The rat cerebral cortex maintains neuroplasticity, oxidative and inflammatory resilience following ultramarathon-like...

Ultramarathon races have been associated to modifications in brain function. We have previously reported that high-volume training (HV) under aerobic conditions induced oxidative stress in the rat cerebellum. An exhaustive test (ET), simulating an ultramarathon, modified GFAP-isoform expression profile suggesting impaired astrocyte reactivity. The present study investigated whether this type of oxidative and astroglial response occurs in the cerebral cortex (Cx). Adult male rats were divided into 4 groups according to HV and ET: control (CT), CT-ET, HV and HV-ET. Animals were trained on a treadmill running five times /week for 12 weeks with duration up to 90 min/day. Cx homogenates were analyzed for GFAP expression, reactive oxygen species (ROS), superoxide anions, nitric oxide (NO), GSH, GSSG, IL-1β , PSD-95, phosphorylated ERK1/2, JNK1/2 and CREB protein levels, superoxide dismutase (SOD) and catalase (CAT) activities. HV increased SOD and CAT activities and this effect was not modified by ET. HV increased GSH/GSSG ratio and reduced NO production, without effect on ROS, superoxide anions and IL-1β levels. The p-ERK1/2 /total-ERK1/2 ratio, p-JNK/total-JNK ratio, p-CREB and PSD-95 levels were not modified by HV while ET following HV increased p-JNK/total-JNK ratio. GFAP-protein levels of 39, 45, 50 and 55 kDa were increased by HV. Most of them were reverted to control values after ET. The Cx was resilient to HV-induced oxidative insult, increasing its redox balance and GFAP-protein expression, reduced NO levels and kept neuroplasticity neurochemical markers. Most training-induced responses were either reversed or maintained by ET, suggesting that ultramarathon-like race can induce a beneficial adaptive response in this brain region.