Effect of free radical scavengers on superoxide dismutase (SOD) enzyme in patients with alcoholic cirrhosis.

The in vitro and in vivo effects of three hepatoprotective antioxidants (silymarin, (+)cyanidanol-3 and 4-amino-5-imidazole-carboxamide-phosphate) on the expression and activity of superoxide dismutase (SOD) enzyme were studied in erythrocytes and lymphocytes from patients with alcoholic cirrhosis. In vitro incubation with the drugs in a concentration corresponding to the usual therapeutic dosage markedly increased (i) the SOD expression of lymphocytes as measured by flow-cytofluorimetry following staining with monoclonal anti-Cu, Zn-SOD-antibody and FITC-conjugated anti-mouse Ig, as well as (ii) erythrocyte and lymphocyte SOD activities. In vivo treatment also restored the originally low SOD activity and expression of the patients' lymphocytes and erythrocytes. The data indirectly suggest that antioxidant activity might be one of the important factors in the hepatoprotective action of these agents.