Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan.
BMC Complement Altern Med. 2018 Jun 22;18(1):193. doi: 10.1186/s12906-018-2256-z.
Presumably, progression of developmental retinal vascular disorders is mainly driven by persistent ischemia/hypoxia. An investigation into vision-threatening retinal ischemia remains important. Our aim was to evaluate, in relation to retinal ischemia, protective effects and mechanisms of Dendrobium nobile Lindley (DNL) and its bibenzyl component moscatilin. The therapeutic mechanisms included evaluations of levels of placental growth factor (PLGF) and Norrie disease protein (NDP).
An oxygen glucose deprivation (OGD) model involved cells cultured in DMEM containing 1% O, 94% N and 0 g/L glucose. High intraocular pressure (HIOP)-induced retinal ischemia was created by increasing IOP to 120 mmHg for 60 min in Wistar rats. The methods included electroretinogram (ERG), histopathology, MTT assay and biochemistry.
When compared with cells cultured in DMEM containing DMSO (DMSO+DMEM), cells subjected to OGD and pre-administrated with DMSO (DMSO+OGD) showed a significant reduction in the cell viability and NDP expression. Moreover, cells that received OGD and 1 h pre-administration of 0.1 μM moscatilin (Pre-OGD Mos 0.1 μM) showed a significant counteraction of the OGD-induced decreased cell viability. Furthermore, compared with the DMSO+OGD group (44.54 ± 3.15%), there was significant elevated NDP levels in the Pre-OGD Mos 0.1 μM group (108.38 ± 29.33%). Additionally, there were significant ischemic alterations, namely reduced ERG b-wave, less numerous retinal ganglion cells, decreased inner retinal thickness, and reduced/enhanced amacrine's ChAT/Müller's GFAP or vimentin immunolabelings. Moreover, there were significantly increased protein levels of HIF-1α, VEGF, PKM2, RBP2 and, particularly, PLGF (pg/ml; Sham vs. Vehicle: 15.11 ± 1.58 vs. 39.53 ± 5.25). These ischemic effects were significantly altered when 1.0 g/Kg/day DNL (DNL1.0 + I/R or I/R+ DNL1.0) was applied before and/or after ischemia, but not vehicle (Vehicle+I/R). Of novelty and significance, the DNL1.0 action mechanism appears to be similar to that of the anti-PLGF Eylea [PLGF (pg/ml); DNL1.0 vs. Eylea+I/R: 19.93 ± 2.24 vs. 6.44 ± 0.60].
DNL and moscatilin are able to protect against retinal ischemic/hypoxic changes respectively by downregulating PLGF and upregulating NDP. Progression of developmental retinal vascular disorders such as Norrie disease due to persistent ischemia/hypoxia might be thus prevented.
发育性视网膜血管疾病的进展主要归因于持续的缺血/缺氧。对威胁视力的视网膜缺血的研究仍然很重要。我们的目的是评估铁皮石斛（DNL）及其联苄成分莫斯卡汀在视网膜缺血方面的保护作用和机制。治疗机制包括评估胎盘生长因子（PLGF）和诺里病蛋白（NDP）的水平。
采用含 1% O、94% N 和 0 g/L 葡萄糖的 DMEM 培养细胞的氧葡萄糖剥夺（OGD）模型。通过在 Wistar 大鼠中升高眼压（IOP）至 120 mmHg 60 min 来建立高眼内压（HIOP）诱导的视网膜缺血。方法包括视网膜电图（ERG）、组织病理学、MTT 测定和生物化学。
与在含有 DMSO 的 DMEM 中培养的细胞（DMSO+DMEM）相比，在 OGD 下培养并预先给予 DMSO（DMSO+OGD）的细胞活力和 NDP 表达显著降低。此外，接受 OGD 和 1 h 前给予 0.1 μM 莫斯卡汀（Pre-OGD Mos 0.1 μM）的细胞表现出对 OGD 诱导的细胞活力降低的显著拮抗作用。此外，与 DMSO+OGD 组（44.54 ± 3.15%）相比，Pre-OGD Mos 0.1 μM 组的 NDP 水平显著升高（108.38 ± 29.33%）。此外，出现明显的缺血性改变，即 ERG b 波降低、视网膜神经节细胞数量减少、内视网膜厚度减少以及 ChAT/Müller 的 GFAP 或波形蛋白免疫标记物减少/增强。此外，HIF-1α、VEGF、PKM2、RBP2 的蛋白水平显著升高，尤其是 PLGF（pg/ml；Sham 与 Vehicle：15.11 ± 1.58 与 39.53 ± 5.25）。当在缺血前和/或缺血后给予 1.0 g/Kg/天的 DNL（DNL1.0+I/R 或 I/R+DNL1.0）时，这些缺血效应明显改变，但给予载体时则没有改变（Vehicle+I/R）。具有新颖性和重要意义的是，DNL 的作用机制似乎与抗 PLGF 的 Eylea 相似[PLGF（pg/ml）；DNL1.0 与 Eylea+I/R：19.93 ± 2.24 与 6.44 ± 0.60]。
DNL 和莫斯卡汀分别通过下调 PLGF 和上调 NDP 来保护视网膜免受缺血/缺氧变化的影响。由于持续的缺血/缺氧，发育性视网膜血管疾病（如诺里病）的进展可能会因此得到预防。
