Trace element status and inflammation parameters during chronic indomethacin treatment in adjuvant arthritic rats

Oral indomethacin administration (2 mg/kg/d) was investigated in rats with adjuvant arthritis up to a period of 5 wk. Baseline low serum zinc levels in arthritic rats increased rapidly from the first week of indomethacin treatment (started 1 or 2 wk after disease induction), whereas baseline high serum copper decreased after 1-2 wk. After 3-4 wk of treatment, serum zinc levels returned to control values, but serum copper was somewhat higher in arthritic animals having received indomethacin 2 wk after disease induction than in controls. Clinical indices of inflammation simultaneously improved to reach control values at the end of the trial. Biological indicators of inflammation also improved, but did not reach control levels. Serum zinc correlated negatively with plasma fibrinogen (r = -0.69, p < 0.0005) and serum copper correlated positively with serum ceruloplasmin (r = 0.92, p < 0.0005) both in indomethacin-treated and untreated arthritic rats. Contrary to long-term glucocorticoid administration that was previously reported to maintain or aggravate hypozincemia, indomethacin treatment normalized perturbed zinc and copper status in arthritic animals.