expressed by recombinant baculovirus. Both protective humoral and cellular immune responses were detected. Results: Recombinant baculovirus could express complete Env pro...
Tracing axons of peripheral nerves in rats: a potential technique to study the equine recurrent laryngeal nerve. To study the fascicular anatomy of peripheral nerves, three different groups of retrograde axonal tracers were evaluated: fluorophores, horseradish peroxidase conjugated to subunit B of cholera toxin (CT-HRP), and adeno-associated virus (AAV). The hindlimb nerves in rats served as a model to identify the most efficient tracer in regard to labeling axons within peripheral nerves. The rat's tibial and common peroneal nerves were injected with the different tracers and the sciatic nerve was subsequently examined for evidence of labeled axons. The CT-HRP clearly provided the best results in this r...
Comparative study of the dynamics of follicular waves in mares and women. Deviation in growth rates of the follicles of the ovulatory wave begins at the end of a common growth phase and is characterized by continued growth of the developing dominant follicle (F1) and regression of the largest subordinate follicle (F2). Follicle diameters during an interovulatory interval were compared between 30 mares and 30 women, using similar methods for collecting and analyzing data. Follicles were tracked and measured daily by ultrasonography. Diameter at follicle emergence (mares, 13 mm; women, 6 mm) and the required minimal attained diameter for assessment of follicles (mares...