年龄与性别相关的大鼠视皮层树突形态变化

衰老会导致视觉功能的退化,但其潜在的神经机制尚不清楚。通过改良Golgi-Cox染色法,测定了青年雄性、青年雌性及老年雄性与老年雌性4组共20只大鼠视皮层的树突长度和树突棘密度,以研究年龄与性别对视皮层树突形态的影响。结果显示青年雄性大鼠视皮层顶树突、基树突、树突总长度均明显高于青年雌性大鼠,但这种性别差异在老年雌雄组之间并不显著,可能是由于在雄性组之间存在着明显的年龄相关性树突长度减少而在雌性组之间并不存在。青年雄性组的树突棘密度要明显高于青年雌性组,尽管衰老导致了青年雄、雌性组的树突棘密度均明显降低,但老年雄、雌性组的树突棘密度并无显著差异,这可能是由于雄性组的年龄相关性树突密度降低程度要远大于雌性组。由此可见衰老确实能导致视皮层树突形态的退化,这可能是老年性视觉功能衰退的潜在神经机制,但这种退化可能具有一定的性别差异。

Age and Sex-related Dendritic Changes in the Visual Cortex of the Rat

Visual functions undergo an age-related degradation.However,the neural mechanisms underlying these changes are not yet clear.This study was designed to investigate the influence of age and sex on the anatomy of the rat's visual cortex.Dendritic tree extent and spine density were examined in young adult rats(2-3 months)and aged male and female rats(22-24 months)using a modified Golgi-Cox staining method.A sex difference in dendritic branching of the pyramidal cells was found among young adults.However,this difference disappeared during aging,due to a reduction in branching with age for males but not for females.Moreover,the pyramidal cells of young males also have a greater spine density.Although there was a reduction in spine density with age for both sexes,this reduction was more pronounced for males,resulting in a disappearance of sex difference with age.Thus these results suggest that aging could lead to the degeneration of dendrites,which might contribute to the degradation of age-related visual functions.Also the results indicate that age-related degeneration of dendrites is more severe for males than for females.