ABSTRACT
Background To investigate the expression of the early growth response gene-1 ( Egr-1 ) mRNA after focal cerebral ischemia / reperfusion in rats.Methods Ten healthy male SD rats weighing 200 ～ 250 g were used to create model of focal cerebral ischemia. The expression of Egr-1 after focal cerebral ischemia/reperfusion in rats was determined using in situ hybridization and RT-PCR.Results (1) The result of the in situ hybridization: A trace amount of Egr-1 mRNA expressed in the neurons and the glial cells in the sham operated group. The expression of Egr-1 mRNA at the ischemic side increased dramatically following ischemia and reached peaks after 4 hours' reperfusion. Egr-1 expression started to subside following 22 hours' reperfusion and further decreased following 166 hours' reperfusion, which was still significantly higher than that in the sham operated group. (2) The result of RT-PCR: The expression of Egr-1 mRNA at the ischemic side was significantly higher than that in the sham operated group at all time points after ischemia/reperfusion in the rats(P ＜0. 01). Expression of Egr-1 increased 2 h after ischemia and reached the peak 4 h following reperfusion, and then decreased dramatically at 46 h after reperfusion which was still higher than that in the sham operated group (P ＜ 0. 01). As the ischemia/reperfusion period prolonged, the expression of Egr-1 mRNA increased gradually, but still detectable even 166 h following reperfusion. The expression of Egr-1 was significantly higher than that in the sham operated group at all time points (P ＜0. 01).Conclusions The expression of Egr-1 mRNA increase in the neurons and the glial cells after ischemia/reperfusion, which may have protective effects on ischemic brain tissues.