SART STRESS EFFECTS ON LYMPHOCYTES IN THE THYMUS AND SPLEEN OF NORMAL, ADRENALECTOMIZED, AND SYMPATHECTOMIZED MICE

The effects of stress due to specific alteration of rhythm of temperature (SART) on lymphocyte subpopulations of the thymus and spleen were examined in C3H/He mice. Thymic and splenic involution were evident in SART-stressed mice, and lymphocyte subpopulations were significantly changed. In the thymus, CD4+ CD8+ and CD3- or CD3low lymphocytes were decreased by SART stress more than other lymphocytes, and CD4- and CD8-single-positive lymphocytes and B lymphocytes in the spleen were decreased equally. Immunoregulation via the adrenal glands and sympathetic nervous system was studied in chemically sympathectomized and adrenalectomized SART-stressed mice. Neither chemical sympathectomy nor adrenalectomy alone influenced the thymus or spleen in nonstressed mice, but chemical sympathectomy enhanced SART stress-induced thymic changes and further decreased the number of B lymphocytes in the spleen of SART-stressed mice; adrenalectomy blocked SART stress-induced thymic changes and increased the number of B lymphocytes in the spleen. These findings indicate that the genesis of thymic changes induced by SART stress is in the adrenal glands, and malfunction of sympathetic nerves and insufficient excretion of adrenal hormones could alter the balance of lymphocytes in the spleen during stress. It was also clear that thymic changes induced by SART stress could be immediately reversed to pretest conditions by alleviating the stress. © 1993 by Academic Press, Inc.