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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.
Clinical utility of serum biochemical variables for predicting acid-base balance in critically ill horses. Profiles from serum biochemical analyzers include the concentration of strong electrolytes (including l-lactate), total carbon dioxide (tCO2 ), and total protein. These variables are associated with changes in acid-base balance. Application of physicochemical principles may allow predicting acid-base balance from serum biochemistry without measuring whole blood pH and pCO2 . Objective: The purpose of the study was to determine if the acid-base status of critically ill horses could be accurately predicted using variables included in standard serum biochemical profiles. Methods: Two jugular veno...
Effects of milk proteins on sperm binding to the zona pellucida and intracellular Ca(2+) concentration in stallion sperm. Objectives were to determine the effects of extracellular Ca(2+) and milk proteins on intracellular Ca(2+) concentrations in stallion sperm; and to determine the effects of single caseins on sperm binding to the zona pellucida (ZP). In Experiment I, sperm were incubated in media containing 2 or 4mM Ca(2+) and intracellular Ca(2+) concentration was determined after ionomycin treatment and long-term incubation (3h). Extracellular Ca(2+) concentrations (2 compared with 4mM) did not affect baseline intracellular Ca(2+) concentration of sperm. However, incubating sperm in a medium containing 4 comp...
Determining ACTB, ATP5B and RPL32 as optimal reference genes for quantitative RT-PCR studies of cryopreserved stallion semen. Equine germplasm bank management involves not only the conservation and use of semen doses, in addition it can also be a resource to study stallion semen quality and after thawing semen properties for reproductive purposes. A possible criterion to measure quality may be based on differential gene expression of loci involved during spermatogenesis and sperm quality maturation. The rapid degradation of sperm after thawing affects the integrity and availability of RNA. In this study we have analyzed genes expressed in equine cryopreserved sperm, which provided an adequate amplification, specifici...
Characterization of butyrate transport across the luminal membranes of equine large intestine. The diet of the horse, pasture forage (grass), is fermented by the equine colonic microbiota to short-chain fatty acids, notably acetate, propionate and butyrate. Short-chain fatty acids provide a major source of energy for the horse and contribute to many vital physiological processes. We aimed to determine both the mechanism of butyrate uptake across the luminal membrane of equine colon and the nature of the protein involved. To this end, we isolated equine colonic luminal membrane vesicles. The abundance and activity of cysteine-sensitive alkaline phosphatase and villin, intestinal luminal ...
Suberoylanilide hydroxamic acid (vorinostat): its role on equine corneal fibrosis and matrix metalloproteinase activity. To explore the effect of suberoylanilide hydroxamic acid (SAHA) (i) on corneal fibroblast differentiation, morphology, and viability; and (ii) on the expression levels of matrix metalloproteinases (MMPs) 2 and 9 using an in vitro model of equine corneal fibrosis. Methods: Healthy donor corneas were used to generate primary cultures of equine corneal fibroblasts. The fibroblasts were exposed to 5 ng/mL TGFβ1 to induce myofibroblast formation. The cultures were treated with either 5 μm or 10 μm SAHA for 72 h in the presence of TGFβ1. Real-time PCR and immunocytochemistry were used to determi...
Ultrashort cationic naphthalene-derived self-assembled peptides as antimicrobial nanomaterials. Self-assembling dipeptides conjugated to naphthalene show considerable promise as nanomaterial structures, biomaterials, and drug delivery devices. Biomaterial infections are responsible for high rates of patient mortality and morbidity. The presence of biofilm bacteria, which thrive on implant surfaces, are a huge burden on healthcare budgets, as they are highly resistant to current therapeutic strategies. Ultrashort cationic self-assembled peptides represent a highly innovative and cost-effective strategy to form antibacterial nanomaterials. Lysine conjugated variants display the greatest po...
Nestin expression in mesenchymal stromal cells: regulation by hypoxia and osteogenesis. The intermediate filament protein nestin is used as a marker for neural stem cells, and its expression is inversely correlated with cellular differentiation. More recently, nestin expression has also been described in other cell types including multipotential mesenchymal stromal cells (MSCs). In this study, we examined the expression of nestin in equine, canine and human bone marrow-derived MSCs undergoing osteogenic differentiation, to determine whether nestin levels were attenuated as the cells acquired a more mature phenotype. In addition, the expression of nestin may be under the influence...
Pituitary pars intermedia dysfunction does not necessarily impair insulin sensitivity in old horses. Equine pituitary pars intermedia dysfunction (PPID) has been associated with reduced insulin sensitivity in comparison with younger adult horses; however, the difference in insulin sensitivity between horses with PPID and aged-matched controls has not been well characterized. The objective of the study was to determine if aged horses with PPID had reduced insulin sensitivity and alterations in the insulin-mediated signaling pathways in the skeletal muscle when compared with healthy aged horses. Isoglycemic hyperinsulinemic clamp procedures were conducted in 12 horses that were classified as ei...
