Proliferation and differentiation of endogenous neural stem cells and electroacupuncture interference in aged rats with cerebral ischemia and reperfusion

Objective To find out the protective mechanism of electroacupuncture in senile cerebral ischemia and reperfusion(I/R) lesion based on the proliferation and differentiation of endogenous neural stem cells in dentate gyrus(DG).Methods The rat model of cerebral ischemia was established by using the method of middle cerebral artery occlusion(MCAO).All rats were divided into the sham-operation group,model group,non-acupoint treatment group and acupoint treatment group.The immunohistochemistry assay was applied to detect the positive neuron count of bromodeoxyuridine(BrdU),neuronal nuclei,(NeuN) and glial fibrillary acid protein(GFAP) in DG.The changes of cerebral pathology,water content,integrals of neural symptoms,and cell proliferation and differentiation in DG were observed at different time points,i.e.cerebral ischemia for 3 hours,and reperfusion for 1,3,7 and 12 days respectively.Results In the model group the cerebral water content(at all time points),integrals of neural symptoms(at all time points),BrdU positive neurons(at all time points),BrdU/NeuN doubly labeled positive neurons(I/R for 3,7 and 12 d) and BrdU/ GFAP doubly labeled positive neurons(I/R for 7 and 12 d) were higher than those in the sham-operation group.There was no significant difference in all indexes between the model group and non-acupoint treatment group at all time points.In the acupoint treatment group the cerebral water content(I/R for 1,3 and 7 d),integrals of neural symptoms(I/R for 3,7 and 12 d) and BrdU/GFAP doubly labeled positive neurons(I/R for 7 and 12 d) were lower than those in the model group and non-acupoint treatment group,and BrdU positive neurons(at all time points) and BrdU/NeuN doubly labeled positive neurons(at all time points) were higher than those in the model group and non-acupoint treatment group.Conclusion The proliferation and differentiation of endogenous neural stem cells in DG can be stimulated by cerebral ischemia.The mechanism of electroacupuncture in acupoints against cerebral ischemia and reperfusion lesion may be related to that electroacupuncture can improve the proliferation and differentiation of endogenous neural stem cells in DG.