Effects of Gamma-Tocopherol (GT) Supplementation on Vitamin E Concentration in Cigarette Smoke (CS) Exposed Mice

ABSTRACT

Cigarette smoke (CS) induces oxidative and nitrosative stress to the respiratory tract (RT) via both oxidants contained in CS and by CS-induced activation of RT inflammatory-immune pro-oxidant processes. CS exposure has been associated with reduced levels of plasma micronutrient antioxidants, in part due to an increased utilization and turnover of alpha-tocopherol (AT). It has been suggested that gamma-tocopherol (GT) may have an expanded spectrum of antioxidant activation compared to alpha-tocopherol (AT). In order to investigate effects of high GT supplementation as compared to AT, C57 BL/6 mice were fed control AT (35 mg/kg diet) or high GT (1,000 mg/kg diet) diet for 8-10 weeks and then exposed to 60 mg/m3 CS, 6 hr/day for 3 days. AT and GT levels and their metabolites were measured at endpoints. High GT supplementation significantly reduced AT levels in plasma, liver and lung compared to AT. CS increased levels of AT and GT in plasma and lung of control AT group but decreased GT levels in lung of high GT supplemented group. Moreover, CS significantly decreased GT metabolite, gamma-CEHC. The results suggest that high GT supplementation have selective modulation of concentrations of vitamin E and its metabolite in plasma and lung but not in liver against in vivo CS exposure.