Cholinergic Signal Regulates Neural Stem Cell Differentiation In Perilesional Zone After Ischemic Stroke

Background and ObjectiveWith the increasing incidence and mortality rate of stroke,finding an effective threapy for it has attracted more and more attention.Our previous research revealed that the choline acetyltransferase positive neurons(ChAT~+neurons)within subventricular zone(SVZ)can promote neurogenesis after brain infarction,but the mechanisms are still unclear.This study investigated the effects of cholinergic signal on neural stem cell(NSC)differentiation in peri-infarction region after ischemic stroke.MethodsMice were randomly assigned into four groups(n=25 per group):sham+vehicle group,transient middle cerebral artery occlusion(tMCAO)+vehicle group,tMCAO+donepezil group and tMCAO+atropine group.The tMCAO model was made by the thread-occlusion method.Modified neurological severity score(mNSS)was used to evaluate neurological function recovery,and brain water content was assessed with dry–wet weight method on the third day after surgery.Immunofluorescence was used to label corresponding cells.All newborn neurons were tested by NeuN/5-bromodeoxyuridine(BrdU)staining,newborn oligodendrocytes were labelled by CNPase/BrdU staining,the newborn astrocytes were labelled by GFAP/BrdU staining.Statistical analysis was carried out with SPSS version 22.0.All results were expressed as mean±SD.We used repeated measures ANOVA to determine changes in neurologic deficit score among different groups.We used one-way ANOVA to analyze differences of data in the immunofluorescence analysis and brain water content analysis.P<0.05 was considered statistically significant.Results1.Donepezil-treated tMCAO mice had lower neurologic deficit scores than vehicle-treated tMCAO mice(P<0.05).2.Brain water content of mice in tMCAO+vehicle group was significantly higher than that of sham operation group on the third day after surgery(P<0.05).3.On day 14 and day 28 after tMCAO,the number of NeuN/BrdU,CNPase/BrdU and GFAP/BrdU immune-positive cells in MCAO+vehicle group were markedly increased as compared with those of sham+vehicle group(P<0.05).Compared with that of MCAO+vehicle group,the number of NeuN/BrdU-positive cells,CNPase/BrdU-positive cells and GFAP/BrdU-positive cells was higher in MCAO+donepezil group,and the number of NeuN/BrdU-positive cells and CNPase/BrdU-positive cells of MCAO+atropine group was lower(P<0.05).Conclusions1.Increased cholinergic signal can promote recovery of neurological function after ischemic stroke.2.Increased cholinergic signal can reduce cerebral edema after infarction.3.Increased cholinergic signal could promote NSCs differentiation in peri-infarction region after stroke.