Using Optical Coherence Tomography and Optokinetic Response As Structural and Functional Visual System Readouts in Mice and Rats

Abstract

Optical coherence tomography (OCT) is a fast, non-invasive, interferometric technique allowing high-resolution retinal imaging. It is an ideal tool for the investigation of processes of neurodegeneration, neuroprotection and neuro-repair involving the visual system, as these often correlate well with retinal changes. As a functional readout, visually evoked compensatory eye and head movements are commonly used in experimental models involving the visual function. Combining both techniques allows a quantitative in vivo investigation of structure and function, which can be used to investigate the pathological conditions or to evaluate the potential of novel therapeutics. A great benefit of the presented techniques is the possibility to perform longitudinal analyses allowing the investigation of dynamic processes, reducing variability and cuts down the number of animals needed for the experiments. The protocol described aims to provide a manual for acquisition and analysis of high quality retinal scans of mice and rats using a low cost customized holder with an option to deliver inhalational anesthesia. Additionally, the proposed guide is intended as an instructional manual for researchers using optokinetic response (OKR) analysis in rodents, which can be adapted to their specific needs and interests.

Distinctive waves of innate immune response in the retina in experimental autoimmune encephalomyelitis

“…Thus, in vivo CSLO measurements are reliable for longitudinal analysis of morphological changes in CX3CR1 GFP/+ retinae. This is the first study to our knowledge employing CSLO for in vivo immune cell imaging in a MS mouse model validating CSLO as a feasible and reliable technique for the longitudinal analysis of retinal immune cell dynamics in mice (44)(45)(46), CSLO empowers the afferent visual system in rodents as a comprehensive model to study the pathophysiology of CNS inflammation (42).…”

The “Neuro-Glial-Vascular” Unit: The Role of Glia in Neurovascular Unit Formation and Dysfunction

“…In addition, functional imaging is allowing the unraveling of NVU functions such as neuronal activity using dynamic calcium imaging ( Chhabria et al, 2018 ) and cellular relationships following metabolic compound exchanges ( Kanow et al, 2017 ). Similarly, optokinetic response measurements are increasingly used to measure visual acuity ( Dietrich et al, 2019 ; Sugita et al, 2020 ). Linked to performing functional imaging, understanding metabolic fluxes, storage, and turnover is crucial in beginning to understand how NVU components communicate and support each other’s function and how they may be disturbed in disease.…”

Neuroprotective Properties of Dimethyl Fumarate Measured by Optical Coherence Tomography in Non-inflammatory Animal Models

“…Automated segmentation was carried out by the Heidelberg Eye Explorer TM software version 1.9.10.0 followed by manual correction of an investigator, blinded for the experimental groups. We calculated the total thickness of the retina (TRT), the inner retinal layers (IRL), consisting of the retinal nerve fiber layer, ganglion cell layer and inner plexiform layer as described elsewhere (19) as well as the outer retinal layers (ORL), consisting of the outer plexiform layer, outer nuclear layer and the photoreceptors. The different layers of the OCT scans are illustrated in Figure 1A.…”