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Topic:Inflammatory Response
The inflammatory response in horses is a complex physiological process that occurs when the immune system reacts to harmful stimuli such as pathogens, damaged cells, or irritants. This response is characterized by the activation of various immune cells, the release of signaling molecules, and the production of inflammatory mediators. In horses, the inflammatory response involves both innate and adaptive immune mechanisms, which work together to eliminate the source of harm and initiate tissue repair. Key components of the equine inflammatory response include cytokines, chemokines, and leukocytes, which coordinate the body's defense and healing processes. This page gathers peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of the inflammatory response in equine health and disease.
Plasma and synovial fluid kinetics, disposition, and urinary excretion of naproxen in horses. Naproxen (+6-methoxy-[alpha-methyl]-2-naphthalene acetic acid) is a nonsteroidal anti-inflammatory drug that is used for the treatment of inflammatory conditions in horses. We developed a model that describes the drug's disposition and renal excretion, including synovial fluid disposition and elimination after IV administration in horses. The plasma disposition, after IV administration of 5 mg/kg of body weight, was described by a two-compartment model; mean +/- SD distribution and elimination half-lives were 1.42 +/- 0.42 and 8.26 +/- 2.56 hours, respectively. Plasma concentration of naproxen...
Comparison of the anti-inflammatory actions of flunixin and ketoprofen in horses applying PK/PD modelling. A comparative study in horses of the pharmacokinetics (PK) and pharmacodynamics (PD) of 2 extensively used nonsteroidal anti-inflammatory drugs (NSAIDs), flunixin (FXN) and ketoprofen (KTP), was carried out applying PK/PD modelling. To evaluate the anti-inflammatory properties of these drugs a model of acute inflammation, comprising surgically implanted subcutaneous tissue cages stimulated by intracaveal injection of carrageenan, was used. FXN elimination half-life (T1/2 beta) in plasma was 3.37 +/- 1.09 h. However, in exudate a much longer T1/2 beta was obtained (15.99 +/- 3.80 h). Apparent v...
Bronchoalveolar lavage in horses: effect of exercise and repeated sampling on cytology. Bronchoalveolar lavage (BAL) was performed at weekly intervals in 10 Thoroughbred horses in race training (group 1) and in 4 rested horses (group 2) for 10 weeks. Lavages were continued on a weekly basis in 4 group 1 horses for an additional 9 weeks (group 3). Cytological analysis of samples included leukocyte counts, erythrocyte counts, differential leukocyte counts, and haemosiderophage score. The mean leukocyte concentration was significantly lower in group 1 (92.1 +/- 4.6 cells/microL) when compared with group 2 (133.5 +/- 8.2 cells/microL), P = 0.037. The differential leukocyte data were ...
Induction of intra-articular tumour necrosis factor during acute inflammatory responses in equine arthritis. Synovial fluid (SF) was collected at 2, 12 and 26 h post racing from 5 Thoroughbred horses (6 joints) with degenerative joint disease. The effects of serial arthrocentesis on SF TNF alpha levels were controlled for by testing, in parallel, site- and time-matched samples from clinically normal horses (i.e. without arthritis). A significant induction in TNF alpha bioactivity was detected in SF from arthritic joints (compared to the control joints) over the 26 h following racing. After subtraction of values for the arthrocentesis control SF, TNF alpha and protein levels and WBC and mononuclear ce...
The pathogenesis of chronic obstructive pulmonary disease of horses. Present evidence suggests that chronic obstructive pulmonary disease (COPD) of horses is a delayed hypersensitivity response to inhaled antigens, particularly the thermophilic moulds and actinomycetes that grow in damp hay. Within several hours of exposing COPD-susceptible horses to such hay, neutrophils invade the lung and accumulate in the lumens of airways, particularly bronchioles. The inflammatory response is accompanied by increased levels of histamine in bronchoalveolar lavage fluid, increased plasma levels of the inflammatory mediators thromboxane and 15-hydroxyeicosatetraenoic acid (1...
