Apply Of IGF-1 And NSCs On Alzheimer Disease Model Rat

Alzheimer' s disease is one of the major neurodegenerative disease that cause progressive cognitive and behavior deterioration. Affected brain of AD patients are characterized by the presence of senile plagues and neurofibrillary tangles. Another pathological festure is the region-specific degeneration of neuronal population, particularly in the areas connected to the hippocampus and pallium. Neural Stem Cells is a kind of stem cells defined as neural cells with the potential to self-renew and to generate all the different cell types of the nervous system following differentiation: astrocytes, oligodendrocytes, neurons. Neural stem cells exist in the subventricular zone (SVZ) of lateral ventricle and the dentate gyrus (DG) of hippocampus in central neural system (CNS) throughout the life of adult mammals. The proliferation and differentiation of neural stem cells is tightly related to the environment they live and regulated by many factors Insulin-like growth factor-1 (IGF-1) is a multifunctional polypetide hormone that has demonstrated effects on these neural progenitor cells. The IGF-1 and receptor are distributing proverbially in CNS of mammals. It can stimulate the survival, proliferation, differentiation, and maturation of NSCs. As the potential to self-renew and to differentiate into all three kind of neural cells in some conditions, the replacement strategies to treat with the diseaseof CNS is reasonable. We isolate and culture rat' s embryonic neural stem cells in vitro, then transplant these cells which were labeled by BrdU into the hippocampus of AD or\and infuse insulin-like growth factor-1 into hippocampus of AD model rats. We studied the survival, prolifferation, differentiation of exogenous and endogenous neural stem cells and the effect of antiapoptosis. We observed the changes of learning and memory ability of rats.Materials and Method: AD model was established by infuse Amyloid 13 protein into the rats' hippocampus In this study ,24 healthy Wistar rats(280-320g) were randomly divided into four groups. Namely, A ï¿¡ group, IGF-1 group, NSCs group and IGF-1+NSCs group. We isolate and culture rat' s embryonic neural stem cells in vitro, then transplant these cells which were labeled by BrdU into the hippocampus of AD or\and infuse insulin-like growth factor-1 into hippocampus of AD model rats. The rats are killed two weeks after transplantation and the brain sections concluding hippocampus were cut to perform TUNEL and immunobiomedichal examination. The expression of mouse telomerase RNA was also determined,, The learning and memory ability was measured by Y maze. Results:1. Identification of NSCs and evaluation of their proliferating capability when cultured in vitro for 10 days, almost all the cells were nestin-positive cells; about half a cultured cells were BrdU-positive cells.2. BrdU-positive cells were found in the hippocampus. Some of them migrated into lateral cerebral ventricle, subventricle zone and beside the blood vessels. Cells of double labeled with anti-BrdU and GFAP were more often seen in the cortex whereas more cells with anti-BrdU and NF in the hippocampus, and both of them in the ventricle. The numbers of doubled labeling cells against BrdU and GFAP, and againstBrdU and NF were higher remarkably in IGF group, NSC group and NSC+IGF group than which in AB group(P<0. 01) ? Doubled labeling cells against BrdU and GFAP, and against BrdU and NF were more often seen in NSC+IGF group than IGF group and NSC group(P<0. 05)? .3. The m-TR expression levels are different in all these groups . In A group and IGF group have not m-TR expression. In NSCs group and NSCs+IGF group have m-TR expression .4. Compared with AD model group, the numbers of positive expression of apoptotic neurons was remarkably increased in cerebral remarkably in the brain of other groups(P<0.01) ?5. Behavioral testThe learning and memory ability of AD models is decreased remarkably. And it enhanced obviously after grafting of NSCs and injecting of IGF-1. There is statistically tremendous difference between AD model group and the other groups. Conclusion:IThe neural stem cells that were translated into AD model rats can be alive and proliferate and differentiate into the mean three kinds of cells in brain.IGF-lcan mobilize the endogenous stem cells to proliferate and differentiate. When NSCs and IGF-1 are both used the effects can be highten.2. IGF-1 and the technique of neural stem cells transplantation can inhibit neural cells to apoptosis.3 The result of behavioral test indicate that transplanting NSC can ameliorate the symptum of Anamnesis decline and is promising to cure the neurodegenerative disease of CNS.