title: Intranasal Location and Immunohistochemical Characterization of the Equine Olfactory Epithelium.
abstract: The olfactory epithelium (OE) is the only body site where neurons contact directly the environment and are therefore exposed to a broad variation of substances and insults. It can serve as portal of entry for neurotropic viruses which spread via the olfactory pathway to the central nervous system. For horses, it has been proposed and concluded mainly from rodent studies that different viruses, e.g., Borna disease virus, equine herpesvirus 1 (EHV-1), hendra virus, influenza virus, rabies virus, vesicular stomatitis virus can use this route. However, little is yet known about cytoarchitecture, protein expression and the intranasal location of the equine OE. Revealing differences in cytoarchitecture or protein expression pattern in comparison to rodents, canines, or humans might help to explain varying susceptibility to certain intranasal virus infections. On the other hand, disclosing similarities especially between rodents and other species, e.g., horses would help to underscore transferability of rodent models. Analysis of the complete noses of five adult horses revealed that in the equine OE two epithelial subtypes with distinct marker expression exist, designated astypes aandbwhich resemble those previously described in dogs. Detailed statistical analysis was carried out to confirm the results obtained on the descriptive level. The equine OE was predominantly located in caudodorsal areas of the nasal turbinates with a significant decline in rostroventral direction, especially fortype a. Immunohistochemically, olfactory marker protein and doublecortin (DCX) expression was found in more cells of OEtype a, whereas expression of proliferating cell nuclear antigen and tropomyosin receptor kinase A was present in more cells oftype b. Accordingly,type aresembles the mature epithelium, in contrast to the more juveniletype b. Protein expression profile was comparable to canine and rodent OE but equinetypes aandbwere located differently within the nose and revealed differences in its cytoarchitecture when compared to canine OE. Equine OEtype aclosely resembles rat OE. Whether the observed differences contribute to species-specific susceptibility to intranasal insults such as virus infections has to be further investigated.
authors: Institute of Veterinary Pathology, Faculty of Veterinary Medicine, Justus Liebig University GiessenGiessen, Germany; Institute of Virology, Philipps University MarburgMarburg, Germany.
authors: Alexandra
authors: A
authors: Kupke
authors: Small Animal Clinic c/o Institute of Veterinary Anatomy, Histology and Embryology, Department of Veterinary Clinical Sciences, Justus Liebig University Giessen Giessen, Germany.
authors: Sabine
authors: S
authors: Wenisch
authors: Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus Liebig University Giessen Giessen, Germany.
authors: Klaus
authors: K
authors: Failing
authors: Institute of Veterinary Pathology, Faculty of Veterinary Medicine, Justus Liebig University Giessen Giessen, Germany.
authors: Christiane
authors: C
authors: Herden
keywords: horse; immunohistochemistry; olfactory epithelium; statistical analysis; subtypes