Matsuura T, Yamagishi S, Kodama Y, Shibata R, Ueda S, Narama I
Department of Pathology, Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan.
Int J Tissue React. 2005;27(2):59-62.
We have previously shown that the peak latency of oscillatory potential (OP), the earliest electroretinographic manifestation of diabetic retina, was prolonged in Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model of non-insulin-dependent diabetes. These observations suggest that retinal neuronal dysfunction revealed by the OP abnormality in the electroretinogram takes place prior to the angiopathic diabetic changes in this animal model. However whether acellular capillaries and pericyte ghosts, one of the histopathological hallmarks of early diabetic retinopathy in humans, could occur in OLETF rat remains to be elucidated. In the present study, we first prepared the retinal trypsin digests of OLETF and control Long-Evans Tokushima Otsuka (LETO) rats at 45 weeks old and then compared the number of acellular capillaries and pericyte ghosts in the retinas of OLETF rats with that in LETO rats. Blood glucose levels were higher in the OLETF rats than those in LETO rats. Retinal capillaries of OLETF rats were found to remain morphologically normal and pericyte ghosts were barely detectable. There was no difference in the number of acellular capillaries in the retinas between OLETF and LETO rats. The present study indicates that acellular capillaries and pericyte ghosts, the characteristic morphological changes in early diabetic retinopathy, are not accelerated in OLETF rats. Our data suggest that OLETF rat is not a suitable animal model for the study of angiopathic diabetic retinopathy.
我们之前已经表明，振荡电位（OP）的峰值潜伏期是糖尿病视网膜最早的视网膜电图表现，在非胰岛素依赖型糖尿病模型大冢长-艾氏-德岛肥胖（OLETF）大鼠中会延长。这些观察结果表明，视网膜电图中OP异常所揭示的视网膜神经元功能障碍在该动物模型的糖尿病血管病变之前就已发生。然而，人类早期糖尿病视网膜病变的组织病理学特征之一——无细胞毛细血管和周细胞鬼影是否会在OLETF大鼠中出现仍有待阐明。在本研究中，我们首先制备了45周龄的OLETF大鼠和对照长-艾氏-德岛大冢（LETO）大鼠的视网膜胰蛋白酶消化物，然后比较了OLETF大鼠视网膜中无细胞毛细血管和周细胞鬼影的数量与LETO大鼠的数量。OLETF大鼠的血糖水平高于LETO大鼠。发现OLETF大鼠的视网膜毛细血管在形态上保持正常，几乎检测不到周细胞鬼影。OLETF大鼠和LETO大鼠视网膜中无细胞毛细血管的数量没有差异。本研究表明，无细胞毛细血管和周细胞鬼影，即早期糖尿病视网膜病变的特征性形态学变化，在OLETF大鼠中不会加速出现。我们的数据表明，OLETF大鼠不是研究糖尿病血管性视网膜病变的合适动物模型。
