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Topic:Histology
Histology in horses involves the microscopic examination of tissues to understand their structure and function. This field of study provides insights into the cellular composition and architecture of equine tissues, aiding in the diagnosis of diseases and the assessment of tissue health. Histological analysis is used to identify pathological changes, such as inflammation, neoplasia, or degenerative conditions, by examining tissue samples obtained through biopsies or necropsies. Common tissues studied in equine histology include skin, muscle, bone, and internal organs. This page compiles peer-reviewed research studies and scholarly articles that explore histological techniques, findings, and their applications in equine veterinary medicine.
Age-related changes in the testes of horses. Atrophy of seminiferous tubules and interstitial fibrosis are frequently observed in aged horses. Samples from 8 male Thoroughbreds, age 4-24 years, were subjected to histological, electron microscopical and immunohistochemical examination and statistical analysis. There were statistically significant increases in collagen fibres in the lamina propria of seminiferous tubules and testicular interstitium in 3 horses age 23 and 24 years compared with 5 horses age 4-20 years (P<0.001). Lamina propria surrounding atrophic tubules was thickened by an increase in collagen type IV and elastic fibre...
The distribution of intratubular dentine in equine incisors: a scanning electron microscopic study. The distribution of intratubular (peritubular) dentine was studied by scanning electron microscopy in 12 equine incisor teeth. High levels of intratubular dentine were found in the peripheral regions of the dentine. In these areas, a marked asymmetry occurred, as intratubular dentine was predominantly deposited onto the side of the dentinal tubular walls nearest to the dentino-enamel junction. The quantity and asymmetry of intratubular dentine were reduced towards the centre of the tooth. The significance of these variations in the amount and distribution of intratubular dentine between the di...
Early and long-term changes of equine skeletal muscle in response to endurance training and detraining. Twenty-four 4-year-old Andalusian (Spanish breed) stallions were used to examine the plasticity of myosin heavy chain (MHC) phenotype and the metabolic profile in horse skeletal muscle with long-term endurance-exercise training and detraining. Sixteen horses underwent a training programme based on aerobic exercises for 8 months. Afterwards, they were kept in paddocks for 3 months. The remaining eight horses were used as controls. Three gluteus medius muscle biopsy samples were removed at depths of 20, 40 and 60 mm from each horse before (month 0), during (month 3) and after (month 8) training,...
Segmental eosinophilic colitis: a review of 22 cases. Twenty-two horses with colic, referred to the University of Liverpool Equine Hospital (1992-1998), were found at laparotomy to have a partial obstruction of the large colon caused by a segmental mural lesion located in the left dorsal colon. The decision to take the horses to surgery was based on rectal examination findings of secondary impaction and mural oedema of the large colon and turbid peritoneal fluid containing large numbers of neutrophils obtained by paracentesis. The affected segment of colon showed oedema and serosal changes varying from erythema to well-defined necrosis. These pat...
[Diagnosis of stomach carcinoma in the horse]. In 10 horses, which were referred to the clinic with the suspicion of disorders of the gastrointestinal tract, gastroscopy revealed a gastric tumour. In ten cases the diagnosis of a squamous cell carcinoma was made on the basis of histology of biopsies or autopsy. The tumour always derived from the non-glandulary mucosa. The horses showed various clinical symptoms. All patients had a hypoalbuminemia and a hyperglobulinemia in the serum electrophoresis. This suggests that a gastric tumour can be suspected intra-vitam even without gastroscopy of the patient.
The dentinal structure of equine incisors: a light and scanning electron-microscopic study. This paper gives an anatomical overview of the dentinal structure in equine incisor teeth with special reference to the three-dimensional organization, the number and the diameter of the dentinal tubules. The spatial arrangement of equine dentine was examined by scanning electron microscopy of occlusal surfaces and longitudinally fractured teeth and by light microscopy of both decalcified and ground sections. The dentinal tubules of the peripherally situated primary dentine were directly continuous with those of the circumpulpal secondary dentine. The tubules had numerous side branches along t...
Histological and morphometrical studies on the mucosa of the equine guttural pouch (auditory tube diverticulum). The present study attempted to clarify the characteristics of the guttural pouch mucosa in equines and to evaluate its foreign substance clearance ability. The specimens were collected from nine regions (eight in the guttural pouch mucosa, and one in the nasopharynx mucosa). We first examined the pouch mucosa by light and electron microscopy. We then measured the frequency of goblet cells per 200 epithelial cells, the length of the cilia, the thickness of the epithelial cell layer and lamina propria and statistically analyzed the data. The guttural pouch mucosa consisted of stratified columnar...
