Cigarette Smoke Condensate Causes a Decrease of the Gene Expression of Cu–Zn Superoxide Dismutase, Mn Superoxide Dismutase, Glutathione Peroxidase, Catalase, and Free Radical-Induced Cell Injury in SH-SY5Y Human Neuroblastoma Cells

Cigarette smoking condensate (CSC) contains oxidant compounds able to generate superoxide. The aim of the present study was to investigate the effect of the exposure to CSC on: (1) free radical production, (2) the gene expression of the antioxidant enzymes Cu–Zn superoxide dismutase (SOD1), Mn superoxide dismutase (SOD2), Glutathione Peroxidase (GPx), and catalase (CAT), and (3) cell survival in human neuroblastoma SH-SY5Y cells. The results showed that exposure (24 h) to different concentrations (10–150 μg/ml) of CSC caused a dose dependent cell injury that was coupled to the maximal increase of free radical production. These events were prevented by the addition to the incubation medium of the scavenger Vitamin E (50 μM). Furthermore, CSC exposure caused a reduction of the gene expression of the antioxidant enzymes SOD1, SOD2, GPx, and CAT that was counteracted by Vitamin E (50 μM). These results suggest that CSC exposure can induce a free radical overcharge that may be responsible for the inhibition of antioxidant enzymes expression and cell injury in SH-SY5Y human neuroblastoma cells. In fact the scavenger vitamin E can block both cell injury and inhibition of SOD1, SOD2, GPx, and CAT induced by CSC exposure.