S100蛋白在猫初级视皮层中分布及其年龄相关性变化

Distribution of S100 protein and age-related changes of its expression in cat primary visual cortex

比较青年猫和老年猫初级视皮层(primary visual cortex)各层神经元密度,及S100蛋白在初级视皮层各层中的表达与分布,探讨其表达与分布的年龄相关性变化及意义。Nissl法显示初级视皮层各层神经元,免疫组织化学方法(SABC法)示S100蛋白免疫阳性(S100-IR)细胞。光镜下观察、拍照,计数初级视皮层各层中神经元密度和S100-IR细胞密度。S100-IR细胞在初级视皮层中分布呈现区域性特点,白质较灰质密集。与青年猫相比,老年猫初级视皮层神经元密度有下降,老年猫初级视皮层各层S100-IR细胞密度均有不同程度的显著增加(尤其是Ⅱ、Ⅲ、Ⅳ层),胞体较大,阳性较强。动物衰老过程中,初级视皮层存在着明显的星形胶质细胞反应性增生,这种增生可能对灰质层中神经元的丢失有补偿作用,并对维持老年个体初级视皮层形态结构和延缓老年动物初级视皮层功能衰退具有积极意义。

To observe and compare the neuron density and S100 protein expression in the primary visual cortex of young adult and old cats, and to explore the significance of age - related changes of its expression, Nissl stain was used to exhibit the structure and neurons. Immunohistochemical method （SABC method）was applied to exhibit the S100 - IR cells. Under the microscope, the numbers of the neurons and S100 - IR cells in each gray layer were counted and compared. Results showed S100 - IR cells distributed differently in primary visual cortex. The white matter intensived than the gray matter. Compared with that of young adult cats, neurons density in gray layers in old cats decreased. The S100 - IR cells in old cats increased in the density ,especially in layers Ⅱ,Ⅲ.Ⅳ of primary visual cortex, swelled in the body, enhanced in the immunoreactivity. The primary visual cortex astrocytes in old animals had obviously reactive increasing, which might compensate for neuron lose and of positive influences to maintain the morphological structure of primary visual cortex and detain the visual degeneration in senescence.