Lambiase Alessandro, Tirassa Paola, Micera Alessandra, Aloe Luigi, Bonini Stefano
Interdisciplinary Research Center, Laboratory of Ophthalmology, University of Rome Campus Bio-Medico, Italy.
Invest Ophthalmol Vis Sci. 2005 Oct;46(10):3800-6. doi: 10.1167/iovs.05-0301.
Nerve growth factor (NGF) has been shown to inhibit retinal ganglion cell (RGC) degeneration when injected intraocularly in animal models of ocular hypertension, optic nerve transaction, and ischemia. The present study sought to establish the bioavailability of topical NGF to the retina and optic nerve in rats.
Autoradiography was performed to evaluate whether exogenous (125)I-labeled NGF reaches the retina and optic nerve when applied topically to the rat conjunctiva. To quantify NGF levels, a highly specific immunoenzymatic test (ELISA) was performed on the retina, optic nerve, lens, sclera and serum of rats at different time points after administration of NGF (1-500 microg/mL). The physiological activity of topically applied NGF was evaluated by determining retinal brain-derived neurotrophic factor (BDNF) protein and mRNA levels by ELISA and RT-PCR, respectively.
After topical conjunctival administration of NGF, high levels were detected in ocular tissues, including the retina and optic nerve, showing a peak increase 6 hours after administration at a concentration of 200 mug/mL. NGF treatment was associated with an increase in BDNF protein and mRNA levels in rat retina.
These data demonstrate the bioavailability of NGF to the retina and optic nerve in rats when administered topically. These findings justify investigating the clinical effects of topical NGF therapy for treatment of posterior segment diseases.
在高眼压、视神经切断和缺血的动物模型中，眼内注射神经生长因子（NGF）已被证明可抑制视网膜神经节细胞（RGC）变性。本研究旨在确定局部应用NGF对大鼠视网膜和视神经的生物利用度。
进行放射自显影，以评估局部应用于大鼠结膜时，外源性（125）I标记的NGF是否能到达视网膜和视神经。为了量化NGF水平，在给予NGF（1-500μg/mL）后的不同时间点，对大鼠的视网膜、视神经、晶状体、巩膜和血清进行了高特异性免疫酶试验（ELISA）。分别通过ELISA和RT-PCR测定视网膜脑源性神经营养因子（BDNF）蛋白和mRNA水平，评估局部应用NGF的生理活性。
局部结膜给予NGF后，在包括视网膜和视神经在内的眼组织中检测到高水平，在浓度为200μg/mL时，给药后6小时出现峰值增加。NGF治疗与大鼠视网膜中BDNF蛋白和mRNA水平的增加有关。
这些数据证明了局部应用时NGF对大鼠视网膜和视神经的生物利用度。这些发现为研究局部应用NGF治疗眼后段疾病的临床效果提供了依据。
