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Topic:Apoptosis
Apoptosis is a form of programmed cell death that is essential for maintaining cellular homeostasis and development in horses. This process involves a series of biochemical events leading to characteristic cell changes and death, which are crucial for removing damaged or unnecessary cells without eliciting an inflammatory response. In horses, apoptosis plays a role in various physiological and pathological conditions, including tissue remodeling, immune response regulation, and the progression of certain diseases. Studies on equine apoptosis explore the molecular mechanisms, regulatory pathways, and implications for health and disease management. This page compiles peer-reviewed research studies and scholarly articles that investigate the mechanisms, regulation, and significance of apoptosis in equine biology and medicine.
vCLAP, a caspase-recruitment domain-containing protein of equine Herpesvirus-2, persistently activates the Ikappa B kinases through oligomerization of IKKgamma. vCLAP, the E10 gene product of equine herpesvirus-2, is a caspase-recruitment domain (CARD)-containing protein that has been shown to induce both apoptosis and NF-kappaB activation in mammalian cells. vCLAP has a cellular counterpart, Bcl10/cCLAP, which is also an activator of apoptosis and NF-kappaB. Recent studies demonstrated that vCLAP activates NF-kappaB through an IkappaB kinase (IKK)-dependent pathway, but the underlying mechanism remains unknown. In this report, we demonstrate that vCLAP associates stably with the IKK complex through direct binding to the C-terminal region of IKKgamma....
Proliferation, DNA ploidy, p53 overexpression and nuclear DNA fragmentation in six equine melanocytic tumours. Melanocytic tumours are a well-known clinical and pathological entity in horses, but further phenotypic characterization of these tumours is lacking. Six melanocytic tumours from five horses (two metastatic and four benign) were examined by Ki67, PCNA and p53 immunostaining, DNA nick end labelling (Tunel) and Feulgen staining. The stainings were evaluated using quantitative image analysis. The resulting parameters of growth fraction (Ki67), S-phase index (PCNA), p53 index, apoptotic index, DNA index, nuclear diameter, ploidy balance, proliferation index (Feulgen) and hyperploidy were analysed....
Induction of apoptosis by equine arteritis virus infection. Equine arteritis virus (EAV) is the etiological agent of equine viral arteritis, a contagious viral disease of equids. EAV is the prototype virus of the arteriviruses, a group of small enveloped viruses with positive single-stranded RNA genomes. Because apoptosis or programmed cell death is believed to play an important role in the biogenesis of several cytopathogenic viruses, we examined whether EAV was able to induce cell apoptosis in vitro. To do this, Vero cells were infected with EAV at a multiplicity of infection of 0.1 tissue culture infectious dose (TCID50) per cell, and analyzed at va...
Effect of L-glutamine for freezing equine embryos: evaluation by DAPI staining and transfer of multiple embryos to recipient mares. Day 6.5 equine embryos (n=30) were frozen in a medium containing glycerol (2.5-10.0%) supplemented with 0, 20 or 100 mmol L-glutamine 1(-1). After thawing, the embryos were tested individually, using 4',6'-diamidino-2-phenylindole (DAPI) staining to evaluate cell death. Three embryos (one frozen at each L-glutamine concentration) were transferred together into individual recipient mares. Pregnancy diagnosis was performed at day 12 (age of embryo). Embryos were collected at day 14 (age of embryo) and were identified by PCR amplified microsatellite analysis. Nine of ten recipient mares that rece...
Apoptosis in equine granulosa cells and its relationship to cumulus expansion and oocyte chromatin configuration in ovarian follicles. During the oestrous cycle follicles grow and either ovulate or regress. Regressing follicles undergo atresia and in many species apoptosis has been identified as the underlying mechanism in this process. The aims of this study were to establish whether equine granulosa cells degenerate via an apoptotic mechanism and whether the presence of apoptotic cell death in granulosa cells is correlated with oocyte quality. Ovaries from mares at unknown stages of the oestrous cycle were obtained from an abattoir. In Expt 1, follicles (n=352) from 37 mares were processed. DNA was extracted from granulosa ...
Effects of Actinobacillus equuli culture supernatants on equine neutrophil functions and survival. After exposure of equine granulocytes from both foals and adult horses to culture supernatants from clinical isolates of Actinobacillus equuli, phagocytic capacity and respiratory burst was examined by flow-cytometry and a chemiluminescence assay, respectively. One haemolytic isolate of an equine Actinobacillus was also included in the study. An average decrease of 22% in total number of granulocytes, in the flow cytometric assay (P < 0.01), and an average decrease of 26% in light emission, in the chemiluminescence assay (P < 0.001), was seen after exposure to bacterial culture supernata...
