Study of the behaviour of lesional and nonlesional skin of canine recurrent flank alopecia transplanted to athymic nude mice

Background: Recurrent flank alopecia is a clinically well-described skin disorder in dogs. The pathomechanism of the disease is difficult to study because it undergoes spontaneous regression. Hypothesis/Objectives: To study the behaviour of xenografts in mice in order to assess the feasibility of a reproducible experimental model and to investigate local or systemic causes of canine recurrent flank alopecia (cRFA). Methods: Skin biopsies were taken from lesional and nonlesional skin of two client-owned dogs with cRFA and grafted onto five athymic mice from a research facility. The lesional skin and xenografted skin were evaluated histologically on day0 and day30, respectively. Results: Transplanted lesional and nonlesional canine skin regrew hair within 30days, while the donor dogs were still alopecic in the lesional areas on day30 after the skin biopsy procedure. Graft rejection was evidenced histologically in two xenografted athymic mice. Lesional hyperpigmentation disappeared in the athymic mice. Conclusions and clinical importance: This study showed that hair follicles from dogs with cRFA quickly regenerated and regrew hair once grafted onto the mice. Our data indicate that the pathogenesis of cRFA is likely to be mediated by systemic rather than local factors. While this xenograft approach might not be of much value for the study of cRFA, it has potential value for the study of other causes of canine alopecia due to systemic factors