Free radical processes are proposed to play a crucial role in the deve
lopment of procainamide adverse effects. Therefore, selenium, as a pot
ent antioxidant, may modified procainamide toxicity. To test this hypo
thesis plasma and Liver thiobarbituric acid-reacting substances (TBARS
), plasma antioxidant activity (AOA), erythrocyte and liver superoxide
dismutase (SOD), catalase, as well as selenium-dependent glutathione
peroxidase (Se-GPX) were determined in the following four groups of ra
ts: selenium-treated (Se), procainamide-treated (P), procainamide and
selenium-treated (P + Se), and control (C). Morphological studies of l
eukocytes [tested for lupus erythematosus (LE) cells] and liver were a
lso made. Atypical, i.e. enlarged and swollen, leukocytes resulting fr
om procainamide and selenium treatment were observed. These changes we
re found in four out of five rats in the Se group, eight out of ten in
the P group, and in seven out of ten in the P + Se group. LE-like cel
ls were observed in two rats in the P + Se group. A statistically sign
ificant decrease in plasma and Liver TBARS by 20% and 36%, respectivel
y, increased activity of SOD by 20%, catalase by 48% and Se-GPX by 15%
in erythrocytes, and decreased activity of liver SOD by 17% and catal
ase by 22% were found in the P + Se group as compared to the P group.
These results indicated that selenium exerted antioxidant effects on t
he procainamide-treated rats. However, selenium did not prevent the de
velopment of disturbances in leukocyte morphology, on the contrary, it
possibly promoted the conversion of leukocytes to LE cells.