Experimental Research Center, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China.
Invest Ophthalmol Vis Sci. 2010 Jun;51(6):2986-92. doi: 10.1167/iovs.09-4151. Epub 2010 Jan 13.
To determine sonic hedgehog (Shh) expression and whether it exerts neuroprotective effects on retinal ganglion cells (RGCs) in a rat chronic ocular hypertension model.
Intraocular pressure (IOP) elevation in adult rat was induced by episcleral vein cautery. Retinal expression of Shh protein and mRNA was determined by immunohistochemistry, Western blot analysis, and real-time PCR. Exogenous Shh and its inhibitor cyclopamine were intravitreally injected to examine their effects on RGC survival after ocular hypertension by the counting of retrograde DiI-labeled RGCs. Shh pathway components mediating neuroprotective effects were characterized using Western blot analysis and real-time PCR.
Shh was mainly detected in the RGCs in normal adult rat. Retinas from the elevated IOP group had 2.1- to 4.4-fold greater Shh expression than control retinas (P < 0.05). Shh promoted RGC survival at 2 and 4 weeks after IOP elevation in a dose-dependent manner, resulting in a loss of only 4.54% +/- 0.36% RGCs at 2 weeks (P < 0.01; vs. PBS-treated groups). In contrast, cyclopamine increased RGC loss. Protein and mRNA levels of the Shh signal transducer Smo and the downstream transcription factor Gli1 were significantly upregulated in RGCs after chronic ocular hypertension or intravitreal injection of Shh.
Shh and Smo are upregulated in a time-dependent manner in retinas exposed to ocular hypertension, and Shh has neuroprotective effects on damaged RGCs in a rat chronic hypertension model. Shh may exert neuroprotective effects by relieving the inhibition of Smo and subsequently activating Gli1.
确定 sonic hedgehog（Shh）在大鼠慢性眼压模型中的表达及其对视网膜神经节细胞（RGCs）是否具有神经保护作用。
通过巩膜静脉烧灼术升高成年大鼠眼内压。通过免疫组织化学、Western blot 分析和实时 PCR 测定 Shh 蛋白和 mRNA 的视网膜表达。通过逆行 DiI 标记的 RGCs 计数，将外源性 Shh 及其抑制剂环巴胺眼内注射，观察其对眼压升高后 RGC 存活的影响。通过 Western blot 分析和实时 PCR 鉴定介导神经保护作用的 Shh 途径成分。
Shh 在正常成年大鼠的 RGCs 中主要被检测到。与对照组相比，IOP 升高组的视网膜 Shh 表达增加了 2.1-4.4 倍（P < 0.05）。Shh 以剂量依赖性方式促进 IOP 升高后 2 周和 4 周的 RGC 存活，导致 2 周时仅损失 4.54% +/- 0.36%的 RGC（P < 0.01；与 PBS 处理组相比）。相比之下，环巴胺增加了 RGC 的损失。慢性眼压或 Shh 眼内注射后，RGC 中的 Shh 信号转导 Smo 和下游转录因子 Gli1 的蛋白和 mRNA 水平均显著上调。
暴露于眼压升高的视网膜中，Shh 和 Smo 呈时间依赖性上调，Shh 在大鼠慢性高血压模型中对受损的 RGC 具有神经保护作用。Shh 可能通过解除对 Smo 的抑制作用，随后激活 Gli1，从而发挥神经保护作用。
