The poly(ADP-ribosyl)ation system in the testes of trained and exercising rats

Regular physical activity is associated with a general improvement of wellness (Schneider et al., Prev Cardiol 2000, 3: 77; Powers et al., Curr. Opin. Cardiol. 2002, 17: 495; Endres et al., Ann Neurol 2003; 54: 582). While the beneficial effects of exercise are well studied for the cardiovascular system and the metabolism, less is known as far as other organs and apparatus are concerned. Moreover, little attention has been payed to moderate or mild exercise (less or equal to 60 % VO2max), although such training pattern is representative of a widely used and advisable procedure for middle aged sedentary humans who initiate an exercise program. In particular, changes in hormone levels have been recorded to occur during exercise (Lehman et al., Br J Sports Med 1993, 27: 186), that, along with oxidative stress, may affect spermatogenesis (Hackney, Curr Pharm Des. 2001, 7: 261). However, differences between athletes and amatorial practitioners may be relevant (Manna et al., Acta Physiol Scand. 2003, 178: 33), and worth studying. We developed an animal model of moderate aerobic exercise training in young adult rats, that were trained to run on a treadmill 3 times a week, reaching 50-60 % VO2max, while controls leaded a sedentary lifestile. We have previously shown that such training pattern decreases ischemia-reperfusion cardiac damage and that oxidative stress may mediate these cardioprotective effects through a conditioning mechanism (Marini et al., submitted). Two subgroups of rats (trained and sedentary) were challenged with swimming in lukewarm water as a stressful stimulus, before killing and testis excision. We analysed rat testis poly(ADP-ribosyl)ation system as a biochemical marker of spermatogenesis in order to answer the following questions: How is spermatogenesis affected by moderate aerobic exercise training? Is apoptosis rate increased in the testis? Are there any signs of oxidative stress?