TGF-β1 Expression by Proliferated Keratinocytes in the Skin of E-Irradiated Mice

In this study, we established a radiodermatitis animal model and investigated the change in immune cell proportions in the secondary lymphoid organs. The cells responsible for the increased transforming growth factor-β1 (TGF-β1) and interleukin-10 (IL-10) production in the lesions following irradiation were also investigated. The radiodermatitis model was constructed by locally exposing the posterior dorsal region of hairless-1 (HR-1) mice to 10 Gy electron (E)-ray/day for six consecutive days. The change in immune cell proportions was analyzed by FACS. Immunohistochemistry was carried out to detect the expression of cytokines and cell-specific markers in the skin. The proportions of antigen-presenting cells, T cells, and B cells in the lymph nodes and spleen were affected by E-irradiation. After irradiation, TGF-β1 and IL-17 were co-localized in the papillary region of the dermis with keratin-14 (K-14)-positive cells rather than with regulatory T cells (Treg). IL-10 was not co-stained with Treg, T helper 17 (Th17) cells, dendritic cells, or macrophages. Our data indicate that TGF-β1 is over-expressed mainly by proliferated keratinocytes in the lesions of a radiodermatitis animal model.