| Alzheimer's disease (AD) is an increasingly common neurodegenerative disorder of middle and old age which is characterized by cognitive deficits. Selective neuronal loss, neurofibrillary tangles and senile plaque are main neuropathological hallmarks of AD.There are various kinds of learning and memory disorder models. But the accepted and applicable AD model is still lack. So it is important to establish a reliable AD model.There is no effective treatment now. In early 90's, neural stem cells (NSCs) were isolated from central nervous system of embryonic and adult mammals, then it was regarded as the ideal cells to treat the neurodegenerative disorder by transplantation.In our study, incubated 3 -amyloid protein (1-40) (A?-40) was microinjected into the hippocampal CA1 subfield to establish AD model. Neural stem cells were isolated from dentate gyrus of hippocampus of newborn rats, and they were grafted into hippocampus of AD rats. Hoechst33258-lable technique and PCNA immunohistochemistry were applied to detect the survival and proliferation ofimplanted NSCs. Synaptophysin immunohistochemistry was used to study the possible mechanism.Y-maze was used to choose the rats which are sensitive to electric shock and escape rapidly after shocked. Rats were divided into control, sham-operation, AD, 2-week-transplantation and 4-week-transplantation groups randomly (n=6 per group). A. 1-40 was microinjected into the bilateral hippocampal CA1 subfield to establish AD model. Equal volume of saline solution was injected into the sham-operation group. No treatment was applied to the rats of control group. Y-maze was used to evaluate rats learning and memory ability in control, sham-operation and AD group respectly. To identify the neuropathological hallmarks of AD,the special staining were used as follows: haematoxylin-eosin (HE), Congo Red, Gros-Bielschowsky silver staining and Nissl staining. 5 1 Hoechst33258-labelling cells were injected to the the bilateral hippocampal CA1 subfield with same method on the same location of AD model. Behavioral test, fluorescence observation, PCNA and synaptophysin immunohistochemistry were used at 2 or 4 weeks postgrafting. Jeda 801 image analysis system was used to measure the number and optical density(OD) value of the hippocampal CA1 pyramidal cells stained by Nissl and optical density of synaptophysin immuno-production. The results were analysed by statistical analysis.1. Congo Red staining: the deposition of A 3 was observed close to the injected region on rat brain sections .2. Gros-Bielschowsky silver staining: there were neurofirillary tangles in denaturated neuron .3. Nissl staining : the neurons in control rats were clear and intact. There was no obvious loss of Nissl body in that of Sham-operation rat. The neurons of AD arranged loosely and were difficult to stain. The cells number in control, sham-operation and AD group were 292.0?0.4, 273.8?5.0, 136.8+18.1, respectively. The OD value in control, sham-operation and AD group were 0.24?.02, 0.23+0.01, 0.16+0.02, respectively. There was no significantly difference between that of sham-operation and control (P >0.05) . The number of pyramidal cells and OD value in hippocampalsubfield of AD is significantly lower than that of control (P<0.05) .4. Fluorescence observation: Hoechst33258-labelling grafted cells were yellow, and round. The cells distributed in niddle-path, and hippocampal CAj subfield. The cells in hippocampal CA1 subfield were growing in lump and migrated along the hippocampus.5. PCNA immunohistochemistry: there were many PCNA positive nuclei which appeared brownish, round or oval granules in hippocampal CAi subfield. Plasma and membrane were not stained obviously. None remarkedly PCNA positive cells could be observed in the hippocampus of control and sham-operation groups.6. Synaptophysin immunohistochemistry: the OD value of control, sham-operation, AD, 2-week-transplantation and 4-week-transplantation groups were 0.270?.01, 0.268?.01,...
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