Decreased mitogen response of splenocytes in senescence accelerated mice (SAM-P1) is not restored by high vitamin E diet

We have previously found that vitamin E (VE)has an ability to restore the d ecreased mitogen response of splenocytes in spontaneously hypertensive rats (SHR) as a model of aging. The aim of this study is to investigate whether high VE diet can restore the decreased mitogen response of splenocytes in SAM-PI as mouse model of aging. Male SAM-PI and -R1 as control, 9 months ol d, were fed control (50 mg VE/kg diet) or high VE diet (585 mg VE/kg diet). Male SAM-RI, 4 weeks old, were used as young control. After 4 weeks, they were killed under anesthesia and their cellular immune functions were assay ed. There was no significant differense in serum VE concentration between o ld SAM-RI and -P1. In addition, high VE diet induced the similar increase o f serum VE concentration in both old SAM-RI and -P1. Mitogen response of sp lenic lymphocytes with concanavalin A (Con A) was remarkably decreased in S AM-PI compared with those of young and old SAM-RI. High VE diet did not hav e the ability to restore the decreased mitogen response of splenic lymphocy tes in SAM-PI. The percentage of adherent cells, mainly macrophages (M phi) , in splenocytes was also remarkably decreased in old SAM-PI. Furthermore, M phi isolated from splenocytes of SAM-PI did not have the enhancing effect on proliferation of splenic lymphocytes from young SAM-RI. These results s uggest that the decreased mitogen response of splenic lymphocytes in SAM-Pi is not restored by high VE diet and may be associated to the decreases of both number and function of M phi. (C) 1999 Elsevier Science Inc.