Effects of erythropoietin preconditioning on rat cerebral ischemia-reperfusion injury and the GLT-1/GLAST pathway

The aim of the present study was to investigate whether erythropoietin (EPO) preconditioning affects the expression of glutamate transporter 1 (GLT-1) and glutamate aspartate transporter (GLAST) and protects against rat cerebral ischemia-reperfusion injury. A total of 140 Sprague Dawley rats were randomly assigned to one of the following four groups: Sham, EPO-sham, middle cerebral artery occlusion (MCAO) and EPO-MCAO. Neurological function scores were obtained 24, 36 and 72 h after reperfusion. Seventy-two hours after the induction of cerebral ischemia-reperfusion, the number of apoptotic neural cells and the cerebral infarct volume of each group were measured. The mRNA levels of GLT-1 and GLAST were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, while the GLT-1 and GLAST protein levels were assessed using western blotting. The cerebral infarct volume was significantly increased in the MCAO group compared with that in the sham group (P<0.01); however, the infarct volume of the EPO-MCAO group was significantly lower than that of the MCAO group (P<0.01). In addition, the number of apoptotic cells found in the MCAO group was higher than that in the sham group (P<0.01), but the number of apoptotic cells in the EPO-MCAO group was significantly lower than that in the MCAO group (P<0.01). The GLT-1 and GLAST mRNA and protein levels were significantly decreased 72 h after the cerebral ischemia-reperfusion (P<0.01) compared with those in the sham group, whereas the same levels were increased significantly in the EPO-MCAO group relative to those in the MCAO group (P<0.01). In conclusion, EPO preconditioning protected against cerebral ischemia-reperfusion injury and upregulated the GLT-1 and GLAST expression.