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.
Hurst EW.The virus of equine encephalomyelitis (eastern strain) evokes in the horse, calf, sheep and dog an unusually intense encephalomyelitis characterized by acute primary degeneration of nerve cells, the appearance in neurons of the brain stem and elsewhere of nuclear inclusions resembling those in Borna disease and poliomyelitis, polymorphonuclear infiltration in the nervous tissues with early microglial proliferation, and perivascular cuffing with mononuclears and polymorphonuclears in varying proportions. The grey matter is affected more than the white. Lesions may be less marked in the striatum...
To compare ocular structures of Quarter Horses homozygous for hereditary equine regional dermal asthenia (HERDA) with those of Quarter Horses not affected by HERDA (control horses) and to determine the frequency of new corneal ulcers for horses with and without HERDA during a 4-year period. Methods: Cohort study of ocular structures and retrospective case series of horses with and without HERDA. Methods: The cohort portion of the study involved 10 Quarter Horses with HERDA and 10 Quarter Horses without HERDA; the retrospective case series involved 28 horses with HERDA and 291 horses without HE...
Unlike in Warmblood horses, aortic rupture is quite common in Friesian horses, in which a hereditary trait is suspected. The aortic connective tissue in affected Friesians shows histological changes such as medial necrosis, elastic fibre fragmentation, mucoid material accumulation and fibrosis with aberrant collagen morphology. However, ultrastructural examination of the collagen fibres of the mid-thoracic aorta has been inconclusive in further elucidating the pathogenesis of the disease. Objective: To assess several extracellular matrix (ECM) components biochemically in order to explore a pos...
Verstraete MH, Kuijpers F, Holl W, Norris J, van Heule M, Martin-Pelaez S, Heard C, Uribe-Salazar J, Armien A, Conley A, De Spiegelaere W....The endometrium is a hormonally responsive tissue that undergoes cyclic remodeling. Although endometrial organoids have been established in several species, detailed characterization remains limited. Here, we assessed the structural and molecular fidelity of equine endometrial organoids across reproductive cycle stages and during extended culture. Organoids were generated from biopsies collected during estrus and diestrus and analyzed using histology, immunohistochemistry, electron microscopy, and bulk- and single-cell RNA sequencing. Organoids formed polarized cystic structures composed of co...
Jasiński T, Borowska M, Juszczuk-Kubiak E, Turek B, Kaczorowski M, Bąk M, Żuk J, Domino M.Horses presenting with temporomandibular joint (TMJ) dysfunctions are often clinically evaluated for TMJ osteoarthritis (OA). Due to the unique characteristic of TMJ-related pain, the clinical diagnosis of equine TMJ OA is challenging; however, it may be supported by computer-aided tools incorporating biomarker data. This study aims to evaluate a machine learning-based approach to address a binary classification distinguishing healthy TMJs from TMJ OA. Among 50 equine cadaver heads, 82 TMJs were included and annotated as healthy or OA based on histological and computed tomography (CT) findings...
Carvalho RPR, Silva KDP, Ramirez-Lopez CJ, Guimarães-Ervilha LO, Lima TI, Teixeira-Soares CM, de Azevedo Viana AG, Ribeiro IM, Morais-Santos M....Infertility is a global concern in both humans and domestic animals, with male factors accounting for nearly half of all cases. Among male reproductive structures, the efferent ductules play a crucial but understudied role in fertility. These tubules connect the testis to the epididymis and are primarily responsible for luminal fluid reabsorption, a process essential for sperm concentration, maturation, and transport. This study aimed to provide a comparative morphological and histological characterization of the efferent ductules in four species-rats, bulls, stallions, and boars-focusing on r...
Faramarzi B, Lee D, Khamas W, Dong F.The distal sesamoidean impar ligament (DSIL) is a key component of the equine podotrochlear apparatus, yet its role in conditions such as caudal heel pain and navicular syndrome remains poorly understood. The objective of this study was to characterize the histological properties of the DSIL and evaluate how it is influenced by breed and age. Eighty-four cadaveric forelimb DSIL samples were collected from young, athletic Quarter horses (QHs), Thoroughbreds (TBs), and older, retired Quarter horses. Samples were stained and assessed for vessel size and count, number of nerve fascicles, and the r...