Hepatocyte growth factor induces rat ovarian surface epithelial cell mitosis or apoptosis depending on the presence or absence of an extracellular matrix. The present studies showed that sequential treatment with equine CG (eCG) and hCG not only induced an increase in ovarian weight, but also caused an estimated 4.6-fold increase in the number of ovarian surface epithelial cells. In addition, eCG-hCG treatment increased ovarian hepatocyte growth factor (HGF) messenger RNA levels. These studies also demonstrated that rat primary ovarian surface epithelial cells as well as a cell line derived from rat ovarian surface epithelium (i.e. ROSE-179 cells) do not express the LH (hCG) receptor. Both of these cells express c-Met, the receptor for HGF. To a...
The neurology and enterology of equine grass sickness: a review of basic mechanisms. Autonomic dysfunction constitutes a prominent clinical feature of equine grass sickness (EGS). Significant injury to the nervous control of the alimentary system is life threatening, partly because of dysphagia but also because of the failure of the unique regulatory mechanisms in equine digestion involving water and electrolyte balance. The neuropathology also indicates the presence of a somatic polyneuropathy. The morphological features of EGS are similar to those of excitotoxic neuronal degeneration, which resembles neuronal apoptosis. It is difficult to ascertain from published accounts th...
Effects of insulin and insulin-like growth factors I and II on the growth of equine fetal and neonatal chondrocytes. The effects of insulin and insulin-like growth factors (IGFs) I and II on fetal and foal chondrocytes were investigated in vitro. Chondrocytes from the lateral trochlear ridge of the distal femur were obtained from 2 fetuses (280 and 320 days gestation) and one 4-day-old foal and cultured. Membrane proteins consistent with type 1 and type 2 IGF receptors were demonstrated by radioligand cross linking and equilibrium binding analysis. It was demonstrated that both IGF-I and IGF-II acted as mitogens for isolated equine chondrocytes when present as the sole mitogenic factor in monolayer culture. ...
Assessment of viability and mitochondrial function of equine spermatozoa using double staining and flow cytometry. An objective double-staining method was developed to evaluate viability and mitochondrial function of stallion spermatozoa using flow cytometry. Sperm viability was assessed by propidium iodide (PI) exclusion, and mitochondrial function was measured by the intensity of rhodamine 123 (R123) fluorescence. Flow cytometry estimates of sperm viability measured by PI were equivalent (P > 0.05) to estimates made using Hoechst 33258 stain and fluorescent microscopy (% dead: 25 +/- 2.4 vs 21.5 +/- 3.5). The use of both PI and R123 was validated by addition of various proportions of freeze-shocked (m...
The effect of exercise-induced localised hyperthermia on tendon cell survival. Tendons that store energy during locomotion, such as the equine superficial digital flexor tendon (SDFT) and human Achilles tendon, suffer a high incidence of central core degeneration which is thought to precede tendon rupture. Although energy storage contributes to the efficiency of locomotion, tendons are not perfectly elastic and some energy is lost in the form of heat. Recent studies have shown that the central core of equine SDFT reaches temperatures as high as 45 degrees C during high-speed locomotion. In this study, we test the hypothesis that hyperthermia causes tendon cell death and ...
Importance of sphingolipids and inhibitors of sphingolipid metabolism as components of animal diets. Sphingolipids are highly bioactive compounds that participate in the regulation of cell growth, differentiation, diverse cell functions, and apoptosis. They are present in both plant and animal foods in appreciable amounts, but little is known about their nutritional significance. Recent studies have shown that feeding sphingomyelin to female CF1 mice treated with a colon carcinogen (1,2-dimethylhydrazine) reduced the number of aberrant colonic crypt foci; longer-term feeding also affected the appearance of colonic adenocarcinomas. Therefore, dietary sphingolipids should be considered in studi...
A novel family of viral death effector domain-containing molecules that inhibit both CD-95- and tumor necrosis factor receptor-1-induced apoptosis. Molluscum contagiosum virus proteins MC159 and MC160 and the equine herpesvirus 2 protein E8 share substantial homology to the death effector domain present in the adaptor molecule Fas-associated death domain protein (FADD) and the initiating death protease FADD-like interleukin-1beta-converting enzyme (FLICE) (caspase-8). FADD and FLICE participate in generating the death signal from both tumor necrosis factor receptor-1 (TNFR-1) and the CD-95 receptor. The flow of death signals from TNFR-1 occurs through the adaptor molecule tumor necrosis factor receptor-associated death domain protein (TRA...
Dose-response of X-irradiated human and equine lymphocytes. We have investigated and compared DNA damage and cell killing induced in human and equine lymphocytes after in vitro X-irradiation. Our data show that the cytogenetic and the lethality effects are both greater in equine lymphocytes, but that the difference is wider for lethality. The ratios between doses inducing the same effect are 1.3, 1.7 and 9.4 for the number of binucleated cells with micronuclei, micronucleus frequency in binucleated cells and DNA synthesis inhibition, respectively. The very different radiosensitivity observed for the two mammalian species encourages us to use their lymp...
