The Experiment Study Of Protective Effect Of Recombinant Human Granulocyte Colony Stimulating Factor On Cerebral Ischemia

IntroductionCerebral ischemia infarction is a serious disease with high incidence in middle-aged and old people.Although there are many kinds of measures in treating this disease,few of them are satisfied.Many projects have been conducted to find the method to reduce the incidence and ameliorate the prognosis after ischemia.It was reported that recombinant human granulocyte colony stimulating factor(rhG-CSF)protect the brain from the injury after cerebral ischemia,but the mechanisms are not clearly understood.We hypothesized that rhG-CSF may remove the hematopoietic stem cell to brain and reduce the neuron death following cerebral ischemia.In this study,two kind of cerebral ischemia animal models were used to investigate the mechanism of the protective effect of rhG-CSF on brain from ischemia injury.Materials and MethodsThe male gerbils were randomly divided into three groups,including control group one,experimental group one and sham-operation group one. The experimental group one was treated with rhG-CSF(60μg/kg,i.p.,1ml) 30 min after cerebral ischemia-reperfusion.The control group one and sham-operation group one were treated with normal saline(i.p.,1ml).The gerbils were sacrificed at different time points(1d,2d,or 7d)after the rhG-CSF or NS treatment.On hippocampal tissue slices,nissl staining was used to observe the delayed death of neurons,immunofluorescent histochemical staining was used to calculate the concentration and distribution of CD34⁺ cells.Focal cerebral ischemia was induced by photochemically initiated thrombosis.The male adult SD rats were randomly divided into four groups, including control group two,experimental group two,experimental group three and sham-operation group two.Seven days before cerebral ischemia, animals in experimental group two(low dose)and experimental group three (high dose)were treated with 60μg/kg(i.p.,1ml)and 120μg/kg(i.p.,1ml) respectively every day.Animals in control group two and sham-operation group two were treatment with NS.The animals were sacrified at different time points(4h,24h)after cerebral ischemia(or sham operation).The activity of SOD,the content of MDA and the area of infarction in their brain were measured.Results1.In the animals of experimental group one,the number of pyramidal cells in CA₁ is 123±8.5/mm²(n=10),significantly higher than that of control group one(46±5.2/mm²,n=10,P＜0.01)but lower than that of sham-operation group one(236±12.1/mm²,n=10,P＜0.01).2.In dentate gyrus of animals of experiment group one,a few CD34⁺ cells were observed one to two days after reperfusion,and a few blood vessels like CD34⁺ cells were found seven days after reperfusion.One to seven days after reperfusion,there was no CD34⁺ cells in dentate gyrus of animals of control group one or sham-operation group one. 3.In the brain of experimental group three,the activity of SOD increased and the content of MDA decreased compared with that of the control group two(P＜0.05).4.The infarction area in the brain of the animals of control group two is greater than that of experimental group two and experimental group three (P＜0.05).Conclusion1.Recombinant human granulocyte colony stimulating factor protects the brain from cerebral ischemia-reperfusion injury and this effect may be attributed to removing hematopoietic stem cell to brain.2.Recombinant human granulocyte colony stimulating factor increase the activity of SOD and decreases the content of MDA by protecting the brain from injury following cerebral ischemia.