Unlike Physical Exercise, Modified Environment Increases the Lifespan of SOD1G93A Mice However Both Conditions Induce Cellular Changes

Background: Amyotrophic lateral sclerosis (ALS) is characterized by a gradual muscular paralysis resulting from progressive motoneurons death. ALS etiology remains unknown although it has been demonstrated to be a multifactorial disease involving several cellular partners. There is currently no effective treatment. Even if the effect of exercise is under investigation for many years, whether physical exercise is beneficial or harmful is still under debate. Methods and Findings: We investigated the effect of three different intensities of running exercises on the survival of SOD1G93A mice. At the early-symptomatic stage (P60), males were isolated and randomly assigned to 5 conditions: 2 sedentary groups (‘‘sedentary’ ’ and ‘‘sedentary treadmill’ ’ placed on the inert treadmill), and 3 different training intensity groups (5 cm/s, 10 cm/s and 21 cm/s; 15 min/day, 5days/week). We first demonstrated that an appropriate ‘‘control’ ’ of the environment is of the utmost importance since comparison of the two sedentary groups evidenced an 11.6 % increase in survival in the ‘‘sedentary treadmill’ ’ group. Moreover, we showed by immunohistochemistry that this increased lifespan is accompanied with motoneurons survival and increased glial reactivity in the spinal cord. In a second step, we showed that when compared with the proper control, all three running-based training did not modify lifespan of the animals, but result in motoneurons preservation and changes in glial cells activation. Conclusions/Significance: We demonstrate that increase in survival induced by a slight daily modification of th