Chong Rachel S, Osborne Andrew, Conceição Raquel, Martin Keith R
Singapore National Eye Centre, Singapore 2Singapore Eye Research Institute, Singapore 3Agency for Science, Technology and Research, Singapore 4John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom.
John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom.
Invest Ophthalmol Vis Sci. 2016 Mar;57(3):842-52. doi: 10.1167/iovs.15-17864.
Platelet-derived growth factor (PDGF) promotes neuronal survival in experimental glaucoma and recruits glial cells that regulate synapses. We investigated the effects of intravitreal PDGF on the inflammatory milieu and retinal synapses in the presence of raised IOP.
Animals with laser-induced IOP elevation received intravitreal injections of either saline or 1.5 μg PDGF. At 7 days, a further intravitreal injection was administered so groups received "PDGF-saline" (n = 15), "PDGF-PDGF" (n = 13), or "saline-saline" (n = 20). Platelet-derived growth factor receptor activation was assessed after 2 weeks using Western blot for PI3 kinase. Immunohistochemistry was performed for markers of synapses in the inner plexiform layer (IPL): PSD-95, GluR1, SY38; RGCs: βIII-tubulin, and glial cells: Iba-1, CD45. Real-time quantitative polymerase chain reaction (qPCR) was performed for Arc, selp, MCP-1, IL-6, IL-10, and CX3CR1 (n = 13).
A single injection of PDGF increased IPL synaptic density in high IOP eyes (PSD-95 = 8.65 ± 0.43, SY38 = 8.68 ± 0.51, GluR1 = 9.03 ± 0.60 puncta/μm3, P < 0.001) and expression of synaptic modulator Arc (6.92 ± 3.71-fold change/control, P < 0.05) in comparison with vehicle (PSD-95 = 4.59 ± 0.41, SY38 = 4.46 ± 0.38, GluR1 = 5.94 ± 0.50 puncta/μm3, Arc = 1.46 ± 0.31-fold/control). This was associated with more resident microglia (8.16 ± 1.34-fold change/control, P < 0.001) and infiltrating monocyte-derived macrophages in the retina as well as increased Selp expression (26.8 ± 14.12-fold change/control, P < 0.05). Optic nerve head (ONH) showed an increased microglia (saline = 1.44 ± 0.13 versus PDGF = 2.23 ± 0.18-fold change/control, P < 0.01) but not infiltrating macrophages. IL-10 expression was significantly increased in PDGF-treated eyes (5.43 ± 0.47-fold change/control, P < 0.05) relative to vehicle (2.51 ± 0.67-fold change/control).
Platelet-derived growth factor increased microglial and monocyte-derived macrophage populations in the eye and protected intraretinal synapses from degeneration in our experimental glaucoma model.
血小板源性生长因子（PDGF）可促进实验性青光眼模型中神经元的存活，并募集调节突触的胶质细胞。我们研究了玻璃体内注射PDGF在眼压升高情况下对炎症环境和视网膜突触的影响。
用激光诱导眼压升高的动物接受玻璃体内注射生理盐水或1.5μg PDGF。在第7天，进行了进一步的玻璃体内注射，因此各实验组分别接受“PDGF-生理盐水”（n = 15）、“PDGF-PDGF”（n = 13）或“生理盐水-生理盐水”（n = 20）。2周后，使用针对PI3激酶的蛋白质印迹法评估血小板源性生长因子受体的激活情况。对内丛状层（IPL）中突触标记物进行免疫组织化学检测：PSD-95、GluR1、SY38；视网膜神经节细胞（RGCs）：βIII-微管蛋白，以及胶质细胞：Iba-1、CD45。对Arc、selp、MCP-1、IL-6、IL-10和CX3CR1进行实时定量聚合酶链反应（qPCR）（n = 13）。
与注射媒介物（PSD-95 = 4.59±0.41，SY38 = 4.46±0.38，GluR1 = 5.94±0.50个/μm3，Arc = 1.46±0.31倍/对照）相比，单次注射PDGF可增加高眼压眼中IPL的突触密度（PSD-95 = 8.65±0.43，SY38 = 8.68±0.51，GluR1 = 9.03±0.60个/μm3，P < 0.001）以及突触调节剂Arc的表达（6.92±3.71倍变化/对照，P < 0.05）。这与视网膜中更多的常驻小胶质细胞（8.16±1.34倍变化/对照，P < 0.001）和浸润的单核细胞衍生巨噬细胞有关，同时Selp表达增加（26.8±14.12倍变化/对照，P < 0.05）。视神经乳头（ONH）显示小胶质细胞增加（生理盐水组 = 1.44±0.13与PDGF组 = 2.23±0.18倍变化/对照，P < 0.01），但没有浸润的巨噬细胞。与注射媒介物组（2.51±0.67倍变化/对照）相比，PDGF治疗组眼中IL-10表达显著增加（5.43±0.47倍变化/对照，P < 0.05）。
在我们的实验性青光眼模型中，血小板源性生长因子增加了眼内小胶质细胞和单核细胞衍生巨噬细胞的数量，并保护视网膜内突触免于退化。
