Enzymatic and non-enzymatic antioxidant status in stage (III) human oral squamous cell carcinoma and treated with radical radio therapy: Influence of selenium supplementation

Background: Oxidative stress is implicated in oral carcinogenesis and has been found to be aggravated during radiotherapy. A great deal of attention has been focused on the possible therapeutic implications of selenium as a potent antioxidant. We determined whether selenium supplementation to radiation treated oral cancer patients render improvement in the antioxidant status against oxidative stress. Method: Blood samples were collected from stage (111) oral cancer patients before initiating radiotherapy (Group B) (n=63) and this group is bifurcated into Group C-patients given radiotherapy alone (n=27) and Group D-patients given radiotherapy and supplemented with selenium (400 mu g/day for 6 months) (n=36). Both Group C and D were followed up for 6 months. We evaluated the plasma selenium concentration, nonenzymatic system including GSH, vitamins E, C, A and ceruloplasmin and enzymatic antioxidant system including superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase. Results: The concentrations of selenium, all non-enzymatic antioxidants and the activities of enzymatic antioxidants were found to be lowered in oral cancer patients (Group B), compared to normal (Group A) (p < 0.05). Similar decrease in the concentration of selenium and antioxidants status was observed in radiotherapy group (Group C) (p < 0.05). On the contrary, selenium group (Group D) showed marked increase in the concentrations of selenium and antioxidant status at 6 months compared to radiation group (Group C) (p < 0.05). Conclusion: The observed result represents the antioxidant property of selenium through the improvement of antioxidant defense system. Selenium supplementation could be of great interest in protecting cells against oxidative stress. (c) 2006 Elsevier B.V. All rights reserved.