Investigation of Senile dementia of Alzheimer type(SDAT) in brain transplantation of rats.

Meynert基底核胆碱能神经元的破坏和/或丧失与老年痴呆症（SDAT）有关。本研究旨在探讨老龄大鼠和胚胎脑组织移植成年大鼠后胆碱能神经元及其回路的形态学和组织化学变化。在第一年，(1)在单克隆抗体对胆碱乙酰转移酶（ChAT）的免疫组化研究中，ChAT阳性神经元在腹侧pallidum（VP）移植物中表现出与宿主VP相同的形态学特征。(2)电镜观察显示移植物神经回路发育良好，并形成突触接触。(3)移植物与宿主组织交界区毛细血管发育。第二年，老龄大鼠（25月龄）与青年大鼠（2月龄）VP chat阳性神经元形态比较。老年组chat -阳性神经元的大小、树突数量、树突交点和树突长度均明显减少。这些结果表明，大鼠VP胆碱能神经元也受到衰老的影响。在最后一年，我们改进了乙酰胆碱酯酶（AChE）组织化学方法来观察移植物中的神经元细胞体和纤维。此外，将在侧脑室移植一年的VP组织与短期移植的VP组织进行比较。

Destruction and/or loss of cholinergic neurons in the nucleus basalis of Meynert are involved in Senile dementia of Alzheimer type(SDAT). The aim of the present study was to investigate the morphological and histochemical changes in cholinergic neurons and their circuitry in the aged rats and fetal brain tissues transplanted into the adult rats. In the first year, (1)in the immunohisto-chemical study of choline acetyltransferase(ChAT) using a monoclonal antibody, the ChAT-positive neurons in the ventral pallidum(VP) grafts showed morphological features identical to those in the host VP. (2)Electron microscopic observation revealed that neural circuits were well developed and formed synaptic contacts in the grafts. (3)Blood capillaries were developed in the junctional area between grafts and host tissue.In the second year, the morphology of ChAT-positive neurons of VP in aged rats(25 month-old) was compared to those in young adult rats(2 month-old). The size, the number of dendrites, the dendritic intersection and the length of dendrites of ChAT-positive neurons were significantly reduced in the aged group. These findings suggested that the rat VP cholinergic neurons were also affected by aging.In the final year, we modified acetylcholinesterase(AChE) histo chemical procedure to observe neuronal cell bodies and fibers in the transplants. Moreover, VP tissues transplanted in the lateral ventricle for one year will be compared to the transplants processed a short term.