Thrombosis and Atherosclerosis Research Institute, McMaster University, Hamilton, Ontario, Canada.
Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada.
Invest Ophthalmol Vis Sci. 2020 Aug 3;61(10):49. doi: 10.1167/iovs.61.10.49.
Recent evidence suggests that there is a correlation between the micro- and macrovascular complications of diabetes mellitus. The aim of this study is to investigate the molecular mechanisms by which diabetes promotes the development of microvascular disease (diabetic retinopathy [DR]) through characterization of the effects of hyperglycemia in the retina of mouse models of diabetic atherosclerosis.
Hyperglycemia was induced in apolipoprotein E-deficient (ApoE-/-) mice, a model of accelerated atherosclerosis, either through streptozotocin (STZ) injection or introduction of the Ins2Akita mutation (ApoE-/-Ins2+/Akita). Another subset of ApoE-/- mice was supplemented with glucosamine (GlcN). To attenuate atherosclerosis, subsets of mice from each experimental group were treated with the chemical chaperone, 4-phenylbutyric acid (4PBA). Eyes from 15-week-old mice were either trypsin digested and stained with periodic acid-Schiff (PAS) or frozen for cryostat sectioning and immunostained for endoplasmic reticulum (ER) stress markers, including C/EBP homologous protein (CHOP) and 78-kDa glucose-regulated protein (GRP78). PAS-stained retinal flatmounts were analyzed for microvessel density, acellular capillaries, and pericyte ghosts.
Features of DR, including pericyte ghosts and reduced microvessel density, were observed in hyperglycemic and GlcN-supplemented mice. Treatment with 4PBA reduced ER stress in the retinal periphery and attenuated DR in the experimental groups.
Mouse models of diabetic atherosclerosis show characteristic pathologies of DR that correlate with atherosclerosis. The increased magnitude of these changes and responses to 4PBA in the peripheral retina suggest that future studies should be aimed at assessing regional differences in mechanisms of ER stress-related pathways in these mouse models.
最近的证据表明，糖尿病的微血管和大血管并发症之间存在相关性。本研究旨在通过研究高血糖对糖尿病动脉粥样硬化小鼠模型视网膜的影响，来探讨糖尿病促进微血管疾病（糖尿病视网膜病变[DR]）发展的分子机制。
通过链脲佐菌素（STZ）注射或引入胰岛素 2 基因 Akita 突变（ApoE-/-Ins2+/Akita），在载脂蛋白 E 缺陷（ApoE-/-）小鼠（加速动脉粥样硬化模型）中诱导高血糖。另一组 ApoE-/-小鼠用氨基葡萄糖（GlcN）补充。为了减轻动脉粥样硬化，从每个实验组的亚组小鼠中用化学伴侣 4-苯丁酸（4PBA）治疗。15 周龄小鼠的眼睛或用胰蛋白酶消化并用过碘酸-Schiff（PAS）染色，或冷冻用于冰冻切片和免疫染色内质网（ER）应激标志物，包括 C/EBP 同源蛋白（CHOP）和 78kDa 葡萄糖调节蛋白（GRP78）。对 PAS 染色的视网膜平片进行微血管密度、无细胞毛细血管和周细胞幽灵的分析。
在高血糖和 GlcN 补充的小鼠中观察到 DR 的特征性病变，包括周细胞幽灵和微血管密度降低。用 4PBA 治疗可减少视网膜周边 ER 应激，并减轻实验组的 DR。
糖尿病动脉粥样硬化小鼠模型显示出与动脉粥样硬化相关的 DR 特征性病变。这些变化的幅度增加以及对 4PBA 的反应在周边视网膜中表明，未来的研究应该旨在评估这些小鼠模型中 ER 应激相关途径的区域差异的机制。
