Background: Zinc is one of the essential dietary factors and zinc deficiency diminishes the immune system. However, the mechanisms by which zinc deficiency affects the immune system are not fully understood.
Objective: We analyzed the mechanisms of zinc deficiency affecting the allergic response using a DS-Nh mouse model of atopic dermatitis.
Methods: Male DS-Nh mice were fed a zinc deficient diet for 4 weeks. We measured transepidermal water loss (TEWL) and epidermal moisture level, assessed the skin eruption score, and examined the frequency of lymphocyte subpopulation in spleen and thymus by flow cytometry. The suppressive effect of CD25+CD4+ T cells was analyzed in vitro. The amount of cytokines produced by the spleen cells and the serum IgE levels were measured by ELISA.
Results: In DS-Nh mice fed the zinc deficient diet, skin eruptions were exacerbated and serum IgE levels and number of S. aureus on the skin surface was increased. IFN-gamma and IL-13 production by spleen cells was increased. The number of CD25+CD4+ T cells in spleen was significantly decreased, while the percentage of Foxp3 positive cells in the CD25+CD4+ T cells was comparable to those of the controls. CD25+CD4+ T cells from mice fed the zinc deficient diet maintained a suppressive function compared with those from the controls.
Conclusion: These findings indicate that zinc deficiency influences the skin barrier system and immune system, and suggests that zinc deficiency acts as an exacerbation factor of atopic dermatitis.