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Topic:Biochemistry
The study of biochemistry in horses encompasses the chemical processes and substances that occur within equine organisms. This field investigates the molecular interactions and pathways that are fundamental to horse physiology, including metabolism, enzyme activity, and genetic expression. Key areas of interest include the examination of metabolic disorders, nutrient absorption, and the biochemical basis of muscle function and energy production. Researchers utilize biochemical analysis to understand health and disease mechanisms in horses, contributing to the development of diagnostic tools and therapeutic strategies. This page gathers peer-reviewed studies and scholarly articles that explore various biochemical processes and their implications for equine health and performance.
Biochemical markers of bone turnover during pregnancy in horses: a longitudinal study. The effect of pregnancy on bone metabolism was investigated in healthy mares. Venous blood samples were collected 7 times from 19 multiparous mares starting at 20-weeks pre-parturition, continuing 6 times in 4-week intervals, including the week of parturition and one week after parturition. Serum concentrations of osteocalcin (OC) and carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I) were determined. Measurement cycles and age had a significant (p < 0.01) influence on OC and CTX-I values. Pregnancy influenced bone metabolism with peak bone formation and resorption values...
Distribution of purinergic P2X receptors in the equine digit, cervical spinal cord and dorsal root ganglia. Purinergic pathways are considered important in pain transmission, and P2X receptors are a key part of this system which has received little attention in the horse. The aim of this study was to identify and characterise the distribution of P2X receptor subtypes in the equine digit and associated vasculature and nervous tissue, including peripheral nerves, dorsal root ganglia and cervical spinal cord, using PCR, Western blot analysis and immunohistochemistry. mRNA signal for most of the tested P2X receptor subunits (P2X1-5, 7) was detected in all sampled equine tissues, whereas P2X6 receptor su...
Impact of laminitis on the canonical Wnt signaling pathway in basal epithelial cells of the equine digital laminae. The digital laminae is a two layer tissue that attaches the distal phalanx to the inner hoof wall, thus suspending the horse's axial skeleton in the hoof capsule. This tissue fails at the epidermal:dermal junction in laminitic horses, causing crippling disease. Basal epithelial cells line the laminar epidermal:dermal junction, undergo physiological change in laminitic horses, and lose versican gene expression. Versican gene expression is purportedly under control of the canonical Wnt signaling pathway and is a trigger for mesenchymal-to-epithelial transition; thus, its repression in laminar ep...
Selection of developmentally competent immature equine oocytes with brilliant cresyl blue stain prior to in vitro maturation with equine growth hormone. Immature oocytes synthesize a variety of proteins that include the enzyme glucose-6-phosphate dehydrogenase (G6PDH). Brilliant cresyl blue (BCB) is a vital blue dye that assesses intracellular activity of G6PDH, an indirect measure of oocyte maturation. The objective was to evaluate the BCB test as a criterion to assess developmental competence of equine oocytes and to determine if equine growth hormone (eGH) enhanced in vitro maturation (IVM) of equine oocyte. Cumulus-oocytes complexes (COCs) were recovered by aspirating follicles 0.05). Maturation was not affected significantly by BCB class...
Extracellular ATP signaling in equine digital blood vessels. The functional distribution of ATP-activated P2 receptors is well characterized for many blood vessels, but not in the equine digital vasculature, which is a superficial vascular bed that displays thermoregulatory functions and has been implicated in ischemia-reperfusion injuries of the hoof. Isolated equine digital arteries (EDA) and veins (EDV) were submitted to isometric tension studies, whereby electric field stimulation (EFS) and concentration-response curves to exogenously applied agonists were constructed under low tone conditions. Additionally, immunofluorescent localization of P2X and...
Metabolic studies of formestane in horses. Formestane (4-hydroxyandrost-4-ene-3,17-dione) is an irreversible steroidal aromatase inhibitor with reported abuse in human sports. In 2011, our laboratory identified the presence of formestane in a horse urine sample from an overseas jurisdiction. This was the first reported case of formestane in a racehorse. The metabolism of formestane in humans has been reported previously; however, little is known about its metabolic fate in horses. This paper describes the in vitro and in vivo metabolic studies of formestane in horses, with the objective of identifying the target metabolite with the lon...
Scaffold effects on osteogenic differentiation of equine mesenchymal stem cells: an in vitro comparative study. The in vitro viability, osteogenic differentiation, and mineralization of four different equine mesenchymal stem cells (MSCs) from bone marrow, periosteum, muscle, and adipose tissue are compared, when they are cultured with different collagen-based scaffolds or with fibrin glue. The results indicate that bone marrow cells are the best source of MSCs for osteogenic differentiation, and that an electrochemically aggregated collagen gives the highest cell viability and best osteogenic differentiation among the four kinds of scaffolds studied.
Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry. In recent years, there has been an ongoing focus for both human and equine doping control laboratories on developing detection methods to control the misuse of peptide therapeutics. Immunoaffinity purification is a common extraction method to isolate peptides from biological matrices and obtain sufficient detectability in subsequent instrumental analysis. However, monoclonal or polyclonal antibodies for immunoaffinity purification may not be commercially available, and even if available, such antibodies are usually very costly. In our study, a simple mixed-mode anion exchange solid-phase extra...
Pharmacokinetics and pharmacodynamic effects of tolazoline following intravenous administration to horses. Tolazoline is an α2-adrenergic receptor antagonist, used in veterinary medicine to antagonize the central nervous system depressant and cardiovascular effects of α2 receptor agonists. The pharmacokinetics and pharmacodynamic effects of tolazoline when administered subsequent to detomidine in the horse were recently reported, although the reversal of the sedative and cardiovascular effects following detomidine may not be complete. The current study therefore investigated the pharmacokinetics and pharmacodynamic effects of tolazoline when administered as a sole agent. Nine healthy adult horses...
Preclinical assessment of a polyspecific antivenom against the venoms of Cerrophidion sasai, Porthidium nasutum and Porthidium ophryomegas: Insights from combined antivenomics and neutralization assays. A polyspecific antivenom is used in Central America for the treatment of envenomings by viperid snakes. This antivenom is generated in horses hyperimmunized with a mixture of venoms from Bothrops asper, Crotalus simus and Lachesis stenophrys. The present study analyzed the ability of this antivenom to neutralize the venoms of three Central American viperid species of the 'Porthidium group', i.e. Porthidium nasutum, Porthidium ophryomegas and Cerrophidion sasai, formerly classified as Cerrophidion godmani. In addition, the immunorecognition of the components of these venoms was assessed by immu...
Expression of scleraxis and tenascin C in equine adipose and umbilical cord blood derived stem cells is dependent upon substrata and FGF supplementation. Recovery from tendon injury is based on long periods of rest, which results in sub-optimal repair, often replacing tendon with fibrocartilage scar tissue. Recently, the use of stem cells in equine tendon repair has been attempted with variable success. The objective of this work was to determine the expression of scleraxis (scx) and tenascin C (TnC), two markers of tenocytes, in adipose (AdMSC) and umbilical cord blood (UCB) stem cells during culture on various substrata and in response to fibroblast growth factor (FGF) treatment. Equine UCB and AdMSC were cultured on gelatin-coated plasticwar...
Expression of anti-Müllerian hormone, CDKN1B, connexin 43, androgen receptor and steroidogenic enzymes in the equine cryptorchid testis. Cryptorchidism affects 2-8% of male horses and the affected testis undergoes a disruption of normal spermatogenesis. The underlying molecular changes are poorly understood in the cryptorchid equine testis. Objective: Compare the expression of anti-Müllerian hormone (AMH), anti-Müllerian hormone receptor (AMHR2), androgen receptor (AR), cyclin kinase inhibitor (CDKN1B), connexin 43 (Cx43), 3β hydroxysteroid dehydrogenase/Δ(5) -Δ(4) - isomerase (3βHSD), P450c17 hydroxylase/lyase (P450c17) and cytochrome P450 aromatase (P450arom) in the undescended testis of cryptorchid stallions with that ...
Plasma cortisol and faecal cortisol metabolites concentrations in stereotypic and non-stereotypic horses: do stereotypic horses cope better with poor environmental conditions? Stereotypic behaviours, i.e. repetitive behaviours induced by frustration, repeated attempts to cope and/or brain dysfunction, are intriguing as they occur in a variety of domestic and captive species without any clear adaptive function. Among the different hypotheses, the coping hypothesis predicts that stereotypic behaviours provide a way for animals in unfavourable environmental conditions to adjust. As such, they are expected to have a lower physiological stress level (glucocorticoids) than non-stereotypic animals. Attempts to link stereotypic behaviours with glucocorticoids however have y...
Short- and long-term effect of oral administration of micellized natural vitamin E (D-α-tocopherol) on oxidative status in race horses under intense training. This study tested the effect of micellized vitamin E (D-α-tocopherol; 1,400 IU/d) administered 12 and 1 h orally before training for 1 d (ST-VitE) or 8 d (LT-VitE) compared with an unsupplemented control (CONTROL) on plasma α-tocopherol, thiobarbithuric acid-reactive substances (TBARS), total glutathione (GSHt), and trolox equivalent antioxidant capacity (TEAC) in 10 race horses. Different sampling times [immediately before training (BEF) and after intense training (END) or 8 h after recovery (+8h)] were investigated. Plasma α-tocopherol concentration was greater in the ST-VitE group than t...
