节制饮食增强猫视皮层γ-氨基丁酸和脑源性神经营养因子的表达

目的探讨节制饮食对猫初级视皮层内抑制性神经递质γ-氨基丁酸(GABA)和脑源性神经营养因子(BDNF)表达的影响。方法 Nissl染色示初级视皮层分层并用于神经元计数;免疫组织化学方法标记6只猫GABA和BDNF免疫阳性神经元。切片于Olympus光学显微镜下观察摄片,用Image-Pro Express 6.0软件进行细胞计数和免疫阳性反应的吸光度值统计。结果与正常饮食对照猫相比,节制饮食组猫的初级视皮层神经元平均密度无显著变化,GABA免疫阳性神经元密度显著增大,阳性反应的平均吸光度值显著升高;BDNF免疫阳性细胞的密度和阳性反应的平均吸光度值亦明显增大。结论节制饮食能显著增强猫视皮层内GABA和BDNF的表达,这可能对视皮层神经元的结构和功能有保护作用,从而延缓衰老进程。

Dietary restriction enhances γ-aminobutyric acid and brain derived neurotrophic factor expression in the visual cortex of the cat

Objective To explore the effect of DR on the expression of inhibitory neurotransmitter, γ-aminobutyric acid (GABA) and brain derived neurotrophic factor (BDNF) in the primary visual cortex of young cats. Methods Totally 6 cats were wsed in this study. Nissl staining was used for cortical layer identification and cell counting. Immunohistochemical techniques were utilized to label GABA- and BDNF-positive neurons. Sections were observed under an Olympus light microscope and photographed with a digital camera. The cell density and absorbance of immunoreactivity were measured with Image-Pro Express 6.0 softwares.
Results Our results showed that the mean density of Nissl-stained neurons in the primary visual cortex (V1) of the DR group showed no significant difference from that of the control group. However, the mean density of GABA-immunoreactive neurons in each cortical layer of V1 in DR cats was significantly higher than that in control cats. The mean immunoreactive intensity of GABA-positive neurons, as indicated by the average absorbance, increased significantly in DR cats relative to control ones. Accompanied with the elevation of GABA expression, DR enhanced BDNF expression in V1, as indicated by an increased mean density of BDNF-positive neurons and BDNF-immunoreactive average absorbance in DR cats relative to controls. Conclusion These results indicate that dietary restriction leads to a concurrent expression upregulation of GABA and BDNF, which may likely compensate for brain functional degradation during senescence and thus delay aging process.