Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
BMC Ophthalmol. 2014 Aug 22;14:102. doi: 10.1186/1471-2415-14-102.
Netrin-1 has been reported to promote retinal neovascularization in oxygen-induced retinopathy (OIR). However, netrin-1 receptors, which may mediate netrin-1 action during retinal neovascularization, have not been characterized. In this study, we investigated netrin-1 receptor subtype expression and associated changes in the retinas of mice with OIR.
C57BL/6J mice were exposed to 75±2% oxygen for 5 days and then returned to normal air to induce retinal neovascularization. Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot were used to examine the expression of netrin-1 receptor subtypes in the mouse retinas. Double staining of netrin-1 receptor subtypes and isolectin B4 was used to determine the location of the netrin-1 receptor subtypes in the retinas. Inhibition of retinal neovascularization was achieved by UNC5B shRNA plasmid intravitreal injection. Retinal neovascularization was examined by fluorescein angiography and quantification of preretinal neovascular nuclei in retinal sections.
RT-PCR results showed that, except for UNC5A, netrin-1 receptor subtypes UNC5B, UNC5C, UNC5D, DCC, neogenin, and A2b were all expressed in the retinas of OIR mice 17 days after birth. Western blots showed that only UNC5B expression was significantly increased on that day, and immunofluorescence results showed that only UNC5B and neogenin were expressed in retinal vessels. Treatment of OIR mice with the UNC5B shRNA plasmid dramatically reduced neovascular tufts and neovascular outgrowth into the inner limiting membrane.
UNC5B may promote retinal neovascularization in OIR mice.
已有研究报道，轴突导向因子 netrin-1 可促进氧诱导视网膜病变（OIR）中的视网膜新生血管形成。然而，介导 netrin-1 作用的 netrin-1 受体在视网膜新生血管形成中的作用尚未得到阐明。在本研究中，我们研究了 OIR 小鼠 netrin-1 受体亚型的表达及相关变化。
C57BL/6J 小鼠在 75±2%的氧气中暴露 5 天，然后返回正常空气中以诱导视网膜新生血管形成。采用逆转录聚合酶链反应（RT-PCR）和 Western blot 检测 netrin-1 受体亚型在小鼠视网膜中的表达。采用 netrin-1 受体亚型和异硫氰酸荧光素 B4 双重染色来确定 netrin-1 受体亚型在视网膜中的位置。采用 UNC5B shRNA 质粒玻璃体腔内注射抑制视网膜新生血管形成。通过荧光素血管造影和视网膜切片中视网膜前新生血管核的定量分析来检测视网膜新生血管形成。
RT-PCR 结果显示，除 UNC5A 外，netrin-1 受体亚型 UNC5B、UNC5C、UNC5D、DCC、neogenin 和 A2b 在出生后 17 天的 OIR 小鼠视网膜中均有表达。Western blot 结果显示，仅 UNC5B 的表达在当天显著增加，免疫荧光结果显示，仅 UNC5B 和 neogenin 在视网膜血管中表达。用 UNC5B shRNA 质粒处理 OIR 小鼠可显著减少新生血管丛和新生血管向内界膜的延伸。
UNC5B 可能促进 OIR 小鼠的视网膜新生血管形成。
