Influence of G-CSF on the brain edema and GFAP in rats with intracerebral hemorrhage

Objective To explore the influence of granulocyte colony-stimulating factor(G-CSF) on the brain edema and glial fibrillary acidic protein(GFAP) in intracerebral hemorrhage rats and to investigate its neuroprotective effect and mechanism.Methods Healthy and male SD rats were randomly divided into three groups: the sham operation group,the model group and the treatment group.The model of ICH was made by cutting off tail of rat to obtain blood.The treatment group was administered rhG-CSF(60 μg / kg) by intraperitoneal injection 1 h after operation.The brain edema was measured by dry-wet weigh method,MMP-9 and GFAP positive cells were measured by immunohistochemical method in every group after the operation 6 h,24 h,48 h,72 h,7 d and 10 d.Results The brain edema and contents of MMP-9 positive cells in the model group were markedly higher than the sham operation group(all P 0.05),reaching the peak at 48 h,72 h and the difference was significant compared with those at 6 h,24 h,7 d and 10 d(all P 0.05);the brain edema and contents of MMP-9 positive cells in the treatment group were significantly lower than the model group(all P 0.05).In the sham operation group,the changes of the contents of MMP-9 positive cells were not correlated with the brain edema(r =0.429,P 0.05).In the model and treatment groups,the changes of the contents of MMP-9 positive cells were positively correlated with the brain edema(r = 0.922,0.844,respectively;both P 0.05).There was not GFAP-positive cell in the sham operation group;in the model group,the GFAP was little expressed at 6 h,increased at 48 h,and there were large numbers of GFAP-positive cells at 72 h then reached a peak at 7 d;the expression of GFAP in the treatment group was identical to that of the model group at 6 h,however,the number of GFAP-positive cells was obvious decreased compared with that in the model group at 24 h,48 h,72 h and 7 d after intervention(all P 0.05).Conclusion G-CSF can down-regulate MMP-9 expression,decrease the brain edema and inhibit the activation of astrocytes,which may play an important role in the protection of the nerve tissues after intracerebral hemorrhage.