The welfare of young Polish Konik horses subjected to agricultural workload. Every year a new group of young Polish Konik colts are separated from the forest herds to be trained in the stable breeding system. The aim of this study was to evaluate how the young Polish Konik horses who had been born in a forest reserve adapt to and tolerate draft work. Two groups of 6 horses each were studied: (a) 3- to 4-year-old colts and (b) 7- to 13-year-old stallions. An effort response was estimated by heart rate (HR) registration and biochemical analysis of hematocrit; blood lactic acid (LA) level; and plasma concentration of glucose, triacylglycerols, uric acid, total protein, an...
Serum biochemical reference intervals for the Polish Konik horse (Equus cabalus gmelini Ant.). Establishment of reference intervals (RI) for serum biochemical analytes is important for monitoring the health of different breeds of horses. Objective: The aim of this study was to measure and report RI for serum biochemical analytes of the Polish Konik horse. Methods: Blood samples were collected from 74 clinically healthy Polish Konik horses living under controlled natural conditions. These were adult primitive horses, aged 3-15 years, including 28 males (21 stallions, 7 geldings) and 46 mares. Serum analytes were measured and analyzed using a commercial automated analyzer. Results: The fo...
Capacity for colonization and degradation of horse manure and wheat-straw-based compost by different strains of Agaricus subrufescens during the first two weeks of cultivation. The potential of Agaricus subrufescens strains to colonize and transform horse manure and wheat-straw-based mushroom compost under the physico-chemical conditions typically used for Agaricus bisporus was assessed. Lignocellulolytic activities, H2O2 production and substrate transformation (assessed via CP/MAS NMR of (13)C) for certain A. subrufescens strains were similar or even greater than those obtained for an A. bisporus strain used as control. Moreover, the functional diversity of the microbial communities of the substrate was not altered by the growth of A. subrufescens after 2weeks. Thes...
Effect of myeloperoxidase and anoxia/reoxygenation on mitochondrial respiratory function of cultured primary equine skeletal myoblasts. Horses are particularly sensitive to excessive inflammatory reaction where myeloperoxidase, a marker of inflammation, may contribute to mitochondrial dysfunctions. This study investigated the interaction between myeloperoxidase and cultured primary equine skeletal myoblasts, particularly its effect on mitochondrial respiration combined or not with anoxia followed by reoxygenation (AR). We showed that active myeloperoxidase entered into the cells, interacted with mitochondria and decreased routine and maximal respirations. When combined with AR, myeloperoxidase caused a further decrease of thes...
Influence of corticosteroids on interleukin-1β-stimulated equine chondrocyte gene expression. To compare the effects of triamcinolone acetonide (TA) and methylprednisolone acetate (MPA) on expression of selected chondrocyte genes in recombinant equine interleukin-1β (reIL-1β) stimulated articular cartilage explants. Methods: In vitro experiment. Methods: Horses (n = 6). Methods: Articular cartilage explants from 2- to 3- year-old horses were exposed to reIL-1β in the presence and absence of TA and MPA at 10(-7) and 10(-6) M. Resting levels of mRNA of anabolic and catabolic genes of chondrocyte origin were quantified using qPCR after 6- and 12-hour incubations. Genes of interest incl...
[Isolation, identification and enzyme characterization of a thermophilic cellulolytic anaerobic bacterium]. To identify a thermophilic bacterium from horse manure to degrade cellulose efficiently, and to enrich microbial resources producing cellulolytic ethanol by co-culturing with thermophilic ethanol producing bacterium. Methods: We used Hungate anaerobic technique to isolate a strain named as HCp from horse manure mixed culture; its phylogeny was identified through 16S rDNA sequencing. Enzymatic assays were determined using DNS method. Results: The isolated HCp cells were straight with rods size of(0.35-0.50) microm x (2.42-6.40) microm, in the form of single or paring. This strain belongs to a s...
Identification of protoxins and a microbial basis for red maple (Acer rubrum) toxicosis in equines. The leaves of Acer rubrum (red maple), especially when wilted in the fall, cause severe oxidative damage to equine erythrocytes, leading to potentially fatal methemoglobinemia and hemolytic anemia. Gallic acid and tannins from A. rubrum leaves have been implicated as the toxic compounds responsible for red maple toxicosis, but the mechanism of action and toxic principle(s) have not been elucidated to date. In order to investigate further how red maple toxicosis occurs, aqueous solutions of gallic acid, tannic acid, and ground dried A. rubrum leaves were incubated with contents of equine ileum,...
