Angiography reveals novel features of the retinal vasculature in healthy and diabetic mice Samuel McLenachan a, b, * , Aaron Len Magno a, c , David Ramos d , Joana Catita d , Paul G. McMenamin e , Fred Kuanfu Chen a, b, f , Elizabeth Piroska Rakoczy a, c , Jesus Ruberte d, g, h a Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA 6009, Australia b Ocular Tissue Engineering Laboratory, Lions Eye Institute, 2 Verdun Street, Nedlands, WA 6009, Australia c Department of Molecular Ophthalmology, Lions Eye Institute, Nedlands, WA 6009, Australia d Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Animal Health and Anatomy, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Spain e Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia f Ophthalmology Department, Royal Perth Hospital, Wellington Street, Perth, WA 6000, Australia g Department of Animal Health and Anatomy, School of Veterinary Medicine, Universitat Aut onoma de Barcelona, E-08193 Bellaterra, Spain h Interdisciplinary Centre of Research in Animal Health, Faculty of Veterinary Medicine, Universidade de Lisboa, P-1300-477 Lisbon, Portugal article info Article history: Received 5 February 2015 Received in revised form 7 May 2015 Accepted in revised form 22 June 2015 Available online 26 June 2015 Keywords: Retinal vasculature Diabetic retinopathy Angiography Mouse Optical coherence tomography Hyaloid artery Ins2 Akita Akimba abstract The mouse retina is a commonly used animal model for the study of pathogenesis and treatment of blinding retinal vascular diseases such as diabetic retinopathy. In this study, we aimed to characterize normal and pathological variations in vascular anatomy in the mouse retina using fluorescein angiog- raphy visualized with scanning laser ophthalmoscopy and optical coherence tomography (SLO-OCT). We examined eyes from C57BL/6J wild type mice as well as the Ins2 Akita and Akimba mouse models of diabetic retinopathy using the Heidelberg Retinal Angiography (HRA) and OCT system. Angiography was performed on three focal planes to examine distinct vascular layers. For comparison with angiographic data, ex vivo analyses, including Indian ink angiography, histology and 3D confocal scanning laser mi- croscopy were performed in parallel. All layers of the mouse retinal vasculature could be readily visu- alized during fluorescein angiography by SLO-OCT. Blood vessel density was increased in the deep vascular plexus (DVP) compared with the superficial vascular plexus (SVP). Arteriolar and venular ty- pologies were established and structural differences were observed between venular types. Unexpect- edly, the hyaloid artery was found to persist in 15% of C57BL/6 mice, forming anastomoses with peripheral retinal capillaries. Fluorescein leakage was easily detected in Akimba retinae by angiography, but was not observed in Ins2 Akita mice. Blood vessel density was increased in the DVP of 6 month old Ins2 Akita mice, while the SVP displayed reduced branching in precapillary arterioles. In summary, we present the first comprehensive characterization of the mouse retinal vasculature by SLO-OCT fluorescein angiography. Using this clinical imaging technique, we report previously unrecognized variations in C57BL/6J vascular anatomy and novel features of vascular retinopathy in the Ins2 Akita mouse model of diabetes. Crown Copyright © 2015 Published by Elsevier Ltd. All rights reserved. 1. Introduction Alterations in the retinal vasculature are a common feature in ocular pathology arising from a diverse number of causes, including diabetic retinopathy (DR), retinopathy of prematurity, retinal vein occlusion, macular telangiectasia and sickle cell disease (Cheung et al., 2010; Robinson and Halpern, 1992; Sarks et al., 1997; Serjeant et al., 1986; Smith, 2003). Small animal models of retinal Abbreviations: DR, diabetic retinopathy; DVP, deep vascular plexus; EGFP, enhanced green fluorescent protein; HRA, Heidelberg Spectralis Retinal Angiog- raphy; IVP, intermediate vascular plexus; PBS, phosphate buffered saline; PDGF-Rb, platelet derived growth factor-receptor-b; SLO-OCT, scanning laser ophthalmoscopy and optical coherence tomography; SMA, smooth muscle actin; SVP, superficial vascular plexus; VEGF, vascular endothelial growth factor; WT, wild type. * Corresponding author. Lions Eye Institute, 2 Verdun Street, Nedlands, WA 6009, Australia. E-mail address: smclenachan@lei.org.au (S. McLenachan). Contents lists available at ScienceDirect Experimental Eye Research journal homepage: www.elsevier.com/locate/yexer http://dx.doi.org/10.1016/j.exer.2015.06.023 0014-4835/Crown Copyright © 2015 Published by Elsevier Ltd. All rights reserved. Experimental Eye Research 138 (2015) 6e21