Gene expression of matrix metalloproteinases and LH receptors in mare follicular development. The period from the emergence of a dominant follicle until its formation requires tissue remodeling. Enzymes promoting collagen lysis, such as matrix metalloproteinases (MMPs), are fundamental for the process of extracellular matrix remodeling, which allows changes in ovarian tissue architecture during follicular growth. It has been suggested that the production of these enzymes may be affected by the rise in circulating concentrations of LH, which acts on the ovarian surface epithelium (OSE). The aim of this study was to determine the expression of MMP-1, MMP-2, and LH receptor (LHR) in the o...
Comparison of healing in forelimb and hindlimb surgically induced core lesions of the equine superficial digital flexor tendon. Even though equine multi-limb tendinopathy models have been reported, it is unknown if fore- and hindlimb tendon healing behave similarly. The aim of this study was to compare the healing process of surgically induced superficial digital flexor tendon (SDFT) core lesions of fore- and hindlimbs in horses. Methods: Tendon core lesions were surgically induced in the SDFT of both fore- and hindlimbs in eight horses. One randomly assigned forelimb and one randomly assigned hindlimb were injected with saline one and two weeks post-surgery. The healing process was monitored clinically and ultrasonogr...
Proteomic analysis reveals age-related changes in tendon matrix composition, with age- and injury-specific matrix fragmentation. Energy storing tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), are highly prone to injury, the incidence of which increases with aging. The cellular and molecular mechanisms that result in increased injury in aged tendons are not well established but are thought to result in altered matrix turnover. However, little attempt has been made to fully characterize the tendon proteome nor determine how the abundance of specific tendon proteins changes with aging and/or injury. The aim of this study was, therefore, to assess the protein profile of normal SDFTs ...
Identification of interspecific differences in phase II reactions: determination of metabolites in the urine of 16 mammalian species exposed to environmental pyrene. Interspecific differences in xenobiotic metabolism are a key to determining relative sensitivities of animals to xenobiotics. However, information on domesticated livestock, companion animals, and captive and free-ranging wildlife is incomplete. The present study evaluated interspecific differences in phase II conjugation using pyrene as a nondestructive biomarker of polycyclic aromatic hydrocarbon (PAH) exposure. Polycyclic aromatic hydrocarbons and their metabolites have carcinogenic and endocrine-disrupting effects in humans and wildlife and can have serious consequences. The authors collec...
Adeno-associated viral vectors show serotype specific transduction of equine joint tissue explants and cultured monolayers. Adeno-associated virus (AAV) receptors range from heparan sulfate proteoglycan to sialic acid moieties present on cell surfaces. Abundance of the glycan profiles is greatly influenced by animal species, cell type, and culture conditions. The objective of this study was to determine whether AAV serotypes' transduction efficiencies specifically in the equine monolayer culture model are an accurate representation of transduction efficiencies in tissue explants, a model more closely related to in vivo transduction. It was found that AAV 2 and 2.5 transduced cells more efficiently in explants than ...
Antioxidant activity of hyaluronic acid investigated by means of chemiluminescence of equine neutrophil bursts and electron paramagnetic resonance spectroscopy. Activated neutrophils (PMNs), the ROS/RNS released by PMNs and the derived inflammatory processes are involved in the pathogenesis and progression of human inflammatory airway diseases. Similar diseases are also present in horses which suffer from recurrent airway obstruction (RAO), exercise-induced pulmonary haemorrhage (EIPH) and inflammatory airway diseases (IAD). Hyaluronic acid (HA) plays numerous roles in modulating inflammatory processes. The aim of this study was to examine whether a preparation of HA (MW 900 000 Da) interferes with ROS/RNS during the course of equine PMN respiratory b...
Opposing roles of leptin and ghrelin in the equine corpus luteum regulation: an in vitro study. Metabolic hormones have been associated with reproductive function modulation. Thus, the aim of this study was: (i) to characterize the immunolocalization, mRNA and protein levels of leptin (LEP), Ghrelin (GHR) and respective receptors LEPR and Ghr-R1A, throughout luteal phase; and (ii) to evaluate the role of LEP and GHR on progesterone (P4), prostaglandin (PG) E2 and PGF2α , nitric oxide (nitrite), tumor necrosis factor-α (TNF); macrophage migration inhibitory factor (MIF) secretion, and on angiogenic activity (BAEC proliferation), in equine corpus luteum (CL) from early and mid-luteal sta...
