Objective:To explore whether intranasal administration of recombinant human granulocyte colony stimulating factor can relieve free radicals injury following experimental subarachnoid hemorrhage.Methods:Rat SAH models was induced by double injection of autologous blood into the cisterna magna.The rats were randomizedly divided into normal control group

SAH group

SAH+NS group

and SAH+rhGCSF group.Coronal sections were made to observe the neuropathology of the cortex and the CA1 region of the hippocampus.Superoxide dismutase(SOD)activity and content of malondialkhyde(MDA)in the brain tissue homogenate were detected 24 hours after secondary cisternal injection.Results:①Compared with normal control group

the number of neuronal cells in cortex and hippocampal CA1 region were significantly reduced

the structural arrangement was disordered and morphology was abnormal in SAH group and SAH + NS group

rhGCSF treatment could relieve this injury.②SOD activity was significantly decreased and the content of MDA was significantly increased on 24 hours after SAH induction.There is no statistically significant difference between SAH group and SAH+NS group.The content of MDA was decreased(P<0.05)and SOD activity was increased(P<0.01)in SAH+rhGCSF group compared with SAH group and SAH+NS group.Conclusion:Intranasal administration of recombinant human granulocyte colony stimulating factor can relieve bain injury mediated by oxygenic free radicals and attenuate early brain injury following experimental subarachnoid hemorrhage.