Induction of alopecia areata in C3H/HeJ mice using polyinosinic-polycytidylic acid (poly[I:C]) and interferon-gamma

Alopecia areata (AA) is a chronic, relapsing hair-loss disorder that is considered to be a T-cell-mediated autoimmune disease. Several animal models for AA have been created to investigate the pathophysiology and screen for effective therapeutic targets. As C3H/HeJ mice develop AA spontaneously in a low frequency, a novel animal model is needed to establish an AA-like condition faster and more conveniently. In this study, we present a novel non-invasive AA rodent model that avoids skin or lymph-node cell transfer. We simply injected C3H/HeJ mice subcutaneously with interferon-gamma (IFNγ) along with polyinosinic:polycytidylic acid (poly[I:C]), a synthetic dsRNA, to initiate innate immunity via inflammasome activation. Approximately 80% of the IFNγ and poly(I:C) co-injected mice showed patchy AA lesions after 8 weeks. None of the mice displayed hair loss in the IFNγ or poly(I:C) solely injection group. Immunohistochemical staining of the AA lesions revealed increased infiltration of CD4(+) and CD8(+) cells infiltration around the hair follicles. IFNγ and poly(I:C) increased the expression of NLRP3, IL-1β, CXCL9, CXCL10, and CXCL11 in mouse skin. Taken together, these findings indicate a shorter and more convenient means of AA animal model induction and demonstrate that inflammasome-activated innate immunity is important in AA pathogenesis.