A fast method for the determination of the PC/LPC ratio in intact serum by MALDI-TOF MS: an easy-to-follow lipid biomarker of inflammation. The PC/LPC ratio of blood serum is increasingly considered to represent an important clinical parameter that reflects various kinds of diseases. Here, a simple and fast method of lipid analyses of "intact" blood serum (i.e. without extraction) by MALDI-TOF mass spectrometry is described. The novel procedure allows the accurate determination of the PC/LPC ratio, utilizing only a tiny amount of blood. The serum is diluted with distilled water and directly applied onto the MALDI target and, after drying, covered by a thin layer of the matrix solution (either 9-aminoacridine or 2,5-dihydroxybenzoi...
Equine digital veins are more sensitive to superoxide anions than digital arteries. This work was designed to investigate (i) the effect of superoxide dismutase (SOD) inhibition on endothelial function and (ii) the free radical-induced endothelial dysfunction in equine digital veins (EDVs) and equine digital arteries (EDAs) isolated from healthy horses. EDV and EDA rings were suspended in a 5 ml organ bath containing Krebs solution. After a 60 min equilibration period, EDV and EDA rings were contracted with phenylephrine. Then, cumulative concentration-response curves (CCRCs) to acetylcholine were performed. In both EDVs and EDAs, acetylcholine (1 nM to 10 µM) produced conce...
Proteomic analysis of equine amniotic membrane: characterization of proteins. Human amniotic membrane (AM) has been used as a biomaterial for surgical wound skin and ocular surface reconstruction for several years. Currently, equine AM has been used for corneal reconstruction in several animal species, and appears to have the same properties as human AM. Despite the observed positive healing abilities of this tissue in horses with ulcerative keratitis the proteins of equine AM have not been described. Objective: To identify proteins known to be associated with corneal healing from frozen equine AM. Methods: Placentas were acquired from healthy live foal births from a lo...
Whole-body phenylalanine kinetics and skeletal muscle protein signaling in horses with pituitary pars intermedia dysfunction. To compare whole-body phenylalanine kinetics and the abundance of factors in signaling pathways associated with skeletal muscle protein synthesis and protein breakdown between horses with pituitary pars intermedia dysfunction (PPID) and age-matched control horses without PPID. Methods: 12 aged horses (6 horses with PPID and 6 control horses; mean age, 25.0 and 25.7 years, respectively). Methods: Plasma glucose, insulin, and amino acids concentrations were determined before and 90 minutes after feeding. Gluteal muscle biopsy samples were obtained from horses 90 minutes after feeding, and the ab...
Transcriptional expression changes of glucose metabolism genes after exercise in thoroughbred horses. Physical exercise induces gene expression changes that trigger glucose metabolism pathways in organisms. In the present study, we monitored the expression levels of LDHA (lactate dehydrogenase) and GYS1 (glycogen synthase 1) in the blood, to confirm the roles of these genes in exercise physiology. LDHA and GYS1 are related to glucose metabolism and fatigue recovery, and these processes could elicit economically important traits in racehorses. We collected blood samples from three retired thoroughbred racehorses, pre-exercise and immediately after 30 min of exercise. We extracted total RNA and ...
Glutamate and lipid metabolic perturbation in the hippocampi of asymptomatic borna disease virus-infected horses. Borna disease virus (BDV) is a neurotropic, enveloped, non-segmented, negative-stranded RNA virus that infects a wide variety of vertebrate species from birds to humans across a broad global geographic distribution. Animal symptomatology range from asymptomatic infection to behavioral abnormalities to acute meningoencephalitis. Asymptomatic BDV infection has been shown to be more frequent than conventionally estimated. However, the molecular mechanism(s) underyling asymptomatic BDV infection remain largely unknown. Here, based on real-time quantitative PCR and Western blotting, a total of 18 h...
Post-mortem stability of RNA in skeletal muscle and adipose tissue and the tissue-specific expression of myostatin, perilipin and associated factors in the horse. Obesity, a major concern for equine welfare, is highly prevalent in the leisure horse population. Skeletal-muscle and adipose tissues are important determinants of maintenance energy requirements. The myostatin and perilipin pathways play key roles in the regulation of muscle mass and lipolysis respectively and have both been associated with obesity predisposition in other mammalian species. High quality samples, suitable for molecular biology, are an essential prerequisite for detailed investigations of gene and protein expression. Hence, this study has evaluated a) the post-mortem stability ...
