脑内注射Aβ_(25-35)未见对大鼠隔-海马胆碱能系统的毒性作用

ADMINISTRATION OF Aβ 25 35 IS NOT NEUROTOXIC TO THE SEPTO HIPPOCAMPAL CHOLINERGIC SYSTEM IN RATS

本文运用ＣｈＡＴ 免疫组织化学方法和ＡＣｈＥ组织化学方法观察了Ａβ２５３５对大鼠隔海马胆碱能系统的影响。结果如下：Ａβ２５３５注射入内侧隔核，存活１４ ｄ，内侧隔核ＣｈＡＴ 阳性细胞和其支配靶区海马ＡＣｈＥ 阳性纤维的形态和数量未见明显变化；Ａβ２５３５注射入海马，存活１４ ｄ，注射点附近ＡＣｈＥ纤维和同侧内侧隔核ＣｈＡＴ 阳性细胞也未见明显变化。上述结果显示，在目前实验条件下，脑内注射Ａβ２５３５对大鼠隔海马胆碱能系统没有明显影响。结合文献讨论，本文作者认为：Ａβ对中枢胆碱能系统是否具有毒性作用还有待进一步探索。

The β amyloid protein(Aβ) is the primary constituent of senile plaques in Alzheimer's disease(AD). Recent evidences have demonstrated the neurotoxicity of Aβ in vitro and in vivo. The selective degeneration of neurons in the septo hippocampal cholinergic system is one of the neuropathological features of AD. Nevertheless, the reports concerning effects of Aβ on the septo hippocampal cholinergic system were relatively few, especially, it is fairly poor in the morphological field. In this article, it was evaluated whether Aβ exerts neurotoxic effects on the septo hippocampal cholinergic system by choline acetyltransferase(ChAT) immunohistochemical and acetylcholinesterase(AChE) histochemical methods. The results were as follows: Microinjection of Aβ 25 35 into the medial septal nucleus of rats didn't result in any change in the morphology and number of the ChAT positive neurons in the medial septal nucleus and AChE positive fibers in the hippocampus after a 14 day survival time as compared with control groups, nor did microinjection of Aβ 25 35 into the hippocampus. These results suggest, under the condition studied, we don't observe any effect of Aβ 25 35 on the septo hippocampal cholinergic system in rats. It remains to be further investigated whether Aβ is neurotoxic in different laboratory conditions and animal species and self protection mechanism. (Figures 1～6 on plate 49)