Protective mechanism of the different doses of insulin-like growth factor-2 for focal cerebral ischemia reperfusion injury

【Objective】IGF-2 plays an important role in protecting cerebral ischemic reperfusion injury,S100B protein is a marker of nerve cell Injury,secreted by gliocyte,Now no report is about the dynamic observation of S100B protein after the different doses of IGF-2 supplyed after cerebral ischamic reperfusion injury home and abroad.The research is to study the possible mechanism of the effects of the different doses of IGF-2 towards focal cerebral ischamic reperfusion Injury by the dynamic observation of s100B protein at the different time after the cerebral ischamic reperfusion Injury.【Methods】66 SD rats were operated to establish focal cerebral ischamic reperfusion Injury model and were divided into 3 groups randomly: imitational operation control group(6 rats),cerebral ischemic reperfusion Injury group(15 rats),treatment of IGF-2 group(low dose group 15 rats、moderate dose group 15 rats、high dose group 15 rats).All these 3 groups were divided into 3 subgroups(12h、1day、3day).One hour after cerebral ischemia,Cerebral ischamic reperfusion is finished.Immunohistochemistry were used to observe apoptosis of neuronal cells at the central and around the focal cerebral ischemia and detect the expression of S100B protein. 【Results】The result showed that compared with imitational operation control group,the expression of S100B protein in ischemic reperfusion injury group increased greatly(p0.05);compared with ischemic reperfusion injury group,the expression of S100B protein in the moderate and high dose of treatment group decreased greatly(p0.05),but no statistical significance was found in low dose group;By the Tunel detection we can see that the number of neuronal cells' apoptosis in the moderate and high dose of IGF-2 treatment group decreased clearly compared with ischemic reperfusion injury group(p0.05);Compared with imitational operation control group,the expression of S100B protein in ischemic reperfusion injury group increased greatly(p0.05);the defference between the moderate and high dose of treatment group has obvious statistical significance in the expression of S100B protein and the number of neuronal cells' apoptosis(P﹤0.01).【Conclusion】IGF-2 can not only reduce the number of neuronal cells' apoptosis and the expression of S100B protein greatly,which should be presumed one of its brain protective mechanisms;We Speculated that dose-effect relationship exists in IGF-2 treatment of focal cerebral ischemia-reperfusion brain injury,the therapy efficacy may be improved with the dose increased.