Zinc effects on nickel dermatitis in the guinea pig.

Prevention of NiSO4 induced allergic contact dermatitis (ACD) using ZnSO4 in drinking water was studied in a guinea pig model. Without ZnSO4 interventions, nickel (Ni)-exposure resulted in significantly higher (p less than 0.05) stimulation indices (SIs) as compared to non-exposed controls, using NiSO4 as an allergen in the lymphocyte transformation test (LTT). Oral intake of ZnSO4 at both 250 micrograms/ml double-distilled deionized water (DDD) and 500 micrograms/ml DDD resulted in lower SIs than those of control guinea pigs drinking only DDD; the 250 micrograms/ml group had significantly lower SIs (p = 0.025) than controls. There was no significant correlation between intradermal test responses and the SI values of individual guinea pigs exposed to NiSO4. Mean zinc (Zn) concentrations in skin and in whole blood were not statistically different between the NiSO4 exposed control and Zn supplemented groups, nor between Ni-sensitive and non-sensitive animals within groups. The rôle of Zn homeostasis, rôle of the Langerhans cell, effect of Zn supplementation on Ni ACD in other species, and possible blocking effects of other metals should be investigated in future studies.