Study of the effects of endurance training programs on performance, cognitive, sensorimotor functions and brain plasticity in healthy and cerebral ischemic rats

Nicolas HUGUES

Team “Early activity in the developing brain”

Abstract: Beyond its important role in improving cardiovascular and muscular functions, chronic endurance exercise is now recognized to prevent neurological pathologies by promoting cerebral plasticity. Indeed, endurance training can alter both the cortex and the hippocampus, two of the brain areas highly sensitive to endurance training, playing a major role in motor and cognitive functions. However, although increasingly studied, endurance training benefits on brain health and behavior remain controversial due to the diversity of the protocols used. Indeed, these training protocols are rarely individualized, last from few days to many weeks and lack intermediate time-points of measurement to better understand the kinetic of their effects. Among these endurance training regimens, two of them appear to be of interest. Obviously, the first is the traditional Moderate-intensity continuous training (MICT), while the second is still gaining popularity, the High-intensity interval training (HIIT). Hence, the first study of this manuscript aimed to define the time-dependent effects of work-matched HIIT and MICT on cortical plasticity, endurance, and sensorimotor performances over an 8-week training period in healthy rats. The results indicate an early and superior endurance improvement with HIIT than MICT. Nevertheless, MICT promoted an early increase in markers of neuroplasticity. However, while MICT beneficial effects appeared to decrease over the time, HIIT seemed to upregulate neurotrophic, metabolic and angiogenic markers at 2 and 8 weeks. Hence, HIIT and MICT appeared to be effective in a time-dependent manner suggesting a complementary effect that might be useful in physical exercise guidelines for maintaining brain health.
Interestingly, in addition to their role in optimization and prevention of brain heath and cardio-vascular diseases, endurance training regimens remain under study for their therapeutic effects following cerebral ischemia. Although HIIT with long intervals have already shown a slight superiority to work-matched MICT during the critical period of plasticity (i.e. the first weeks in rodents), they remain insufficient to promote a complete functional recovery. Hence, the second and third studies aimed to define the effectiveness of HIIT with long vs. short interval on both ipsi- and contralesional cortices as well as on functional and cognitive recovery during the first two weeks following cerebral ischemia. While both regimens were effective in enhancing endurance performance and cortical plasticity in the contralesional cortex mainly, long-HIIT appeared to promote an early grip strength complete recovery. However, in both healthy and stroke rats, endurance training regimens remain insufficient in promoting cognitive enhancement and limiting cognitive decline. As endurance training on treadmill do not request high cognitive demand, its combination to a cognitive training could potentially end up in limiting cognitive decline early after stroke. Thus, the effectiveness of combining a cognitive training to MICT and HIIT is the purpose of the fourth study of this manuscript, which is still on going.

Jury
Christophe PORCHER, Président du jury – INMED UMR 1249, Marseille
Anne TESSIER, Rapporteure – CAPS U1093, Dijon
Mathieu GRUET, Rapporteur – UMR DMEM, Montpellier
Olivier DUPUY, Examinateur – MOVE UR2096, Poitiers
Éric BERTON, Co-directeur de thèse – ISM UMR 7287, Marseille
Jérôme LAURIN, Co-directeur de thèse – INMED UMR 1249, Marseille

Thursday 9 March 2023 at 2pm, Inmed conference room