Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782, Santiago, Spain.
Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, I+D Farma (GI-1645), Facultad de Farmacia, iMATUS and Health Research Institute of Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782, Santiago, Spain.
Histochem Cell Biol. 2022 Oct;158(4):401-409. doi: 10.1007/s00418-022-02127-8. Epub 2022 Jul 2.
Diabetic retinopathy (DR) is one of the leading causes of blindness in the world. While there is a major focus on the study of juvenile/adult DR, the effects of hyperglycemia during early retinal development are less well studied. Recent studies in embryonic zebrafish models of nutritional hyperglycemia (high-glucose exposure) have revealed that hyperglycemia leads to decreased cell numbers of mature retinal cell types, which has been related to a modest increase in apoptotic cell death and altered cell differentiation. However, how embryonic hyperglycemia impacts cell proliferation in developing retinas still remains unknown. Here, we exposed zebrafish embryos to 50 mM glucose from 10 h postfertilization (hpf) to 5 days postfertilization (dpf). First, we confirmed that hyperglycemia increases apoptotic death and decreases the rod and Müller glia population in the retina of 5-dpf zebrafish. Interestingly, the increase in cell death was mainly observed in the ciliary marginal zone (CMZ), where most of the proliferating cells are located. To analyze the impact of hyperglycemia in cell proliferation, mitotic activity was first quantified using pH3 immunolabeling, which revealed a significant decrease in mitotic cells in the retina (mainly in the CMZ) at 5 dpf. A significant decrease in cell proliferation in the outer nuclear and ganglion cell layers of the central retina in hyperglycemic animals was also detected using the proliferation marker PCNA. Overall, our results show that nutritional hyperglycemia decreases cellular proliferation in the developing retina, which could significantly contribute to the decline in the number of mature retinal cells.
糖尿病视网膜病变（DR）是世界上导致失明的主要原因之一。虽然人们对青少年/成年 DR 的研究有很大的关注，但高血糖对早期视网膜发育的影响研究得较少。最近在营养性高血糖（高葡萄糖暴露）的胚胎斑马鱼模型中的研究表明，高血糖导致成熟视网膜细胞类型的细胞数量减少，这与凋亡细胞死亡的适度增加和细胞分化改变有关。然而，胚胎高血糖如何影响发育中视网膜的细胞增殖仍然未知。在这里，我们将斑马鱼胚胎从受精后 10 小时（hpf）暴露于 50mM 葡萄糖中，直到受精后 5 天（dpf）。首先，我们证实高血糖增加了凋亡死亡，并减少了 5 日龄斑马鱼视网膜中的杆状和 Müller 胶质细胞数量。有趣的是，细胞死亡的增加主要发生在纤毛边缘区（CMZ），那里大多数增殖细胞都位于那里。为了分析高血糖对细胞增殖的影响，我们首先使用 pH3 免疫标记物来量化有丝分裂活性，这表明在 5 日龄时，视网膜中的有丝分裂细胞（主要在 CMZ 中）显著减少。在高血糖动物中，使用增殖标志物 PCNA 还检测到中央视网膜的外核和节细胞层中的细胞增殖显著减少。总的来说，我们的结果表明，营养性高血糖会降低发育中视网膜的细胞增殖，这可能会显著导致成熟视网膜细胞数量的减少。
