Differential effects of α- and γ-tocopherol on low-density lipoprotein oxidation, superoxide activity, platelet aggregation and arterial thrombogenesis

Abstract OBJECTIVES This study was designed to examine the differential effects of α- and γ-tocopherol on parameters of oxidation-antioxidation and thrombogenesis. BACKGROUND Experimental studies have shown that antioxidants, such as vitamin E (α-tocopherol), improve atherosclerotic plaque stability and vasomotor function, and decrease platelet aggregation and tendency to thrombus formation. METHODS Sprague Dawley rats were fed chow mixed with α- or γ-tocopherol (100 mg/kg/day) for 10 days. A filter soaked in 29% FeCl3was applied around the abdominal aorta to study the patterns of arterial thrombosis. The aortic blood flow was observed and continuously recorded using an ultrasonic Doppler flow probe. ADP-induced platelet aggregation, low-density lipoprotein oxidation induced by phorbol 12-myristate 13-acetate (PMA)-stimulated leukocytes, superoxide anion generation and superoxide dismutase (SOD) activity were also measured. RESULTS Both α- and γ-tocopherol decreased platelet aggregation and delayed time to occlusive thrombus (all p CONCLUSIONS This study indicates that both α- and γ-tocopherol decrease platelet aggregation and delay intraarterial thrombus formation, perhaps by an increase in endogenous antioxidant activity. γ-Tocopherol is significantly more potent than α-tocopherol in these effects.

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