Cytologic evaluation of bronchoalveolar lavage fluid obtained from standardbred racehorses with inflammatory airway disease. Cytologic examination of bronchoalveolar lavage fluid (BALF), including phenotypic analysis of lymphocytes, was performed on 32 Standardbreds with poor race performance and endoscopic examination findings characteristic of inflammatory airway disease (IAD). Nucleated cell counts in BALF from IAD-affected horses were higher than those in control horses; the cytologic profile of BALF in affected horses included mixed inflammation, characterized by mild neutrophilia, lymphocytosis, and monocytosis. Eosinophil and mast cell counts were not higher in the IAD-affected group, compared with those in t...
Overview of equine papular and nodular dermatoses. Papules and nodules are common lesions on horses and have a variety of underlying causes. This article addresses inflammatory and congenital nodules primarily, including urticaria, erythema multiforme, those nodules caused by infectious agents, epidermoid and dermoid cysts, and the uniquely equine skin tumor, the sarcoid. The eosinophilic nodules and other tumors are covered elsewhere in this issue. Diagnostic and therapeutic approaches to each of the diseases are emphasized.
Horse trophoblasts produce tumor necrosis factor alpha but not interleukin 2, interleukin 4, or interferon gamma. The distribution of four cytokines was analyzed in the endometrium and trophoblast of the horse between Days 30 and 55 of gestation. Endometrial tissues, invasive trophoblast (chorionic girdle), and noninvasive trophoblast (chorion and allantochorion) were examined separately. Cytokine expression was determined by amplification of specific mRNA via the reverse transcriptase polymerase chain reaction (RT-PCR). Messenger RNA for interleukin 2 (IL-2), interleukin 4 (IL-4), and interferon gamma (IFN gamma) was detected in endometrial tissues, unstimulated peripheral blood lymphocytes, and control ...
Prostaglandin F2 alpha metabolite levels following an embryo transfer procedure in the mare. Hormonal, chemical, and mechanical stimuli can activate the arachidonic acid cascade and result in formation of prostaglandins and related substances. These compounds can have a profound role in the initiation of the inflammatory process (Higgins & Lees 1984). Prostaglandin (PG) F2α is the key hormone in reproductive physiology with well-known effects on reproductive performance e.g. luteolysis and abortion. An activation of the arachidonic acid cascade, caused by mechanical manipulation during an embryo transfer procedure, might be one explanation for early embryonic loss.
Platelet activating factor mimics antigen-induced cutaneous inflammatory responses in sweet itch horses. Hypersensitivity responses to biting flies such as Culicoides are believed to be the cause of sweet itch, a seasonal intensely pruritic skin condition of horses. Little is known about the mediators released by antigen in the skin of affected horses. In the present study the cutaneous vascular and cellular responses to intradermally injected platelet activating factor (PAF) have been characterised in sweet itch cases during the active phase of the disease and compared with those of Culicoides antigen extract. Histamine was used as a positive control in vascular permeability studies. Responses w...
Fibrinolytic activity in plasma from horses with gastrointestinal diseases: changes associated with diagnosis, surgery, and outcome. Plasma fibrinolytic activity was evaluated over 5 consecutive days in 59 horses admitted to the Large Animal Teaching Hospital with acute gastrointestinal diseases. Only horses hospitalized for at least 5 days were included in the study. Tissue plasminogen activator (tPA) and plasminogen activator inhibitor type-1 (PAI-1) were quantitated using standard chromogenic activity assays. Statistical analyses were performed using analysis of variance; differences were considered significant when P < or = .05. Activity of PAI-1, the primary endogenous inhibitor of fibrinolysis, was significantly in...