The effects of chemical and physical penetration enhancers on the percutaneous permeation of lidocaine through equine skin. The effect of physical and chemical permeation enhancers on in vitro transdermal permeation of lidocaine was investigated in the horse.Therefore, the effect of six vehicles (phosphate-buffered saline (PBS), 50% ethanol, 50% propylene glycol, 50% isopropylalcohol, 50% isopropylalcohol/isopropylmyristate and 50% dimethylsulfoxide) was examined as well as the effect of microneedle pretreatment with different needle lengths on transdermal drug delivery of lidocaine.The skin was obtained from the thorax of six Warmblood horses and was stored up to two weeks at - 20°C. Franz-type diffusion cells we...
Effect of non-native helix destabilization on the folding of equine β-lactoglobulin. β-lactoglobulin forms a non-native α-helix during an early stage of folding. To address the role of the non-native structure in the folding process, we designed several mutants of equine β-lactoglobulin with reduced helical propensity in the non-native helix region. One of them, A123T, showed a similar structure to that of the wild-type protein; its folding kinetics was investigated by stopped-flow circular dichroism (CD) and fluorescence. Although A123T showed a reduced burst-phase CD intensity, its folding rate was similar to that of the wild-type protein, which indicated that the formati...
Comparison of two methods for measurement of equine insulin. Diagnosis of equine hyperinsulinemia requires an accurate method for quantification of equine insulin concentrations. The objectives of the current study were to compare 2 commercially available techniques for measurement of equine insulin, the radioimmunoassay (RIA) and chemiluminescent immunoassay (CIA). Recovery was poor for both assays, but worse for the CIA. Serial dilution of a high endogenous insulin sample yielded better linearity for the RIA ( r = 0.99, P < 0.001) than the CIA ( r = 0.92, P = 0.009). Bland-Altman analysis indicated that the CIA was, on average, 91 pmol/l higher tha...
Caspase activation, hydrogen peroxide production and Akt dephosphorylation occur during stallion sperm senescence. To investigate the mechanisms inducing sperm death after ejaculation, stallion ejaculates were incubated in BWW media during 6 h at 37°C. At the beginning of the incubation period and after 1, 2, 4 and 6 h sperm motility and kinematics (CASA), mitochondrial membrane potential and membrane permeability and integrity were evaluated (flow cytometry). Also, at the same time intervals, active caspase 3, hydrogen peroxide, superoxide anion (flow cytometry) and Akt phosphorylation (flow cytometry) were evaluated. Major decreases in sperm function occurred after 6 h of incubation, although after 1 h ...
Equine trypanosomosis in central and western Punjab: prevalence, haemato-biochemical response and associated risk factors. The detection of Trypanosoma evansi in blood is intricate, primarily in chronic stage of infection, as the parasitaemia is often low and fluctuating. The climatic conditions of the target area of Punjab (a province of India with a total of 34,000 horses and ponies used for sports and transport) are conducive for the parasite propagation. The objective of present investigation was to assess the prevalence of T. evansi in central and western Punjab by PCR and card agglutination test (CATT/T. evansi) in relation to clinico-haematobiochemical alterations and risk factors associated with latent try...
Equine autologous platelet concentrates: A comparative study between different available systems. Autologous platelet concentrates (APCs) are being used increasingly in horses to enhance regeneration in tissues that have poor natural healing capabilities. Numerous APC systems, which are based on different preparation techniques and were originally developed for human patients, are now routinely used in equine cases. However, preliminary process validation and adequate in vitro biochemical characterisation of most of these systems do not exist for horses. Objective: To compare haematological findings and growth factor concentrations of equine APCs obtained with 4 commercially available syst...
Naturally and stimulated levels of reactive oxygen species in cooled stallion semen destined for artificial insemination. The decrease in foaling rates after artificial insemination with cooled semen warrants the search for new predictors of fertility. The objectives were to investigate levels of naturally occurring reactive oxygen species (ROS) in cooled, stored stallion semen doses for artificial insemination (AI), and their relationship with parameters of semen quality and with pregnancy rate. Semen was collected from warmblood stallions (n=15) and used to prepare commercial semen doses for AI. Sperm quality was evaluated after cooled transport to the laboratory overnight. The results were correlated with obse...
Dietary crude protein intake influences rates of whole-body protein synthesis in weanling horses. The objective of this study was to measure whole-body protein kinetics in weanling horses receiving forage and one of two different concentrates: (1) commercial crude protein (CCP) concentrate, which with the forage provided 4.1 g CP/kg bodyweight (BW)/day (189 mg lysine (Lys)/kg BW/day), and (2) recommended crude protein (RCP) concentrate which, with the same forage, provided 3.1 g CP/kg BW/day (194 mg Lys/kg BW/day). Blood samples were taken to determine the response of plasma amino acid concentrations to half the daily concentrate allocation. The next day, a 2 h-primed, constant inf...