Leukoencephalomalacia and hemorrhage in the brain of rabbits gavaged with mycotoxin fumonisin B1. Two of five pregnant rabbits gavaged with purified fumonisin B1 at 1.75 mg/kg/day died, one after 9 and one after 13 doses. Microscopic examination revealed focal small hemorrhages in cerebral white matter in both animals, with malacia and hemorrhage also present in the hippocampus of one. The lesions were bilateral. Both animals also had marked degeneration of renal tubule epithelium and of hepatocytes. Apoptosis was the dominant degenerative change in kidney and liver. Fumonisin is known to cause leukoencephalomalacia and hemorrhage in equines, but CNS changes associated with exposure to fum...
The dose-related effects of phenylbutazone and a methylprednisolone acetate formulation (Depo-Medrol) on cultured explants of equine carpal articular cartilage. The dose-related effects of phenylbutazone and Depo-Medrol on chondrocyte viability and chondrocyte-mediated synthesis and depletion of proteoglycans were investigated using cultured explants of equine middle carpal joint articular cartilage. Explants from 12 horses (941 x 3 mm diameter) were cultured for a total of 5 days, which included 3 days' exposure to either phenylbutazone (0, 2, 20, 200 or 2000 micrograms/mL) or Depo-Medrol (0, 20, 200 or 2000 micrograms/mL). For each explant, amino sugar content was used as a measure of proteoglycan content, 35S incorporation as a measure of the rate ...
Effect of serum on intracellular calcium homeostasis and survival of primary cortical and hippocampal CA1 neurons following brief glutamate treatment. Glutamate neurotoxicity was studied in primary neuronal cultures prepared from rat cerebral cortex and hippocampal CA1 sector. Neurons were cultivated with 5% native horse serum and then exposed to 0.1 or 1.0 mM glutamate for 5 min. Subsequently, neurons were allowed to recover for 24 hours either in the presence or in the absence of 5% native horse serum. In the absence of serum, neurons showed morphological signs of degeneration and exhibited marked loss of vitality as tested by vital staining and release of lactate dehydrogenase (LDH). In contrast, when neurons were cultivated in the presen...
Quantitative analysis of morphological modifications of day 6.5 horse embryos after cryopreservation: differential effects on inner cell mass and trophoblast cells. Sixteen embryos were recovered nonsurgically at day 6.5 after induced ovulation from Welsh pony mares and were evaluated for cellular changes that occur because of exposure to the cryoprotectant with or without the freeze and thaw process. Day 6.5 horse embryos were either (i) frozen and thawed using glycerol as cryoprotectant (n = 6), (ii) given only the glycerol treatment (n = 5), or (iii) washed in phosphate-buffered saline (PBS) the same number of times as in the glycerol treatment (n = 5). After treatments, embryos were incubated in Minimum Essential Medium (MEM), supplemented with BSA, g...
Ultrastructure of cryopreserved horse embryos. Embryos were recovered non-surgically at about Day 6 after ovulation from 15 Quarter horse-type mares and were evaluated for morphological changes which may occur because of exposure to the cryoprotectant and/or cryopreservation. Electron microscopy was used to elucidate the fine structure of intracellular organelles which, if damaged, could cause cellular death. The horse embryo does not totally re-expand in the 10% glycerol freezing medium, nor will it completely re-expand in the isotonic holding medium following glycerol removal whether or not the embryo has been frozen. Embryos in this stu...
Comparison of the lipoprotein profiles obtained from rat, bovine, horse, dog, rabbit and pig serum by a new two-step ultracentrifugal gradient procedure. A new two-step gradient technique has been used in the separation of the different classes of lipoproteins from the serum of cows, horses, dogs, pigs, rabbits and rats. Total lipoproteins were first isolated at d 1.21 then floated through a d 1.006 to d 1.21 gradient. Collection by mean of a gradient fractionator provided directly comparable lipoprotein profiles, allowed the determination of the exact density range of each lipoprotein class and the fraction by fraction analysis of composition. Cholesterol and apo AI recoveries were high. Horse, dog, rabbit and pig exhibited three distinct lipo...
Spermidine cytotoxicity in vitro: effect of serum and oxygen tension. Plasma amine oxidase activities (benzylamine oxidase and spermine oxidase) were determined in the sera of a number of species of various ages. Benzylamine oxidase (BZO) activity, measured spectrophotometrically, was present in bovine, equine, and ovine species examined. Generally its activity in serum increased with the age of the animal. Spermine oxidase activity (SPO) was estimated by a bioassay of in vitro toxicity and did not necessarily correlate with BZO. Cytotoxicity in the presence of spermidine was found only in the sera of the ruminant species examined. Serum activity tended to rise ...
Comparative studies of the effect of thermal stimulation on the permeability of the luminal cell junctions of the sweat gland to lanthanum. Lanthanum injected intradermally in vivo into the skin of cattle, sheep, goats and ponies penetrated the intercellular spaces of the sweat glands. It was not, however, detected in the glandular lumen either visually or by electron probe microanalysis even at elevated ambient temperatures when the animals were sweating. It is concluded that the luminal intercellular connections between epithelial cells in these glands are tight junctions, which remain so during sweating despite the occurrence of cell death and extrusion into the lumen.