Anti-inflammatory and immune support in endotoxemia and septicemia. Endotoxemia and septicemia are encountered frequently in equine veterinary practice. The deleterious effects of endotoxin are related to the severity of the response of the host's inflammatory system. Consequently, it is imperative that appropriate steps be taken to identify animals at risk of developing endotoxemia or septicemia, and to initiate treatments that will reduce the inflammatory response. This article discusses the anti-inflammatory and immune support of horses and foals with endotoxemia and septicemia.
Synovial fluid parameters in normal and osteochondritic hocks of horses with open physis. An investigation was carried out on most common synovial fluid parameters of normal and osteochondritic hocks of horses less than 12 months old in order to confirm the presence of an inflammatory process. Furthermore, a spectroscopic study was performed on synovial fluid from both normal and diseased hocks. A depolymerization of hyaluronic acid was demonstrated in synovial fluid from diseases joints, similar to that reported in human rheumatoid arthritis. A one month rest seem to normalize all parameters considered and in one joint, a return to normal infrared spectrum was demonstrated.
Histological findings in corneal stromal abscesses of 11 horses: correlation with cultures and cytology. Histopathology was compared to culture results and cytology from horses with corneal stromal abscess at the Auburn University and the Ohio State University Veterinary Teaching Hospitals. Significant bacteria were not isolated in culture or seen on histopathology in any of the horses. Although most bacteria infecting equine corneas can be isolated with blood and MacConkey's agars, failure to detect bacterial growth may not rule out infection because anaerobic or intracellular bacteria would not be isolated. The inability to visualise bacterial organisms on histological sections did not rule out...
The potential for dietary polyunsaturated fatty acids in domestic animals. The metabolism and clinical potential for dietary polyunsaturated fatty acids (PUFAs) modifications using oil supplements containing n-3 and n-6 fatty acids are reviewed. Their use in such disorders as renal disease, inflammatory and immune-related disorders, and dermatological conditions in dogs and cats is discussed. The influence of n-3 fatty acid-rich rations on the endotoxin response in horses is described. Progress has been made toward understanding the clinical potential for PUFAs in these species. However, they have not yet been shown to be efficacious in any of the conditions investig...
Effect of bacterial lipopolysaccharides on sulfated glycosaminoglycan metabolism and prostaglandin E2 synthesis in equine cartilage explant cultures. The metabolic responses of equine articular cartilage to incubation with bacterial lipopolysaccharide (LPS) were studied, using explant cultures of articular cartilage obtained from the metatarsophalangeal joints of 15 horses, age of which ranged from 3 months to 20 years. For comparison, explants were also established from the metatarsophalangeal joints of 3 calves. Explants were cultured for 3 days in medium containing various concentrations of LPS from 0 (control) to 100 micrograms/ml. Glycosaminoglycan (GAG) released during the 3-day incubation was determined by a spectrophotometric assay,...
An investigation of the proteoglycan metabolism of mature equine articular cartilage and its regulation by interleukin-1. The effect of human recombinant interleukin-1 beta (rhIL-1 beta) on proteoglycan metabolism was investigated in cultures of full thickness explants of articular cartilage from horses 3-21 years of age. Proteoglycan synthesis was inhibited at all ages but no alteration in the hydrodynamic size or electrophoretic heterogeneity was observed in proteoglycan isolated from rhIL-1 beta stimulated cartilage. The sulphation pattern of the newly synthesised proteoglycan molecules was, however, significantly affected by the presence of the peptide regulatory factor. Interleukin-1 had no effect on the rat...
Sperm-induced leukocytosis in the equine uterus. The objective of this study was to investigate the inflammatory reaction induced in the equine uterus by insemination with fresh and frozen semen. Eleven groups (6 to 8 mares per group) were studied during 2 breeding seasons. The mares were inseminated using raw semen, frozen semen, extended fresh and frozen semen, concentrated fresh semen, seminal plasma and seminal extenders only. One group was bred naturally. Six hours after insemination, the uteri were flushed with 50 ml of phosphate-buffered saline (PBS). Seventeen out of 104 samples (16%) exhibited slight bacterial growth. Neutrophil con...
