The Relationship between Copper & Zinc Concentration and Free Radical Markers in Copper Industry Workers

Introduction: Copper and zinc play a key role in oxidative reactions and in vivo studies have shown their different effects. In this study we examined the influence of exposure to copper and zinc on catalase and superoxide dismutase (SOD) activities in erythrocytes, total serum antioxidant capacity and malondiadehyde (MDA) production of copper industry workers. Methods: In the present study, 70 workers in a Copper Industry and 70 healthy controls with the age range of 35-55 years were studied. The catalase assay and SOD activity in RBC lysate and total antioxidant were measured by spectrophotometric methods. Using thiobarbitoric acid reaction, MDA concentration was determined. Results: The results showed a higher copper and zinc concentration in serum of worker group (113.8±2.2 & 148.3±3.2µg/L respectively, P<0.001) in comparison with the control group (104.5±1.5 & 107.7±2µg/L respectively). Serum catalase and SOD activities in RBC were higher in workers (7621.7±199.3 & 1489.5±12.3µ/l) than in the control group (7049.1±157.4 & 1421.7±11.1 µ/l respectively, P<0.05, for SOD only). Serum total antioxidant was significantly higher in workers than controls (1.6±0.03 vs. 1.4±0.01) and it was the same for MDA concentration (245.5±3.7nmol/gHb in the worker group compared to 205±3.2nmol/gHb in the control group). No correlation were found between copper and zinc concentrations and the other factors (P>0.05). Conclusion: These results suggest that occupational exposure to copper and zinc induces oxidative stress followed by anti oxidative defense system