Treatment of a bone defect consequent to the removal of a periapical cyst with equine bone and equine membranes: clinical and histological outcome. While deproteinized bovine bone and bovine membranes have been well studied and can yield good results when used to treat bone defects and peri-implant dehiscences, enzymatically deantigenated equine bone and equine membranes have emerged as possible alternative biomaterials. The objective of this study was the clinical and histological assessment of such materials: equine bone granules, an equine collagen membrane and an equine pericardium membrane. Methods: Enzymatically deantigenated equine bone and an equine collagen membrane were used to restore a bone defect caused by the removal of a bo...
PI3K and MAPKs regulate neutrophil migration toward the airways in heaves. Neutrophils accumulate in the airways of horses with heaves. They likely play an important role in the disease pathogenesis. Understanding the pathways regulating their migration may help identifying new therapeutic targets. Objective: MAPK and PI3K pathways are involved in neutrophil migration toward the airway lumen in heaves. Methods: Twelve heaves-affected horses and 4 healthy horses. Methods: Migratory activity of bronchoalveolar lavage fluids (BALF) from horses with heaves and healthy horses was compared by means of a Boyden chamber. Involvement of MAPK and PI3K pathways in neutrophil mi...
Biochemical evaluation of equine articular cartilage through imaging. The use of molecular imaging of cartilage is the next vital step in understanding, treating, and training the equine athlete. Because of the logistics of precontrast and postcontrast medium imaging, the clinical usefulness of the examination has come into question. With the large number of horses undergoing high-field magnetic resonance imaging, the use of contrast medium administration and T1 mapping or T2 imaging precontrast and postcontrast medium administration may add a limited amount of time to the scan and has the potential to provide more detailed information about the chemical composi...
Association of oxidative stress with motor neuron disease in horses. To investigate the influence of oxidative stress in terms of antioxidant capacity and lipid peroxidation on the probability of motor neuron disease (MND) in horses. Methods: 88 horses with MND (cases) and 49 controls. Methods: Blood samples were collected from all horses enrolled, and RBCs and plasma were harvested. Activity of the enzyme erythrocytic superoxide dismutase 1 (SOD1) was determined in the RBCs. Plasma concentrations of α-tocopherols and β-carotenes and activity of glutathione peroxidase were also evaluated. Degree of lipid peroxidation was measured by determining plasma concent...
True blue: S-opsin is widely expressed in different animal species. Colour vision in animals is an interesting, fascinating subject. In this study, we examined a wide variety of species for expression of S-opsin (blue sensitive) and M-/L-opsin (green-red sensitive) in retinal cones using two novel monoclonal antibodies specific for peptides from human opsins. Mouse, rat and hare did not express one of the investigated epitopes, but we could clearly prove existence of cones through peanut agglutinin labelling. Retinas of guinea pig, dog, wolf, marten, cat, roe deer, pig and horse were positive for S-opsin, but not for M-/L-opsin. Nevertheless all these species ...
Seasonal pasture myopathy/atypical myopathy in North America associated with ingestion of hypoglycin A within seeds of the box elder tree. We hypothesised that seasonal pasture myopathy (SPM), which closely resembles atypical myopathy (AM), was caused by ingestion of a seed-bearing plant abundant in autumn pastures. Objective: To identify a common seed-bearing plant among autumn pastures of horses with SPM, and to determine whether the toxic amino acid hypoglycin A was present in the seeds and whether hypoglycin metabolites were present in SPM horse serum or urine. Methods: Twelve SPM cases, 11 SPM pastures and 23 control farms were visited to identify a plant common to all SPM farms in autumn. A common seed was analysed for amin...
Inflamm-aging and arachadonic acid metabolite differences with stage of tendon disease. The contribution of inflammation to the pathogenesis of tendinopathy and high prevalence of re-injury is not well established, although recent evidence suggests involvement of prostaglandins. We investigated the roles of prostaglandins and inflammation-resolving mediators in naturally occurring equine tendon injury with disease stage and age. Levels of prostaglandins E(2) (PGE(2)), F(2α) (PGF(2α)), lipoxin A(4) (LXA(4)) and its receptor FPR2/ALX were analysed in extracts of normal, sub-acute and chronic injured tendons. To assess whether potential changes were associated with altered PGE(2) ...
O(6)-methylguanine-DNA methyltransferase in equine sarcoids: molecular and epigenetic analysis. Bovine papillomaviruses (BPVs) types 1 and 2 are the only known papillomaviruses able to jump the species. In fact, BPVs 1/2 induce neoplasia in their natural bovine host but infection is also associated to neoplastic skin lesions in equids termed sarcoids. The equine sarcoid is considered to be the most common equine cutaneous tumour worldwide for which no effective therapy is available. Very little is known about the molecular mechanisms underlying tumourigenesis, although genes contributing to sarcoid development have been identified. Several studies associate the development of cancer to t...