Effect of interleukin 1 on articular cartilage from young and aged horses and comparison with metabolism of osteoarthritic cartilage. The effect of interleukin 1 (IL-1) on equine articular cartilage was investigated, using a cartilage explant culture system. Measurement of [35S]O4 incorporation revealed synthesis of matrix proteoglycan by cartilage to be decreased 45, 59.7, and 37.5% after 1, 3, and 5 days, respectively, in culture in the presence of 5 U of IL-1/ml. There was no change in proteoglycan degradation as determined by measurement of [35S]O4 release into the culture medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cartilage-conditioned medium indicated that exposure of cartilage to IL-1 caused ...
Substance P innervation of equine synovial membranes: joint differences and neural and nonneural receptor localizations. Substance P (SP) immunocytochemistry and receptor autoradiography were used to define the innervation of the equine synovial membrane of joints equivalent to the wrist and knuckle of man. SP-immunoreactive fibers were mainly concentrated around blood vessels in the subsynovial layer, although not exclusively, while in the more distal joint, SP fibers were more frequently seen in the synovial surface layer. Iodinated SP receptor autoradiography studies revealed silver grain concentrations in the advential layer of blood vessels associated with the vasa vasorum, on the vascular endothelium and i...
Generation and partial characterization of an eosinophil chemotactic cytokine produced by sensitized equine mononuclear cells stimulated with Strongylus vulgaris antigen. Supernatants generated by stimulation of peripheral blood mononuclear cells (PBMC) from Strongylus vulgaris sensitized or immunized ponies were assayed in vitro for eosinophil chemotactic activity (ECA) using the filter system in blind well chambers. The supernatants from these cultures were chemotactic for eosinophils, but not for neutrophils. Supernates from cultures of unsensitized PBMC stimulated with S. vulgaris antigen were not chemotactic for eosinophils. ECA was first detected in culture supernatants after 1.5 h of incubation and was dependent on both antigen and PBMC concentrations, b...
Evaluation of local endobronchial antigen challenges in the investigation of equine chronic obstructive pulmonary disease. Local transendoscopic endobronchial antigen challenge, which has proved to be a valuable clinical and research technique in the study of human pulmonary hypersensitivity, was evaluated in control and asymptomatic COPD--affected horses. Transendoscopic endobronchial challenges with phosphate-buffered saline (PBS), Micropolyspora faeni extract at 60 and 600 micrograms/ml and mouldy hay extract elicited neutrophilic airway inflammatory responses in control (N = 5-7) and asymptomatic COPD-affected (N = 5-7) horses, as determined by cytological examinations of bronchoalveolar lavage fluid (BALF) ha...
Correlations between histologic endometrial lesions in mares and clinical response to intrauterine exposure with Streptococcus zooepidemicus. The relationship between histologic lesions in endometrial biopsy specimens and susceptibility to chronic uterine infection (CUI) in mares was investigated. Mares were allotted to 4 groups on the basis of degree of endometrial lesions. Mares in group 1 (n = 6) had no pathologic changes, mares in group 2 (n = 5) had only mild pathologic changes, group-3 mares (n = 7) had moderate changes, and group-4 mares (n = 7) had severe inflammatory and fibrotic endometrial changes. Susceptibility to CUI was determined by the inflammatory response to intrauterine inoculation of 5 x 10(6) Streptococcus zooe...
The contribution of complement to opsonic activity in the uterine secretions of mares free of endometritis. The aim of the present study was to investigate if complement contributes to opsonic activity in the uterine secretions of mares with normal reproductive functions. Five mares with a mean age of 9 years were used in the study. The mares were considered to be free of endometritis based upon clinical history, palpation per rectum and ultrasonogaraphy of the genital tract, videoendoscopic inspection of the uterus, electronmicroscopy of endometrial biopsies, and bacteriological and cytological examination of swabs from the endometrium. The hormonal status of the mares was also determined. Uterine ...
