Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Curr Eye Res. 2011 Nov;36(11):1028-36. doi: 10.3109/02713683.2011.593110.
To study RhoA activation and the effect of the Rho-kinase inhibitor in the development of retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR).
C57BL/6 mice at postnatal day (P7) were exposed to hyper-oxygen for 5 days and returned to room air for 5 days to induce OIR. RhoA-GTP, an active form of RhoA, in retinas at P12, P13 and P17 was detected. Mice received a single intravitreal injection of Y27632 (5 µM or 50 µM), a Rho-kinase inhibitor, in one eye during the transition from oxygen to room air at P12. Contralateral eyes were used as the control. Fluorescein-conjugated dextran angiography of retinal whole mount was prepared to score features of neovascular retinopathy at P17. The preretinal neovascular nuclei quantification was performed in frozen sections as well to evaluate the neovascularization.
The retinal RhoA-GTP in OIR mice significantly increased from 0.24 ± 0.06 at P12 to 0.38 ± 0.12 at P13 (p < 0.05). The median total retinopathy score of 5.7 was significantly lower in eyes treated with Y27632 than controls (p < 0.001). Significant improvement was found in the specific categories of vascular tufts (p < 0.01) and extraretinal neovascularization (p < 0.05) in treated eyes. Those treated eyes also had a significantly decreased number of neovascular nuclei (p < 0.01).
These results suggest that Rho/Rho-kinase signaling pathways are involved in the early process of hypoxia-induced retinal neovascularization and Y27632 might have therapeutic potential for the treatment of retinal neovascularization.
研究 RhoA 激活及其在氧诱导视网膜病变（OIR）小鼠模型中视网膜新生血管形成中的作用。
将出生后第 7 天（P7）的 C57BL/6 小鼠暴露于高氧中 5 天，然后返回室内空气 5 天以诱导 OIR。在 P12、P13 和 P17 检测视网膜中 RhoA-GTP（RhoA 的活性形式）。在 P12 从高氧转换到室内空气时，一只眼单次玻璃体内注射 Rho-激酶抑制剂 Y27632（5 μM 或 50 μM）。对侧眼作为对照。制备视网膜全铺片的荧光素结合葡聚糖血管造影术，以评估 P17 时新生血管性视网膜病变的特征。还在冷冻切片中对视网膜前新生血管核进行定量，以评估新生血管形成。
OIR 小鼠视网膜 RhoA-GTP 从 P12 时的 0.24±0.06 显著增加到 P13 时的 0.38±0.12（p<0.05）。与对照组相比，Y27632 治疗组的中位数总视网膜病变评分 5.7 显著降低（p<0.001）。在治疗组中，血管丛（p<0.01）和视网膜外新生血管（p<0.05）的特定分类中发现了显著的改善。治疗眼的新生血管核数量也显著减少（p<0.01）。
这些结果表明 Rho/Rho-激酶信号通路参与了缺氧诱导的视网膜新生血管形成的早期过程，Y27632 可能具有治疗视网膜新生血管形成的潜力。