Forni G, Falomo ME, Casalini I, Isola M.Ossifying fibromas are uncommon in horses and complete surgical excision with premaxillectomy, maxillectomy or mandibulectomy is recommended. Piezosurgery has been previously used in equines only in one study. Objective: To report a case of ossifying fibroma treated with piezosurgery and to describe its follow-up. Methods: Clinical case report. Methods: A 4-year-old Zangersheide gelding was presented for a mass occupying the space of tooth 202. Histology confirmed the diagnosis of ossifying fibroma, which was removed by resection of soft tissues and a slice of the premaxilla with a piezotome. ...
Yang L, Song L, Lu Z, Yao X, Wang J, Zeng Y, Ren W, Luo P, Meng J.Adipose tissue functions not only as a primary energy reservoir but also as a metabolically active endocrine organ. However, the morphological and molecular differences among adipose depots from different anatomical sites in Yili horses remain unclear. This study aimed to compare the morphological characteristics and proteomic profiles of subcutaneous adipose tissue (SAT) and pericardial adipose tissue (PCAT). To this end, adipose tissue samples from 18 Yili horses were analyzed using hematoxylin and eosin (H&E) staining, while a subset of samples from 6 horses was subjected to proteomic a...
Zeldenrust EG, Carlton K, Jenkins EJ, Moré G, Nielsen MK, Pearl DL, Schott CR, Terier SM, Barta JR.Klossiella equi Baumann, 1946 (Apicomplexa: Coccidia) is a globally distributed adeleorinid parasite that infects the kidneys of equid hosts. Considered an uncommon parasite, when K. equi is detected, it is typically an incidental finding during histologic examination of the kidneys as part of routine necropsy. In the present study, kidney was collected opportunistically from 3 different equine populations: 1) routine necropsies at the Ontario Veterinary College (OVC; n = 48); 2) natural mortalities from the Sable Island wild horse herd (n = 25); and 3) routine necropsies of animals fr...
Pereira LMA, Schade J, Pereira LMA, Tocheto R, Cristo TG, Casagrande RA, Souza AF, Fonteque JH.This study aimed to determine the occurrence of swellings (lampas) in the rostral portion of the hard palate in young, adult, and elderly horses and to characterize them histologically. One hundred and twenty horses of different ages were evaluated by oral inspection. Horses were classified with lampas when the mucosa of the hard palate extended beyond the occlusal surface of the upper incisors and samples of palatal mucosa were collected. Ten other horses without rostral hard palate alterations, euthanized for unrelated causes, were included as the control group. Histological analysis include...
Romanucci M, Baghini S, Canonici F, Canonici P, Di Luzio Paparatti F, Marruchella G.Neck masses may represent a diagnostic challenge for equine veterinarians, since they may involve different structures with a similar clinical appearance. Whereas neck masses in foals mostly result from non-neoplastic conditions, including various congenital abnormalities, neoplastic cervical masses have been rarely documented. This report describes the unusual case of a rapidly growing neck cancer in a four-month-old colt, resulting in a fatal outcome. Gross and immunohistological findings were most consistent with a poorly differentiated thymic carcinoma with sarcomatoid features and multifo...
Su Y, Wen L, Jiang J, Wen M, Zeng Y, Meng J, Wang J, Ren W, Yao X.This study systematically elucidated the developmental characteristics and molecular regulatory mechanisms of the testis during the critical period of sexual maturation in Kazakh horses by combining histological observation of one- and two-year-old testicular tissues with transcriptomic sequencing. In the testes of one-year-old horses, no obvious lumen was observed, and the interior is mainly comprising supporting cells and spermatogonia on the basement membrane; in contrast, in the testes of two-year-old horses, the tubular lumen was complete with spermatogonia, spermatocytes, and spermatozoa...
