Recombinant Human Granulocyte Colony-Stimulating Factor Attenuates Delayed TPA-induced Hemorrhagic Transformation In Ischemic Stroke Rats By Reducing MMP-9 Expression

PART 1Objective:To establish suitable experimental model for subsequent study by selecting appropriate line bolt diameter.Methods:Male Sprague–Dawley rats(n=20,weight 250±20)were used which randomly divided into 2 groups,group A and B.The model of MCAO were esblished with the Longa method.The bolt diameter used in group A was 0.26 mm while 0.30 mm in group B.The reperfusion was at 6 hours after MCAO.24 hours post treatment,using Longa 5-point scale estimated the neurological function and TTC method measured cerebral infarction volume.Results:The neural function defect scale 2.4±0.69 in group A, 3.1±0.73 in group B,there is statistical significance difference(P<0.05).2.All survived after ischemia-reperfusion in group A,but in group B there were 3 rats characterized by loss of consciousness and 1only dead indicating that the success(1-3 points) rate of group A are higher than group B.3.Through TTC stain,the brain slices was red in normal brain tissue section while white color in infarction area.The result shows:the cerebral infarction in group A was smaller than B.Conclusion:The success rate was higher in the model made by a diameter of 0.26 mm line,which can cause stable MCAO for subsequent experiments.PART 2Objective:To explore the effect of rhG-CSF with expression of matrix metalloproteinases-9(MMP-9) and incidence rate of hemorrhagic transformation after ischemia rats beyond the therapeutic time window(6hours) after thrombolysis treatment,and provide theoretical basis for expanding thrombolysis time window.Methods:Selected 36 healthy male SD rats,according to the first part of the preparation of MCAO model, were randomly divided into 3 groups, blank control group, rt-PA group and combined treatment group(n=12).All rats were given reperfusion after 6h of ischemia,at the same time,rt-PA group was administered with rt-PA 10 mg/kg, combined treatment group given rt-PA(10 mg/kg)+rh G-CSF(300μg/kg),blank control group only for volume of physiological saline.24 hours post treatment,using Longa 5-point scale estimated the neurological functiontion defect scale,immunohistochemical method to measure the expression of MMP-9 and spectral photometric method measuring cerebral hemorrhage.Results:1. All rats after MCAO showed the neural function defect, Longa score value of the treatment group is lower than the other two groups.2.The expression of MMP-9 in lesions was higher than the contralateral side.MMP-9’s expression increased significantly in rt-PA group compared with the blank control group while declined in combination group.3.The amount of bleeding comparison results showed that the rt-PA group increased significantly compared with blank control group and in the combined treatment group was obviously reduced.Conclusion:Rh G-CSF attenuates delayed t PA-induced hemorrhagic transformation in ischemic stroke rats by reducing MMP-9 expression.