Use of an extracorporeal circuit to evaluate effects of ischemia and reperfusion of the equine large colon. To determine efficacy of an extracorporeal circuit to maintain a segment of equine large colon for 3.5 hours and to evaluate the effect of low arterial flow on histologic and metabolic variables. Methods: Segments of large colon from 15 healthy adult horses. Methods: The pelvic flexure was surgically removed and maintained in an isolated circuit. In the control group, tissue was evaluated for 3.5 hours, whereas in the low-flow group, arterial flow was reduced to 20% of baseline for 40 minutes followed by 2 hours of reperfusion. Various metabolic and hemodynamic variables were evaluated at 30-m...
Detection of DNA in ancient bones using histochemical methods. We describe histochemical techniques for detecting DNA within the osteocytic lacunae of ancient bones. The bones examined were fragments of femurs from two human individuals found in the Pompeian C. I. Polybius house and fragments of metacarpals from two horses (Equus sp.) found in the Pompeian "Casti Amanti" house. Both buildings were buried by the 79 A. D. Vesuvius eruption. Fragments of femurs from a modern horse, a modern swine and a modern amphibian also were studied as controls. Some bone sections were stained with two different DNA-specific fluorochromes, 4'-'6-diamidino-2-phenylindole ...
A unique exocelom-like space during early pregnancy in the horse. The free allantois and allantochorion of conceptuses from 17 mares between 20 and 90 days of gestation were examined to determine the manner in which the associated mesodermal derivatives differentiated. It was found that a robust basement membrane developed under the allantoic endoderm, and that this basement membrane was partially isolated from the vascular layer of the allantois by a mesothelial layer and an exocelom-like space. The exocelom-like space persisted until approximately the stage of villous formation, and remnants of the space persisted over larger allantoic vessels even later. ...
Light and scanning electron microscopic studies of the nasal turbinates of the horse. The nasal turbinates of 5 young horses were studied by light and scanning electron-microscopy. Stratified cuboidal epithelium lined the rostral part of the dorsal and ventral nasal turbinates of the vestibular region. The polyangular microvillus cells of this region were separated by linear depressions. The mid and caudal parts of the dorsal and ventral nasal turbinates and the rostral part of the ethmoturbinates were lined by pseudostratified columnar ciliated respiratory epithelium. Numerous cilia with dilated blebs on the ciliated cells concealed adjacent non-ciliated supporting cells and g...
Pythiosis with bone lesions in a pregnant mare. A 9-year-old pregnant mare was referred for evaluation of a nonhealing wound of 8 weeks' duration on the lateral aspect of the left forelimb. A soft tissue mass encircled the proximal two thirds of the metacarpus; radiography revealed a moderate periosteal reaction affecting metacarpal bone i.v. Histologic and immunohistochemical examinations revealed eosinophilic granulomatous inflammation and Pythium sp in the soft tissues. The mare was treated for 12 days with antimicrobials, medicated wound dressings, debridement, and i.v. administration of sodium iodide; radiography revealed progression o...
Cyclical endometrial steroid hormone receptor expression and proliferation intensity in the mare. The aims of this study were to investigate the steroid hormone receptor expression and the proliferation intensity during the equine endometrial cycle by immunohistological methods, established for routine examination of formalin-fixed, paraplast-embedded specimens. Endometrial biopsy specimens were obtained during one cycle from 7 mares. In comparison with the blood steroid hormone levels the quantity and distribution of oestrogen (ER) and progesterone receptors (PR) and the proliferation marker Ki-67 antigen expression were investigated. Rising 17beta-oestradiol concentrations in preoestrus ...
Autologous morsellised bone grafting restores uncontained femoral bone defects in knee arthroplasty. An in vivo study in horses. The properties of impacted morsellised bone graft (MBG) in revision total knee arthroplasty (TKA) were studied in 12 horses. The left hind metatarsophalangeal joint was replaced by a human TKA. The horses were then randomly divided into graft and control groups. In the graft group, a unicondylar, lateral uncontained defect was created in the third metatarsal bone and reconstructed using autologous MBG before cementing the TKA. In the control group, a cemented TKA was implanted without the bone resection and grafting procedure. After four to eight months, the animals were killed and a biomechan...
