Deterioration of dry skin in arthritis model mice via stress-induced changes in immune cells in the thymus and spleen

Skin dryness is a characteristic of rheumatoid arthritis model mice. We previously reported that the stress hormone glucocorticoid (i.e., corticosterone) is related to the induction of dry skin in arthritic mice. However, the mechanism through which stress induces dry skin in these mice is still unclear. Therefore, in this study, we examined the relationship between stress and induction of dry skin in arthritic mice. Physical stress load in mice with DBA/1JJmsSlc collagen-induced arthritis was treated with water immersion stress, and transepidermal water loss and the expression of markers associated with allergic reactions and inflammation was evaluated. Deterioration of skin dryness was observed in stressed arthritic mice compared with that in unstressed arthritic mice. Moreover, plasma levels of interleukin-6 and corticosterone were increased in stressed arthritic mice compared with those in unstressed arthritic mice. We also observed decreased regulatory T cell numbers and increased T helper type 2 cell numbers in the thymus of stressed arthritic mice compared with those in unstressed arthritic mice. These results suggested that abnormalities in the immune system were related to deterioration of dry skin in stressed arthritic mice. Thus, reduction of stress may prevent deterioration of dry skin in mice with arthritis.