Evaluation of oxidative stress and pro-inflammatory cytokines in occupationally cadmium exposed workers

Cadmium (Cd) exposure in environmental and occupational settings is a major public health concern. Cd exposure is associated with the production of free radicle and reactive oxygen species. The aim of the present study is to evaluate the effect of occupational exposure to Cd on oxidative stress and pro-inflammatory biomarkers in the workers.

100 occupationally exposed individuals working in the metal handicraft industry and welding industry were recruited from the industrial area of Jodhpur, Rajasthan. Blood Cd levels were estimated using atomic absorption spectroscopy. Serum Total Antioxidant Capacity (TAC), Catalase (CAT), Superoxide Dismutase (SOD), and Malondialdehyde (MDA) levels were measured by colorimetric method to assess oxidative status and serum IL-6 and TNF-α were measured by ELISA to assess inflammatory status.

The median Cd levels in the study population was 2.40μg/L, with welders having significantly higher Cd levels than metal handicraft workers. Among the oxidative stress markers, TAC and CAT were significantly lower, while MDA was significantly higher in subjects with high Cd levels. The Cd levels showed a significant negative and positive correlation with TAC and MDA, respectively. IL- 6 and TNF-α did not show a significant difference between the study groups, but both had an inverse correlation with antioxidant enzymes.

Occupational exposure to even low levels of Cd may result in oxidative stress in workers primarily via decrease in antioxidant enzymes and increasing lipid peroxidation. Increased oxidative stress in turn may result in immune cell activation which may result in increased concentration of pro-inflammatory cytokine in the exposed workers.