The Effect Of Recombinant Huaman Granulocyte Colony-stimulating Factor On The Expressions Of AQP4 And GFAP Following Cerebral Ischemia/reperfusion Injury In Rats

Objective:To explore the protection mechanism of Recombinant human granulocyte colony stimulating factor(rh G-CSF) on blood brain barrier(BBB)by observing the change of expression of AQP4、GFAP in SD rats with cerebral ischemia-reperfusion injury.Methods:Thirty-nine male SD rats were randomly divided into the Sham-operated group、the model group and the rh G-CSF treatment group, thirteen rats were included in each group.The middle cerebral artery occlusion was established by the modified Longa suture method. In the treatment group, a single dose of 50 μg/kg rh G –CSF was injected subcutaneously after cerebral ischemia 2 hours.The other groups were given the same volume of saline.Using Longa 5-point scale estimate the neurological function;The expression level of AQP4 and GFAP were detected by immunohisto-chemistry; The ultra structure changes of blood brain barrier after cerebral ischemic reperfusion were observed by transmission electron microscopic technology.Results:1. There were not any neurological deficits in the Sham-operated group, The model group and the treatment group showed different degree of paralysis:decreased activity, and less food intake, and the neurological function in the treatment group was improved,the difference between the treatment group(1.31±0.63) and model group(2.46 ± 0.66) hadstatistically significant(P < 0.01).2. Compared with the Sham-operated group(7.38 ± 2.72),the Evans blue content of the control model group(37.11 ± 3.06) increased significantly(Pt<0.01);compared with the Evans blue content in the treatment group( 22.75±4.61),the control model group decreased significantly(P<0.01);3. The AQP4,GFAP expression of grey value in the treatment group were 180.67 ±7.72,160.64 ± 5.07 respectively,higher than the control model group(t = 24.16, P < 0.01)(t = 17.98, P < 0.01)]; The AQP4、GFAP expression of grey value in the Sham operated were 202.08 ± 5.80,173.73± 4.40 respectively,higher than the control model group(t =46.07,P < 0.01;t = 31.07, P < 0.01).4.Observed under electron microscope, Tight Junction of the sham operated group was clear,the endothelial cells nuclear morphometry was good,the basilemma thickness was uniformity. The Model group connection between the brain capillary endothelial cells was flabby, the gap became wider, and the basement membrane electron density was reduced, the surrounding normal brain tissue was damaged; Compared with the model group,the treatment group connection between the brain capillary endothelial cells was close, basement membrane electron density was slightly higher.Conclusions:1. rh G-CSF can improve nerve function defect of ischemia reperfusion injury.2. rh G-CSF can improve the permeability of blood brain barrier after ischemia reperfusion injury, reduce the occurrence of edema injury in early cerebral injury.3. rh G-CSF has a protective effect to cerebral ischemia reperfusion injury, the possible mechanism is that it can reduce the expression of GFAP、AQP4 by inhibiting excessive activation, relief brain edema, then protect the integrity of the BBB.