磨牙缺失对老年大鼠大脑边缘叶胆碱能纤维密度的影响

目的探讨磨牙缺失时老年大鼠大脑边缘叶皮质胆碱能纤维密度的影响。方法选用SD大鼠40只，分为老年缺牙组、老年对照组（18个月龄）和青年缺牙组、青年对照组（3个月龄）。缺牙组大鼠拔除左侧磨牙，2个月后大脑定位取材，乙酰胆碱脂酶（AChE）组化染色，光镜下观察海马CA1区、齿状回、扣带回前区和后区胆碱能纤维密度。结果老年拔牙组海马CA1区辐射层、齿状回分子层AChE阳性纤维密度明显少于老年对照组（P〈0．05）；老年拔牙组扣带回后区第Ⅳ层AChE阳性纤维密度明显少于老年对照组（P〈0.01）。结论单侧磨牙缺失可加速老年机体边缘叶胆碱能系统退变，这可能是缺牙引起老年性学习记忆减退机制之一。

The effect of molar-loss on the density of cholinergic fibers in limbic lobe of aged rats

Objective To explore the effect of molarless on the density of cholinergic fiber in the limbic lobe of aged rats. Methods Forty rats were divided into molar-extraction aged group and control aged group （18 months）, molar-extraction young group and control young group （3 months）. For molar-extraction groups, the left molars were extracted. 2 months after teeth extraction, ACHE- positive fibers within hippocampal area CA1, dentate gyrus, anterior and posterior cingulate gyrus of all experimental animals were quantitatively analyzed. Results The density of AChE-positive fibers in radiatum layer of CA1 and molecular layer of dentate gyrus in molars extraction aged groups were significantly lower than those in control aged groups （P 〈 0.05）, The density of AChE-positive fibers in inner granular layer of posterior cingulate gyrus in molars extraction aged groups were significantly lower than those in control aged group （P 〈 0.01 ）, Conclusion Unilateral loss of molar can accelerate degeneration of cholinergic system in limbie lobe of aged rats. This may be one of the mechanisms of aged learning and memory deficit caused by edentia.