Hepatoblastoma with erythrocytosis in a young female horse. A 2.5-year-old female Thoroughbred was examined because of lethargy, anorexia, and weight loss. Analysis of a CBC revealed erythrocytosis and an increase in PCV. Serum biochemical analysis revealed increases in activities of several hepatic enzymes. Ultrasonography revealed hepatomegaly and a heterogeneous appearance of the hepatic parenchyma. The horse did not improve despite supportive care, and it was euthanatized. Necropsy revealed numerous raised white to gray foci in the liver. Histologically, these foci consisted of neoplastic cells that resembled fetal hepatocytes, embryonal-type cells...
Squamous cell carcinoma of the urethral process in a horse with hemospermia and self-mutilation behavior. A 14-year-old Arabian stallion was examined because of acute hemospermia. The stallion was used in an artificial breeding program and had a 6-year history of low-grade hemospermia and a 4-year history of self-mutilation behavior. During previous examinations, minor irritation of the urethral process was identified as the source of the bleeding. Physical examination revealed a mucosal ulceration in the distal portion of the urethra. Histologic examination of a biopsy specimen from this area revealed low-grade squamous cell carcinoma. The urethral process was excised, and the hemospermia resolve...
Effect of topical rh-TGF-beta 1 on second intention wound healing in horses. To investigate the effects on wound healing of transforming growth factor-beta 1 as a topical treatment to full-thickness, excisional wounds of the distal limb of horses. Methods: A randomised block study using four horses, each with wounds assigned to four treatment groups. Methods: Four adult Standardbred geldings. Methods: Four, 4 cm2, full-thickness wounds were created on the dorsomedial and dorsolateral aspect of the metacarpus or metatarsus of each limb of four horses, giving a total of 64 wounds. For each limb, wounds were randomly assigned to four treatment groups: no treatment (contro...
Ultrasonographic tissue characterization of equine superficial digital flexor tendons by means of gray level statistics. To correlate quantitative analysis of ultrasonographic images of normal (injury-free) equine superficial digital flexor (SDF) tendons and equine SFD tendons that have pathologic changes with corresponding histologic sections. Methods: 4 SDF tendons, 2 of which had various stages of tissue integrity. The 2 ipsilateral tendons were used as points of reference. Methods: Tendons were mounted in a custom-made device that permitted sequential scanning, transversely and perpendicular to the tendon long axis. At precise steps of 0.5 mm, transverse ultrasonographic images were collected. Subsequently, ...
The effect of compacted cancellous bone grafting on the healing of subchondral bone defects of the medial femoral condyle in horses. To compare the quality of second-intention healing and that of compacting sternally harvested cancellous bone into subchondral bone defects of the medial femoral condyle in horses. Methods: A controlled experiment using a surgical technique that minimizes soft tissue trauma, customized for consistency among horses. Methods: Ten horses, aged 2 to 5 years, free of hindlimb lameness and with radiographically normal stifles. Methods: After a 12.7-mm-diameter x 19-mm-deep defect was created into randomly selected medial femoral condyles, bone and cartilage healing was evaluated over a 6-month perio...
Characterization of cellular and vascular changes in equine follicles during hCG-induced ovulation. In contrast to other species, the histology of the equine follicle during ovulation has not been described. Preovulatory follicles were isolated during oestrus at 0, 12, 24, 30, 33, 36 and 39 h (n = 5-6 follicles per time point) after an ovulatory dose of hCG to characterize the cellular and vascular changes associated with ovulation in mares. Pieces of follicle wall were formalin-fixed and processed for light microscopy to evaluate the general follicular morphology and quantify selected parameters. Marked changes were observed in the histology of equine follicles in the hours before ovulation...
Quantitative histological analysis of equine embryos at exactly 156 and 168 h after ovulation. Equine embryos were collected at exactly 156 +/- 0.5 (n=8) and 168 +/- 0.5 h (n=11) after ovulation. The embryos were fixed in glutaraldehyde, sectioned serially and observed using light microscopy. In the 156 h group, all embryos were early blastocysts except for one, which was a morula. The morula and one early blastocyst had no capsule. The capsules of the other embryos were thin. The mean +/- SD total number of cells was 275 +/- 105 (range 117-417). The mean +/- SD proportions of mitotic and pycnotic cells were 2.5 +/- 1.2 and 1.1 +/- 1.8%, respectively, and there were no differences betwe...
