Physical exercise activates the poly(ADP-ribosyl)ation system in rat testes

Given the high sensitivity of the male reproductive system to oxidative stress and to temperature changes, the amount of germ cell apoptosis and the activation of the poly(ADP-ribosyl)ation system (a very sensitive index of genotoxic stress) were evaluated in the testicular tissue of adult rats which underwent a 10-wk treadmill training, according to either a mild or a strong protocol; rats were sacrificed 24 h after the last training session or after a single bout of an additional stressing exercise (30 min of swimming). Controls were untrained rats (one resting group and one group with acute exercise). Both training and acute exercise increased marginally germ cell apoptotic indexes (caspase-induced poly(ADP-ribose) polymerase fragmentation and TUNEL-positive cells), while the activity of poly(ADP-ribose) polymerase and poly(ADP-ribose) glycohydrolase enzymes was affected in a way that suggests that acute exercise is associated with reversible genotoxic stress, and that training induces adaptive responses, as demonstrated by the activation of poly(ADP-ribose) polymerase system without subsequent increase in apoptosis.