Effects of dietary copper depletion on acute and delayed inflammatory responses in mice

Acute and delayed hypersensitivity reactions were compared in mice fed diets low in copper (less than 20 mumol copper kg-1) or adequate (more than 300 mumol copper kg-1) for seven to nine weeks after weaning. In the copper depleted animals there was a significant enhancement (P less than 0.01) of histamine-induced paw oedema measured 15 minutes after challenge. The variance of responses within the two dietary groups was similar. Delayed contact hypersensitivity reactions to oxozalone were also significantly increased (P less than 0.01) in the deficient mice. In this study there were some signs of differences in variance heterogeneity but they were statistically insignificant. Delayed-type hypersensitivity to sheep erythrocytes was similarly but less markedly (P less than 0.05) affected. Group differences just failed to reach statistical significance after logarithmic transformation (P less than 0.07) or non-parametric analysis (P less than 0.06). At challenge, the copper deficient mice had a significant (P less than 0.05) plasma hypercholesterolaemia. A few individuals also showed signs of spleen enlargement and mild haemoglobinaemia but otherwise the animals appeared clinically normal and were similar in weight to the controls. Plasma (P less than 0.001), erythrocyte (P less than 0.01) and liver (P less than 0.01) copper concentrations were significantly reduced in the copper-depressed mice, although the concentrations of copper and zinc in the spleen were increased (P less than 0.05) in the same group. Whole blood superoxide dismutase activity was also significantly decreased (P less than 0.01) but erythrocyte glutathione peroxidase activities were similar in both groups, as were blood and liver zinc concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)