Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China.
National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China.
Kaohsiung J Med Sci. 2023 Sep;39(9):916-926. doi: 10.1002/kjm2.12722. Epub 2023 Jun 20.
The blood-retinal barrier (BRB), homeostasis, neuronal integrity, and metabolic processes are all directly influenced by Müller cells, the most important retinal glial cells. We isolated primary Müller cells from Sprague-Dawley (SD) neonatal rats and treated them with glucose at varying doses. CCK-8 was used to quantify cellular viability, and a TUNEL assay was performed to detect cell apoptosis. ELISA, immunofluorescence, and western blotting were used to assess cAMP/PKA/CREB signaling, Kir4.1, AQP4, GFAP, and VEGF levels, respectively. H&E staining was used to examine histopathological alterations in diabetic retinopathy (DR)-affected retinal tissue in rats. As glucose concentration increases, gliosis of Müller cells became apparent, as evidenced by a decline in cell activity, an increase in apoptosis, downregulation of Kir4.1 level, and overexpression of GFAP, AQP4, and VEGF. Treatments with low, intermediate, and high glucose levels led to aberrant activation of cAMP/PKA/CREB signaling. Interestingly, blocking cAMP and PKA reduced high glucose-induced Müller cell damage and gliosis by a significant amount. Further in vivo results suggested that cAMP or PKA inhibition significantly improved edema, bleeding, and retinal disorders. Our findings showed that high glucose exacerbated Müller cell damage and gliosis via a mechanism involving cAMP/PKA/CREB signaling.
血视网膜屏障 (BRB)、内环境平衡、神经元完整性和代谢过程都直接受到 Müller 细胞的影响，Müller 细胞是最重要的视网膜神经胶质细胞。我们从 Sprague-Dawley (SD) 新生大鼠中分离出原代 Müller 细胞，并以不同剂量的葡萄糖进行处理。用 CCK-8 检测细胞活力，用 TUNEL 检测细胞凋亡。分别用 ELISA、免疫荧光和 Western blot 检测 cAMP/PKA/CREB 信号、Kir4.1、AQP4、GFAP 和 VEGF 的水平。用 H&E 染色观察糖尿病视网膜病变 (DR)大鼠视网膜组织的组织病理学改变。随着葡萄糖浓度的增加，Müller 细胞的神经胶质增生变得明显，表现为细胞活性下降、凋亡增加、Kir4.1 水平下调以及 GFAP、AQP4 和 VEGF 的过表达。用低、中、高浓度的葡萄糖处理会导致 cAMP/PKA/CREB 信号的异常激活。有趣的是，阻断 cAMP 和 PKA 会显著减少高葡萄糖诱导的 Müller 细胞损伤和神经胶质增生。进一步的体内研究结果表明，cAMP 或 PKA 抑制可显著改善水肿、出血和视网膜病变。我们的研究结果表明，高葡萄糖通过 cAMP/PKA/CREB 信号通路加剧 Müller 细胞损伤和神经胶质增生。
