Correlation of optical coherence tomography with clinical and histopathological findings in experimental autoimmune uveoretinitis Ivana Gadjanski a, b, c , Sarah K. Williams d, * , Katharina Hein a , Muriel B. Sättler a , Mathias Bähr a , Ricarda Diem d a Department of Neurology, Georg-August University, Robert-Koch Str. 40, 37075 Göttingen, Germany b Department of Biochemistry and Medicine, State University Novi Pazar, Novi Pazar, Serbia c Research and Development Center for Bioengineering, Sretenjskog ustava 27, Kragujevac, Serbia d Department of Neurology, University of the Saarland, Kirrberger Strasse, 66421 Homburg/Saar, Germany article info Article history: Received 26 January 2011 Accepted in revised form 29 April 2011 Available online xxx Keywords: experimental autoimmune uveoretinitis rats in vivo imaging optical coherence tomography histopathology abstract Optical coherence tomography (OCT) is becoming the state-of-the-art method for the non-invasive imaging of a variety of ocular diseases. The aim of this study was to assess the application of OCT for the in vivo monitoring and follow-up of pathological changes during experimental autoimmune uveor- etinitis (EAU) in rats. Initially we established OCT imaging in healthy brown Norway rats and correlated it with retinal histology. Subsequently, we induced EAU and imaged animals by OCT throughout the pre- peak, peak, and post-peak phases of the disease. The sensitivity of OCT imaging was determined by comparison with clinical EAU and histopathology scores obtained ex vivo at several time points throughout the disease course. Our data demonstrate that OCT imaging of the healthy rat retina closely correlates with histological observations and allows the clear visualization of all retinal layers. After induction of EAU, the first pathological changes could be detected by OCT at day (d) 8 post-immunization (p.i.) which corresponded to the time point of clinical disease onset. An increase in retinal thickness (RT) was detected from d10 p.i. onwards which peaked at d16 p.i. and decreased again to near control levels by d20 p.i. We introduce a novel semi-quantitative OCT scoring which correlates with histopathological findings and complements the clinical scores. Therefore, we conclude that OCT is an easily accessible, non-invasive tool for detection and follow-up of histopathological changes during EAU in rats. Indeed, significant differences in RT between different stages of EAU suggest that this OCT parameter is a sensitive marker for distinguishing disease phases in vivo. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Experimental autoimmune uveoretinitis (EAU) is an animal model of autoimmune uveitis, a group of diseases which target the uvea and retina. The main features include retinal and choroidal inflammation, vasculitis, photoreceptor destruction, and ultimately, loss of vision (Caspi et al., 1996; Chan et al., 1990). EAU can be induced in various animal species by active immunization with different retinal antigens, such as retinal soluble antigen or inter- photoreceptor retinoid-binding protein (IRBP) (Adamus and Chan, 2002), or by adoptive transfer of autoreactive T cells (Caspi et al., 1986; Caspi, 2003). Longitudinal in vivo studies of the pathological changes during EAU are necessary for elucidation of the disease-causing mecha- nisms and for monitoring disease onset and progression during therapeutic intervention. In order to perform such examinations, non-invasive, accurate techniques, which allow for repetitive reproducible imaging, should be used. Recently, a number of studies have indicated that optical coherence tomography (OCT) is becoming the state-of-the-art imaging technique for performing high-resolution, cross-sectional ophthalmic imaging (Fujimoto et al., 2000; Li et al., 2001; Grieve et al., 2004; Srinivasan et al., 2006; Ruggeri et al., 2007; Sakata et al., 2009). OCT is especially useful in serial observations of disease development, because it can provide images of tissue in vivo and in real time, without the need for excision and processing of specimens (Fujimoto, 2003). However, up to now, no studies have assessed the efficacy of OCT for monitoring EAU in rodents. In the present study, we used EAU not only as a model for autoimmune disease, but also as * Corresponding author. Department of Neurology, University of the Saarland, Kirrberger Strasse, Building 61.4, 66421 Homburg/Saar, Germany. Tel.: þ49 6841 1647872; fax: þ49 6841 1647801. E-mail address: sarah.williams@uks.eu (S.K. Williams). Contents lists available at ScienceDirect Experimental Eye Research journal homepage: www.elsevier.com/locate/yexer 0014-4835/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.exer.2011.04.012 Experimental Eye Research xxx (2011) 1e9 Please cite this article in press as: Gadjanski, I., et al., Correlation of optical coherence tomography with clinical and histopathological findings in experimental autoimmune uveoretinitis, Experimental Eye Research (2011), doi:10.1016/j.exer.2011.04.012