Development of equine endometrial glands from fetal life to ovarian cyclicity. Branched tubular endometrial glands are key features of the uterine lining in mares. The epithelium in the neck regions of the glands is similar to that lining the lumen of the uterus, whereas the epithelium in the deeper, coiled portions of the glands secretes protein rich histotrophe or 'uterine milk' during dioestrus and pregnancy. The present study was performed to characterize endometrial histology in perinatal and peripubertal fillies and to investigate the influences of specific steroid treatments on endometrial gland development in the prepubertal period. Uteri obtained from equine fet...
Possible role of autoimmunity to spermatozoa in idiopathic infertility of stallions. Testicular degeneration is a major cause of subfertility in stallions, although an aetiological diagnosis cannot be made in most cases. In the present study, autoimmune testicular degeneration was induced and evaluated in stallions by immunizing stallions with their own spermatozoa mixed with an adjuvant. The factors evaluated included changes in semen quality and testicular histology. A large decrease in sperm number and quality was observed in response to sperm autoantigens. An ELISA test specific for antisperm antibodies was developed which enabled antibody titres in serum, seminal plasma a...
Mucus production by endometrium of reproductively healthy mares and mares with delayed uterine clearance. The aims of this study were to compare various staining and fixation techniques for endometrial biopsy samples and, thus, to investigate the mucociliary apparatus in endometrium from reproductively healthy mares and mares with delayed uterine clearance. Endometrial samples were collected from the left and right uterine horns of reproductively healthy mares (n=5) and mares with delayed uterine clearance (n=4) during anoestrus, transition, oestrus and dioestrus. Each sample of endometrium was fixed in either Bouin's fixative or formalin, and stained with alcian blue (pH 1.0 or 2.5), periodic aci...
Relationship between the degree of endometrial periglandular fibrosis and the presence of angiotensin-converting enzyme in the equine endometrium. Endometrial periglandular fibrosis (EPF) has been proposed as a possible aetiology for equine embryonic and fetal loss. However, the pathophysiology of EPF is not well understood. Angiotensin-converting enzyme (ACE) is found in macrophages, endothelium (during angiogenesis) and myofibroblasts at sites of fibrosis in the heart, kidneys, liver and skin in several species. An increase in local tissue ACE-binding activity appears to be a critical event in the initiation and progression of fibrosis in these tissues. The aim of this study was to investigate the correlation between ACE activity in th...
Simultaneous exocrine and endocrine secretion: trophoblast and glands of the endometrial cups. Invasion of trophoblast cells of the chorionic girdle into the endometrium and their subsequent dependence as endometrial cup cells on the maternal vascular system are unique features of equine gestation. This study of exocrine secretion by the endometrial glands and endocrine secretion by the cup cells was initiated to examine the relationships between and the effects of two disparate epithelial cell types sharing the endometrium. Endometrial cups were examined from day 36 to day 83 of gestation by light and electron microscopy, and immunohistochemical and lectin analysis. As the cup cells in...
Encephalopathy with idiopathic hyperammonaemia and Alzheimer type II astrocytes in equidae. In 3 mature female horses of varying breeds, episodes of colic and depression for 14 days preceded an encephalopathic disorder with maniacal behaviour, anxiety, profuse sweating and, in one case, terminal opisthotonus. Blood ammonia levels were elevated approximately 10-fold. At necropsy, there were gastrointestinal serosal and mesenteric haemorrhages. Histologically, all 3 cases revealed diffuse Alzheimer type II astrocytes in the cerebral grey matter. Alzheimer type II astrocytes were glial fibrillary acidic protein (GFAP) negative or only weakly positive, weakly S-100 positive, and vimentin...
The use of compound 48/80 as a positive control in equine intradermal allergy testing. The macroscopic and microscopic effects following the intradermal injection of the mast cell degranulator compound 48/80 were investigated in horses. It was found that a 1000 μg mL-1 solution of compound 48/80 could be used as an alternative to histamine as a positive control in equine intradermal allergy tests. An inflammatory cell infiltration was noted on histological examination, following compound 48/80 injection. This inflammatory cell pattern was similar to that noted for Type-I hypersensitivity.
Hepatic sarcocystosis in a horse. Hepatic sarcocystosis was diagnosed in a horse in association with refractory bacterial osteomyelitis and plasma cell tumor of the maxilla and hepatic salmonellosis. Gross lesions included pleural, pericardial, and peritoneal effusions, hepatomegaly, gastric ulceration, colonic edema, and proliferative tissues filling 2 maxillary dental alveoli. Histologically, liver was characterized by severe suppurative, necrotizing, periportal hepatitis, and severe periacinar necrosis. Hepatocytes frequently contained protozoal schizonts in various stages of development. In mature schizonts, merozoites wer...
