Development of high-resolution digital fundus camera for small animals and application of it to studies on analysis of responsiveness of retinal blood vessels

小动物高分辨率数码眼底相机的研制及其在视网膜血管反应性分析研究中的应用

• 批准号: 12672116
• 负责人: ISHII Kunio
• 金额: $ 2.5万
• 依托单位: Kitasato University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12672116/
• 关键词: rat; retinal arteriole; retinal venule; diabetes mellitus; hypertension; fundus camera; drug responsiveness; β-adrenergic receptors; β-アドレナリン受容体; 網膜細動静脈; 血管径; 血管収縮薬; 高血圧; 血管拡張薬

We succeeded in developing a high-resolution digital fundus camera for small experimental animals by coupling the objective lens of Scalar VMS-170 digital video camera and the body of Nikon D1 or D1x single-lens reflex digital still camera. A special connecting tube was made to connect both devices, to bring the focal plain of the objective lens just on the CCD with a concave lens and to illuminate the fundus with light guided with glass fibers from a lighting unit. With this camera, we were able to capture clear digital images of rat fundus composed of 2.7- or 5.5-million pixels. Resolving power of the camera was estimated less than 2μm indicating enough capacity for measurement of diameters of rat retinal blood vessels.Responsiveness of rat retinal arterioles and venules to adrenergic agents, angiotensin II, serotonin, nitrovasodilators and calcium antagonists was examined under tetrodotoxin treatment and artificial ventilation. We found that, In streptozotocin-induced diabetic rats, dilator responses to β-adrenergic stimulation of retinal arterioles were greatly impaired, although responses to other agents were little affected.In stroke-prone spontaneously hypertensive rats (SHR-SP), retinal arterioles were narrow by about 30% and dilator responses to nicardipine and fasudil of these blood vessels were augmented. As causes of this phenomenon, enhanced influx of Ca^<2+> and augmented Ca^<2+> sensitivity of vascular smooth muscles due to activation of the Rho kinase in retinal arterioles of SHR-SP were suggested. No apparent change was observed in shape or drug responsiveness in retinal venules of SHR-SP.

通过将Scalar VMS-170数码摄像机的物镜与尼康D1或D1x单镜反光数码相机机身相结合，我们成功开发了用于小型实验动物的高分辨率数码眼底相机。制作了一个特殊的连接管来连接两个设备，使物镜的焦平面正好位于带有凹透镜的 CCD 上，并用来自照明单元的玻璃纤维引导的光照亮眼底。使用这款相机，我们能够捕捉到由 2.7 或 550 万像素组成的清晰的大鼠眼底数字图像。相机的分辨率估计小于2μm，表明有足够的能力测量大鼠视网膜血管的直径。在河豚毒素治疗和人工通气下检查大鼠视网膜小动脉和小静脉对肾上腺素能药物、血管紧张素II、血清素、硝基血管扩张剂和钙拮抗剂的反应性。我们发现，在链脲佐菌素诱导的糖尿病大鼠中，尽管对其他药物的反应几乎不受影响，但对视网膜小动脉β-肾上腺素刺激的扩张剂反应受到极大损害。在易发生中风的自发性高血压大鼠（SHR-SP）中，视网膜小动脉狭窄约30％，并且这些血管对尼卡地平和法舒地尔的扩张剂反应增强。作为该现象的原因，认为由于SHR-SP的视网膜小动脉中的Rho激酶的活化，Ca ^ 2+ 的流入增加以及血管平滑肌的Ca ^ 2+ 敏感性增强。 SHR-SP 视网膜小静脉的形状或药物反应性未观察到明显变化。