Effect of vitamin E supplementation on cellular immune functions decreased with aging in spontaneously hypertensive rats

Abstract

This study was performed to determine the effect of vitamin E supplementation on cellular immune functions decreased with aging in spontaneously hypertensive rats(SHR). Both Wistar Kyoto rats(WKY) as control rats and SHR, 6 weeks old, were fed a diet supplemented with 50 or 585 mg vitamin E/kg diet for 2 or 6 weeks. SHR fed the control diet were apparently in the vitamin E deficient status. In those SHR, mitogenesis and natural killer cell(NK) activity of splenocytes remarkably declined with aging while alveolar macrophage(AM) showed a higher phagocytic activity compared to that of WKY. Furthermore, high vitamin E diet could restore proliferations of thymocytes and splenocytes with phytohemagglutinin(PHA) and concanavalin A(Con A) in SHR. However, the effect of dietary vitamin E on T cell responses was strongly shown in WKY rather than SHR and in 2-week rather than those in 6-week. NK activity of splenocytes in SHR remained the decreased state even after 6 weeks-feeding of high vitamin E diet. These results suggest that vitamin E supplementation may restore, in part, cellular immune functions decreased with aging in SHR and the effect of high vitamin E diet may be limited in T cell responses.