title: Development and characterization of an equine skin-equivalent model.
abstract: BACKGROUND
  There is increasing interest in the biological and pathological study of equine skin owing to the high prevalence of cutaneous diseases in horses. However, knowledge of equine skin cell biology and cultures is limited by the low number of in vitro studies in the literature.
  
  
  OBJECTIVE
  The objective of the study was to develop and characterize an in vitro equine skin equivalent.
  
  
  METHODS
  Cultures of pure equine keratinocytes and dermal fibroblasts were obtained by enzymatic digestion of skin biopsies. Fibroblasts were embedded into type I collagen matrices to obtain dermal scaffolds, the surface of which was seeded with keratinocytes. The three-dimensional cultures were exposed to the air-liquid interface to enable epidermal stratification.
  
  
  RESULTS
  After 14 days in air-exposed conditions, histological analysis showed that keratinocytes underwent differentiation into a multilayered epidermis. Immunohistochemical studies revealed the expression of epidermal cytokeratin in keratinocytes, whereas vimentin was expressed in dermal fibroblasts, as expected in equine skin. Immunostaining of Ki67 showed proliferative keratinocytes in the stratum basale. A continuous basement membrane at the dermo-epidermal junction was also detected immunohistochemically through the expression of its major components (type IV collagen and laminin 5). Ultrastructural analysis by electron microscopy showed desmosomes located among keratinocytes in all layers and hemidesmosomes among the basal keratinocytes and lamina densa.
  
  
  CONCLUSIONS
  This study reports, for the first time, the development of an in vitro equine skin-equivalent model that resembles equine skin morphologically, immunohistochemically and ultrastructurally.
authors.affiliation: UNIVET, Edifici Astrolabio, Avinguda Cerdanyola 92, 08172, Sant Cugat del Vallès, Barcelona, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Cerrato
authors.forename: Laura
authors.initials: L
authors.lastname: Ramió-Lluch
authors.forename: Pilar
authors.initials: P
authors.lastname: Brazís
authors.forename: Rosa Maria
authors.initials: RM
authors.lastname: Rabanal
authors.forename: Dolors
authors.initials: D
authors.lastname: Fondevila
authors.forename: Anna
authors.initials: A
authors.lastname: Puigdemont
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000662:veterinary; D003094:Collagen; D005347:Fibroblasts / Q000502:physiology; D006736:Horses / Q000033:anatomy & histology*; D015603:Keratinocytes / Q000502:physiology; D012867:Skin / Q000033:anatomy & histology* / Q000648:ultrastructure
chemical_list: D003094:Collagen