Suppressive Effects of Mesenchymal Stem Cells in Adipose Tissue on Allergic Contact Dermatitis

BACKGROUND Allergic contact dermatitis (ACD), which is accelerated by interferon (IFN)-γ and suppressed by interleukin (IL)-10 as regulators, is generally self-limited after removal of the contact allergen. Adipose tissue-derived multipotent mesenchymal stem cells (ASCs) potentially exert immunomodulatory effects. Considering that subcutaneous adipose tissue is located close to the site of ACD and includes mesenchymal stem cells (MSCs), the MSCs in adipose tissue could contribute to the self-limiting course of ACD. OBJECTIVE The aims of the present study were to elucidate the effects of MSCs in adipose tissue on ACD and to examine any cytokine-mediated mechanisms involved. METHODS Ear thickness in a C57BL/6 mouse model of ACD using contact hypersensitivity (CHS) elicited by 2,4,6-trinitro-1-chlorobenzene was evaluated as a marker of inflammation level. Five and nine mice were injected with ASCs and phosphate-buffered saline (PBS), respectively. After ASC or PBS injection, real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed. RESULTS Histology showed that CHS was self-limited and ear thickness was suppressed by ASCs in a dose-dependent manner. IFN-γ expression in the elicited skin site and regional lymph nodes was significantly lower in ASC-treated mice than in control mice. IL-10 expression did not differ between treated and control mice. The suppressive effects of ASCs on CHS response did not differ between IL-10 knock-out C57BL/6 mice and wild-type mice. CONCLUSION The present findings suggest that MSCs in adipose tissue may contribute to the self-limiting course of ACD through decreased expression of IFN-γ, but not through increased expression of IL-10.