Copper and zinc status in adjuvant-arthritic rat: studies on blood, liver, kidneys, spleen and inflamed paws.

The status of copper and zinc in plasma, blood cells, kidneys, spleen and hind paws was evaluated in tail-injected adjuvant-arthritic rats, during both the asymptomatic (3 and 7 days after the inoculum) and symptomatic (14, 21 and 30 days after the inoculum) phases of the experimental disease. During the symptomatic phase, inflamed rats were studied divided into two groups on the basis of their arthritic scores (low-score L.S. and high-score H.S. arthritic rats). Copper (both in concentration and total amount) was found significantly increased in plasma, blood cells, liver, spleen and arthritic paws, whereas, in the kidneys, it was found to be lower than normal. Zinc was found to be remarkably increased in the liver. In blood, zinc was found to be decreased in plasma, but almost unchanged in the cellular fraction. Zinc total amount (but not concentration) was increased in the spleen, most likely because of a significant increase in spleen weight. As previously described in the case of acute inflammation, zinc concentration was found to be significantly decreased in arthritic paws, whereas the total amount of the metal present in these inflamed tissues was higher than normal. The status of copper and zinc may well differentiate L.S. from H.S. arthritic rats, especially during the latest phase of the experimental disease, and particularly because of a normalization of the considered parameters in the low-score group. Many of the changes observed in the status of both metals were seen prior the appearance of arthritis. The overall accumulation of copper and zinc which is induced in rat by the development of adjuvant arthritis, is suggested to further sustain the hypothesis of increased body requirements for both metals during inflammation.