鼻腔递送血管活性肠肽对弱视大鼠视皮层脑源性神经营养因子的影响

Effect of nasal administration of vasoactive intestinal peptide on brain-derived neurotrophic factor in the visual cortex of amblyopic rats

摘要:

目的 探索血管活性肠肽（VIP）对形觉剥夺性弱视大鼠视皮层脑源性神经营养因子（BDNF）的影响，探讨弱视治疗的神经保护作用机制。方法 选取3周龄健康SD大鼠36只，随机分为对照组、模型组、治疗组，各12只。采用前爪触地实验测定大鼠视敏度，图形视觉诱发电位（PVEP）测定客观视觉功能；采用Western blotting检测各组大鼠视皮层BDNF表达水平，采用免疫荧光染色观察胶质纤维酸性蛋白（GFAP）和VIP在视皮层中的表达水平和GFAP表达部位，苏木精-伊红（HE）染色观察大鼠视皮层病理学改变。结果 与模型组比较，治疗组视敏度和客观视觉功能均提高（P <0.05），BDNF蛋白表达水平增加（P <0.05），但仍低于对照组（P <0.05）。免疫荧光检测结果显示：GFAP阳性细胞在正常组与弱视组中主要表达在视皮层Ⅰ层和Ⅵ层，且弱视组大鼠视皮层GFAP荧光强度明显低于对照组（P <0.05），治疗组视皮层VIP和GFAP的荧光强度均明显增加（P <0.05）。结论 VIP对弱视大鼠有治疗作用，可能与活化视皮层星形胶质细胞释放BDNF有关。这为弱视的治疗提供了新思路。

Abstract:

Objective To explore the effect of vasoactive intestinal peptide (VIP) on brain-derived neurotrophic factor (BDNF) in the visual cortex of form-deprived amblyopia rats, and to explore the mechanism of neuroprotective effect of amblyopia treatment.Method Thirty-six three-week-old healthy SD rats were selected and randomly divided into control, model and treatment groups, 12 in each group. The visual acuity of rats was measured using the forepaw touchdown test, the objective visual function was measured by pattern visual evoked potentials (PVEP), and the expression level of BDNF in the visual cortex of rats in each group was detected using Western blotting, immunofluorescence staining was used to observe the expression levels of glial fibrillary acidic protein (GFAP) and VIP in the visual cortex and the sites of GFAP expression, pathological changes in the rat visual cortex observed by HE staining.Result Compared with the model group, visual acuity and the objective visual function of the treatment group was significantly improved (P < 0.05), and the BDNF protein expression level was significantly increased (P < 0.05), but still lower than that of the control group (P < 0.05). Immunofluorescence assay results showed: GFAP-positive cells in the normal and amblyopic groups were mainly expressed in layers Ⅰ and Ⅵ of the visual cortex, and the fluorescence intensity of GFAP in the visual cortex of rats in the amblyopic group was significantly lower than that of the control group (P < 0.05), while the fluorescence intensities of VIP and GFAP in the visual cortex of the treated group were significantly increased (P < 0.05).Conclusion VIP has a therapeutic effect on amblyopic rat, which may be related to the release of BDNF from astrocytes in the activated visual cortex, and this study provides new thoughts on the treatment of amblyopia.