Physical Training Moderates Blood-Brain-Barrier Disruption and Improves Cognitive Dysfunction Related to Transient Brain Ischemia in Rats

摘要

Cerebral ischemia induces structural and functional damage in the brain, which leads to cell death and cognitive dysfunction. According to the evidences, physical exercise training exerts a neuroprotective effect and may decrease ischemia-induced injuries in this case. We evaluated the protective effects of physical training on blood-brain-barrier (BBB) disruption, neuronal death, and cognitive dysfunction induced by cerebral ischemia in male rats. Thirty-six adult male rats were selected randomly and allocated into three groups, ischemia (I), ischemia+exercise (I+E), and sham (Sh). Brain ischemia was induced via occlusion of the common carotid arteries for 20 min. Before occlusion, animals of the I+E group ran on a treadmill 5 days a week for 4 weeks. Spatial memory performances of rats were evaluated by the Morris water maze test. Apoptotic cell death in the dentate gyrus (DG) of the hippocampus was detected by a TUNEL assay, while the level of disruption of the BBB was measured by an Evans blue assay. Cerebral ischemia caused spatial memory impairment; exercise training improved the index of memory impairment following ischemia significantly (P < 0.05). Also, exercise training significantly reduced the BBB permeability in I+E rats compared with the I group (P < 0.05). In addition, the number of TUNELpositive cells was significantly greater in I rats, while exercise training significantly reduced apoptotic cell death (P < 0.05). Our results indicate that physical training exerts noticeable neuroprotective effects against brain ischemic injury, in particular by preserving the BBB integrity.