PP.38.03] THE IMPACT OF EARLY OR LATE EXERCISE TRAINING ON THE MICROVASCULAR ALTERATIONS INDUCED BY CEREBRAL HYPOPERFUSION

Abstract

Objective: To investigate the impact of early or late exercise training (ET) on brain microcirculatory and inflammatory parameters after an experimental model of cerebral hypoperfusion induced by bilateral common carotid artery occlusion (2VO) in rats. Design and method: Wistar rats aged 12 weeks were randomly divided into two groups: Sham and 2VO and then divided into two intervention groups: (1) Early intervention with physical exercise group, starting the ET three days after 2VO and (2) Late intervention with physical exercise group, starting the ET ten days after the 2VO. Finally, each intervention group was divided into three subgroups of 10 animals: (1) Sham sedentary group (Sham Sed); (2) 2VO sedentary group (2VO Sed) and (3) 2VO+exercise group (2VO+Ex). The animals of the exercised group were subjected to the maximum incremental test (MIT) for the adequate prescription of exercise intensity each training session consisted of seven days, for 30 minutes at 60 % of maximum speed (MIT). Cerebral blood flow (CBF) was evaluated by laser speckle contrast imaging; brain functional capillary density and endothelial-leukocyte interactions were evaluated by intravital video-microscopy and the gene expression of the NADPH oxidase by real time PCR. Results: The 2VO model was induced a decrease of brain functional capillary density in 2VO-Sed group compared to Sham Sed (225 ± 28 vs. 337 ± 28 capillaries/mm2, respectively; p < 0.05), a decrease of 19% in cerebral blood flow, increased leukocyte-endothelial interactions, and although not significant, induced increases of gene expression of NADPH oxidase and IL-6. Both exercise protocols promoted increases in CBF (about 6%) and functional capillary density (2VO+Ex early 290 ± 29 and 2VO+Ex Late 279 ± 37 capillaries/mm2, p < 0.05). Only the early intervention group showed a significant effect of exercise on endothelial-leukocyte interactions (2VO-Sed 5.0 ± 0.6 vs. 2VO+Ex early 1.0 ± 0.3 cells/min, p < 0.05). Although not presenting statistical differences, early intervention reduced the gene expression of NADPH-oxidase (2VO+Ex early: 1.7 ± 0.2 vs. 2VO Sed: 3.3 ± 0.9 APU). Conclusions: Cerebral microcirculatory and inflammatory changes appear to be triggered in first days after 2VO. Therefore, and early exercise intervention can be considered a preventive approach for neurodegenerative diseases caused by chronic cerebral hypoperfusion.