Center for Integrated Human Brain Science, Brain Research Institute, Niigata University, Niigata, Japan.
Invest Ophthalmol Vis Sci. 2021 Feb 1;62(2):24. doi: 10.1167/iovs.62.2.24.
Details of the posterior eye water dynamics are unclear. Aquaporin-4 (AQP4), a water channel, plays an important role in water dynamics in the central nervous system and is also present in the ocular tissue. The purpose of this study was to reveal the role of AQP4 in the water dynamics of the posterior eye using in vivo JJ vicinal coupling proton exchange (JJVCPE) magnetic resonance imaging (MRI) of AQP4 knockout (KO) mice and their wild-type littermates (controls).
JJVCPE MRI of the eye was performed on five AQP4 KO mice and seven control mice. We assessed the normalized signal intensities of a region of interest (ROI) set in the vitreous body after H217O administration. The results of the two groups were compared using a two-tailed Mann-Whitney U test.
A statistical analysis revealed that the normalized ROI signal intensities at the steady state were significantly lower (P = 0.010, <0.05) in the AQP4 KO mice (mean ± SD, 84.5% ± 2.7%) than the controls (mean ± SD, 88.8% ± 1.9%).
The present study using JJVCPE MRI of the eye demonstrated that retinal AQP4 has a potential role in the regulation of water inflow into the vitreous body. Absence of AQP4 in the KO mice probably induces lower water outflow from the vitreous body. Our results could help clarify the pathogenesis of various ocular diseases.
目前对眼后段水动力的细节仍不清楚。水通道蛋白-4（AQP4）作为一种水通道，在中枢神经系统的水动力学中起着重要作用，也存在于眼部组织中。本研究旨在通过活体 JJ 毗邻偶联质子交换（JJVCPE）磁共振成像（MRI）观察水通道蛋白 4 敲除（KO）小鼠及其野生型同窝仔鼠（对照组），揭示 AQP4 在眼后段水动力学中的作用。
对 5 只 AQP4 KO 小鼠和 7 只对照组小鼠进行眼部 JJVCPE MRI。我们评估了 H217O 给药后玻璃体感兴趣区（ROI）的归一化信号强度。使用双侧曼-惠特尼 U 检验比较两组的结果。
统计学分析显示，在稳态时，AQP4 KO 小鼠（平均值±标准差，84.5%±2.7%）的 ROI 信号强度归一化值明显低于对照组（平均值±标准差，88.8%±1.9%）（P=0.010，<0.05）。
本研究通过眼部 JJVCPE MRI 表明，视网膜 AQP4 可能在调节水流入玻璃体中起作用。KO 小鼠中 AQP4 的缺失可能导致玻璃体的水流出减少。我们的研究结果有助于阐明各种眼部疾病的发病机制。
