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/或丢失与阿尔茨海默型老年性痴呆(SDAT)有关。本研究的目的是观察老年大鼠和胎鼠脑组织移植到成年大鼠体内后胆碱能神经元及其环路的形态和组织化学变化。在第一年，(1)在胆碱乙酰转移酶(ChAT)的免疫组织化学研究中，移植的腹侧苍白球(VP)的ChAT阳性神经元的形态特征与宿主VP的相同。(2)电子显微镜观察，移植物内神经环路发达，形成突触接触。(3)在移植物与宿主组织交界处形成毛细血管。第二年，比较老年大鼠(25月龄)与青年成年大鼠(2月龄)VP区ChAT阳性神经元的形态。老年组ChAT阳性神经元的大小、树突数目、树突交叉点和树突长度均明显小于老年组。这些结果表明，大鼠VP胆碱能神经元也受到年龄的影响。在最后一年，我们改进了乙酰胆碱酯酶(AChE)组织化学程序来观察移植细胞中的神经元胞体和纤维。此外，在侧脑室移植一年的VP组织将与短期处理的移植进行比较。

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.