Department of Ophthalmology and Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, Louisiana 70112, USA.
Invest Ophthalmol Vis Sci. 2010 Feb;51(2):804-10. doi: 10.1167/iovs.09-3641. Epub 2009 Sep 24.
This study was conducted to define whether pigment epithelial-derived growth factor (PEDF), together with docosahexaenoic acid (DHA), enhances the synthesis of neuroprotectin D1 (NPD1) and the regeneration of corneal nerves damaged after surgery.
Corneal stromal dissection was performed in the left eyes of adult New Zealand rabbits treated with DHA+PEDF, PEDF, or DHA for 6 weeks. In vivo confocal images of the corneas were obtained at 2, 4, and 8 weeks, and nerve areas were quantified. At 8 weeks after treatment, corneas were stained with tubulin betaIII antibody, and the epithelial nerve area and the sub-basal and stromal nerve plexus were quantified. At 1 week and 2 weeks after treatment, lipids were extracted from corneas, and the synthesis of NPD1 was analyzed by mass spectrometry. Epithelial cell density was quantified by confocal microscopy 8 weeks after surgery.
In vivo confocal images at 2 and 4 weeks after surgery showed a 2.5-fold increase in corneal nerve area in PEDF+DHA-treated animals compared with control animals. Increased nerve surface areas in epithelia, subepithelia, and stroma were observed in rabbits treated for 8 weeks with PEDF+DHA. PEDF or DHA alone did not produce a significant increase. NPD1 synthesis peaked at 1 week and was four times higher in the PEDF+DHA-treated group than in the controls.
PEDF+DHA promotes the regeneration of corneal nerves. Neurotrophin-mediated NPD1 synthesis is suggested to precede nerve regeneration by demonstration of its accumulation upon addition of DHA and PEDF at earlier time points. Therefore, this signaling mechanism upregulates corneal nerve regeneration and may be targeted in neurotrophic keratitis, dry eye after refractive surgery, and other corneal diseases.
本研究旨在定义色素上皮衍生因子（PEDF）与二十二碳六烯酸（DHA）联合是否能增强神经营养因子 D1（NPD1）的合成和手术后受损角膜神经的再生。
在接受 DHA+PEDF、PEDF 或 DHA 治疗 6 周的成年新西兰兔的左眼进行角膜基质剥离。在 2、4 和 8 周时获取角膜的活体共聚焦图像，并对神经区域进行量化。在治疗 8 周后，用微管蛋白β III 抗体对角膜进行染色，并对上皮神经区域和基底下及基质神经丛进行量化。在治疗后 1 周和 2 周时，从角膜提取脂质，并通过质谱分析 NPD1 的合成。手术后 8 周通过共聚焦显微镜对上皮细胞密度进行量化。
手术后 2 周和 4 周的活体共聚焦图像显示，与对照组相比，PEDF+DHA 治疗组的角膜神经面积增加了 2.5 倍。在接受 PEDF+DHA 治疗 8 周的兔子中，观察到上皮、上皮下和基质中的神经表面积增加。单独使用 PEDF 或 DHA 没有产生显著增加。NPD1 的合成在 1 周时达到峰值，在 PEDF+DHA 治疗组中是对照组的 4 倍。
PEDF+DHA 促进角膜神经再生。神经营养因子介导的 NPD1 合成在 DHA 和 PEDF 早期添加时其积累表明其先于神经再生。因此，这种信号机制上调了角膜神经再生，可能成为神经保护角膜炎、屈光手术后干眼症和其他角膜疾病的治疗靶点。
