Long-term feeding of high vitamin E diet improves the decreased mitogen response of rat splenic lymphocytes with aging.
This study was performed to investigate whether the long-term feeding of a high vitamin E (VE) diet has a beneficial effect on the decreased cellular immune functions caused by aging. Male Fisher rats, 12 weeks old, were fed a regular (50 mg VE/kg diet) or high VE diet (585 mg VE/kg diet) for 12 months. Then, the rats were sacrificed under anesthesia and their cellular immune functions were measured. The proliferation of splenic lymphocytes with PHA or Con A was significantly lower in old rats fed the regular diet as compared to that of young rats (two months old). In contrast, the proliferation of splenic lymphocytes in old rats fed the high VE diet was similar to that of young rats. The in vitro effect of macrophages (M phi) on the proliferation of splenic lymphocytes from young rats was investigated under Con A stimulation. Although splenic M phi isolated from old rats fed the regular diet did not have any effect on the proliferation of splenic lymphocytes, M phi from old rats fed the high VE diet significantly enhanced the proliferation of splenic lymphocytes. The responsiveness of splenic lymphocytes isolated from each group to the M phi of young rats under Con A stimulation was not significantly different between the young rats and old rats fed the regular diet. In old rats fed the high VE diet, the responsiveness of splenic lymphocytes to young rat M phi was significantly higher than that of the young rats or old rats fed the regular diet. Furthermore, the high VE diet induced a significant increase in interleukin 2 (IL2) production from splenocytes in both young rats and old rats following in vitro stimulation with Con A for 48 h. These results suggest that VE has the ability to improve the decreased cellular immune functions caused by aging, and appears to be associated with the enhancement of both M phi functions and lymphocyte responsiveness.
Sakai
S
S
Department of Nutrition, School of Medicine, University of Tokushima, Japan.
Moriguchi
S
S
D000375:Aging / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004032:Diet; D004435:Eating / Q000187:drug effects; D007111:Immunity, Cellular / Q000187:drug effects; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects*; D008264:Macrophages / Q000276:immunology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D014810:Vitamin E / Q000008:administration & dosage*
D007376:Interleukin-2; D014810:Vitamin E