Tong Chuan-Wang, Wang Zi-Lu, Li Peng, Zhu Hui, Chen Cui-Yun, Hua Tian-Miao
College of Life Science, Anhui Normal University, Wuhu 241000, China;College of Biological Engineering, Wuhu Institute of Technology, Wuhu 241000, China.
College of Life Science, Anhui Normal University, Wuhu 241000, China.
Dongwuxue Yanjiu. 2015 Jan 18;36(1):48-53. doi: 10.13918/j.issn.2095-8137.2015.1.48.
To explore the neural mechanisms mediating aging-related visual function declines, we compared the expressions of brain-derived neurotrophic factor (BDNF) and its high affinity receptor-tyrosine kinase B (TrkB) between young and old adult cats. Nissl staining was used to display neurons in each layer of the lateral geniculate nucleus (LGN). The BDNF- and TrkB receptor-immunoreactive neurons were labeled immunohistochemically, observed under optical microscope and photographed. Their neuronal density and immunoreactive intensity were measured. Results showed that the mean density of the Nissl stained neurons in each LGN layer were comparable between old and young adult cats, and their BDNF and TrkB proteins were widely expressed in all LGN layers. However, compared with young adult cats, both the density and optical absorbance intensity of BDNF- and TrkB-immunoreactive cells in each LGN layer in old cats were significantly decreased. These findings indicate that the decreased expressions of BDNF and TrkB proteins in the LGN may be an important factor inducing the compromised inhibition in the central visual nucleus and the functional visual decline in senescent individuals.
为探究介导衰老相关视觉功能衰退的神经机制，我们比较了年轻成年猫和老年成年猫之间脑源性神经营养因子（BDNF）及其高亲和力受体酪氨酸激酶B（TrkB）的表达。采用尼氏染色法显示外侧膝状体核（LGN）各层中的神经元。用免疫组织化学方法标记BDNF和TrkB受体免疫反应性神经元，在光学显微镜下观察并拍照。测量它们的神经元密度和免疫反应强度。结果显示，老年成年猫和年轻成年猫LGN各层中尼氏染色神经元的平均密度相当，且它们的BDNF和TrkB蛋白在LGN所有层中均广泛表达。然而，与年轻成年猫相比，老年猫LGN各层中BDNF和TrkB免疫反应性细胞的密度和光吸收强度均显著降低。这些发现表明，LGN中BDNF和TrkB蛋白表达的降低可能是导致中枢视觉核团抑制功能受损以及衰老个体视觉功能衰退的一个重要因素。
