Exercise pre-conditioning alleviates brain damage via excitatory amino acid transporter 2 and extracellular signal-regulated kinase 1/2 following ischemic stroke in rats

Previous studies have reported that physical exercise may exert a neuroprotective effect in humans as well as animals. However, the detailed mechanisms underlying the neuroprotective effect of exercise has remained to be elucidated. The aim of the present study was to explore the possible signaling pathways involved in the protective effect of pre-ischemic treadmill training for ischemic stroke in rats. A total of 36 male Sprague-Dawley rats were divided at random into three groups as follows (n=12 for each): Sham surgery group; middle cerebral artery occlusion (MCAO) group; and exercise with MCAO group. Following treadmill training for three weeks, the middle cerebral artery was occluded for 90 min in order to induce ischemic stroke, followed by reperfusion. Following 24 h post-reperfusion, six rats from each group were assessed for neurological deficits and then sacrificed to calculate the infarct volume. The remaining rats (n=6 for each group) were sacrificed and the expression levels of excitatory amino acid transporter 2 (EAAT-2) and extracellular signal-regulated kinase 1/2 (ERK1/2) were detected using western blot analysis. The results of the present study demonstrated that rats that underwent pre-ischemic exercise intervention had a significantly decreased brain infarct volume and neurological deficits; in addition, the pre-ischemic exercise group showed decreased overexpression of phosphorylated ERK1/2 and increased expression of EAAT-2 following ischemic stroke. In conclusion, treadmill training exercise prior to ischemic stroke alleviated brain damage in rats via regulation of EAAT-2 and ERK1/2,