Freewheel exercise training modifies pro- and anti-apoptotic protein expression in mouse splenic lymphocytes.

The purpose of this study was to examine the effect of voluntary training in mice on the expression of apoptotic proteins in splenic lymphocytes following acute exercise. Thirty-three mice were randomized to four treatments: 1) control group (no training and no acute exercise), 2) training, no acute exercise, 3) no training, acute exercise and 4) training, acute exercise. Mice were sacrificed immediately after acute exercise. Western immunoblotting was used to detect apoptosis in splenic lymphocytes for concentrations of anti- (Bcl-2) and pro-apoptotic (caspase 3) proteins. Plasma corticosterone was used as an index of exercise stress. Trained mice not given acute exercise challenge had elevated Bcl-2 (p < 0.05) and lower caspase 3 (p < 0.05) levels relative to control mice. Following the acute exercise challenge, however, trained and untrained mice did not differ in the concentrations of these proteins in splenocytes. Thus, freewheel exercise training in mice reduces splenic lymphocyte apoptosis when tissue samples are obtained at rest but not after acute exercise.