Free radical oxidation products in plasma and synovial fluid of horses with synovial inflammation. Free radical oxidation products, namely conjugated dienes, ultraviolet fluorescence (excitation 325 nm, emission 395 nm) and visible fluorescence (excitation 360 nm, emission 460 nm) were measured in equine synovial fluid exposed to free radicals in vitro and in the plasma and synovial fluids of horses with synovial effusions. The synovial effusions were induced by intra-articularly administered carrageenin (0.3 ml, 1%), which rarely resulted in clinical lameness. The free radicals were generated in vitro by mixtures of iron and ethylene diamine tetra acetate (Fe/EDTA) or mixtures of hypoxanth...
[Biological and parasitic variations in horses infested and reinfested by Trichinella spiralis]. Seven mares were infected with 20,000 Trichinella spiralis larvae; 2 of them were reinfected 22 wk later with the same amount of larvae. The course of infection in horses was assessed by serology (ELISA), biochemistry (aldolase activity), parasitology and histopathology. In each animal, infection was followed by a significant rise in specific antibody titers culminating at 5-10 wk post-infection (pi) and decreasing thereafter. Reinfection was followed by a slight rise in antibody levels. Aldolase activity increased during the first infection, but was not modified by reinfection. The parasite b...
Ultrasonographic and quantitative histologic assessment of sequelae to testicular biopsy in stallions. A sample of testicular parenchymal tissue, approximately 2 x 7 x 7 mm, was aseptically removed from 1 testis in each of 9 stallions on day 0. Slight to moderate hemorrhage from the tunica albuginea was observed in 8 stallions, but bleeding from the parenchyma was detected in only 2 stallions. Stallions were castrated 27 days later. Normal development of granulation tissue was evident at the biopsy site, but hematomas were not observed. In situ measurement of the widths of the right and left testes, total scrotal width, and evaluation of testicular echogenicity during ultrasonography were varia...
Arachidonate metabolites in bronchoalveolar lavage fluid from horses with and without COPD. Arachidonate metabolites were measured in bronchoalveolar lavage fluid (BALF) from horses with (N = 4) and without (N = 7) chronic obstructive pulmonary disease (COPD). Prostaglandin (PG) D2, leukotriene (LT) B4 and LTC4 were present in highest concentrations in BALF from clinically normal horses. Concentrations of PGE2 and PGF were significantly higher in BALF from horses with COPD than in BALF from normal horses, but no differences were detected in thromboxane B2, 6-keto-PGF1 alpha, PGD2, LTB4 or LTC4.
Evaluation of two vaccines for the treatment of pythiosis insidiosi in horses. Two vaccines to treat phythiosis insidiosi in horses were evaluated in 71 Costa Rican horses between 1982 to 1988. One vaccine used a cell-mass (CMV) as antigen and the other a soluble concentrated antigen (SCAV). Both vaccines cured horses infected with Pythium insidiosum (p value approximately 14%). The age of lesions prior to vaccination was important in the response of the horses to immunotherapy. All horses with lesions 0.5 months or less in duration were cured regardless of the vaccine used. Horses with lesions two or more months old did not respond to either vaccine. The age of the hors...
Cytologic findings of tracheobronchial aspirates from 66 thoroughbred racehorses. Tracheobronchial aspirates obtained from 66 healthy Thoroughbred racehorses in training at the same track were examined. Twenty-seven percent of the horses had greater than 20% neutrophils in the aspirate. Eosinophils, mast cells, giant cells, and Curschmann's spirals of mucus were observed in 94, 83, 65, and 42% of the horses, respectively. Hemosiderophages were observed in 86% of the horses, half of which had previous confirmation of exercise-induced pulmonary hemorrhage. Although fungal elements were seen in 70% of the horses, bacteria were detected in only 3% of the horses. The authors con...
