ABSTRACT
Objective To investigate the expressions of erythropoietin(EPO)and its receptor(EPO-R)in the spinal cord after acute traumatic injury in adult rats.Methods Sixty-nine Wistar rats were randomly divided into three groups:normal control group(n=5),spinal cord injury group(n=32),and sham operation group(n= 32).The injury group and sham operation group were further randomly divided into eight subgroups respectively (n=4)(1h,6h,12h,24h,3d,7d,14d,28 dafter operation).The expressions of EPO and EPO-R at different time points were detected by RT-PCR,Western blot and immunohistochemical staining.Results EPO was nut detected at any time point in the normal control grnup,spinal cord injury group or sham operation group.The EPO-R expression was not found in the normal control group or sham operation group.RT-PCR and Western blot analyses revealed EPO-R mRNA and protein expressions in the injury group as early as 6 h after injury.The EPO-R mRNA and protein expressions sharply increased at 12 h,peaked at 24 h to 7 d,and gradually declined after 7 d. They were still higher than those in the control rats 28 d after injury.The EPO-R immunoreactivity was chiefly found in neurons,oligodendrocytes,vascular endothelial and ependymal cells.Conclusion The EPO-R expression can be up-regulated obviously in the injured spinal cord,which provides a molecular basis for the nerooprotection of exogenous EPO.