Three-dimensional optical coherence tomography imaging of retinal sheet implants in live rats

Abstract

a b s t r a c tPurpose: To obtain three-dimensional images from retinal transplants in live animals and evaluate the placement and structural quality of the transplants. Methods: Donor retinal sheets were isolated from E19 fetuses of transgenic rats expressing human alkaline phosphatase (hPAP), and transplanted to the subretinal space of 19-56 days old S334ter-3 rat recipients with fast retinal degeneration (average age at surgery 32 days). A total of 143 rats were imaged 1 day to 2.8 months after surgery, using a Fourier-domain optical coherence tomography (FDOCT) system, with an axial resolution of 3.5 m. The CCD A-line integration time was set at 200 s for better visualization of degenerated retina. After targeting the transplant area, 139 or 199 consecutive slices were scanned. Projection images and movies of the retinal transplant area were computed and later compared with histology. Results: OCT scans identified 137 of 141 transplants as a thickening of the degenerated retina. OCT indicated the laminar structure of the transplants and surgical defects, such as RPE/choroid damage with an accuracy rate between 83 and 99%. Three-dimensional projections showed the transplant position in the retina in relation to the optic disc. Histology of transplants by hPAP and hematoxylin-eosin staining was correlated with the OCT results. Conclusions: Optical coherence tomography is an excellent tool to image retinal layers in a live rat. This procedure helps to evaluate the placement and quality of the transplants in the living eye.

A Novel Approach for Subretinal Implantation of Ultrathin Substrates Containing Stem Cell-Derived Retinal Pigment Epithelium Monolayer

“…This tool is made of stiff materials and consists of a cannula used for loading the substrate. During insertion of the cannula for subretinal placement of the graft, the surgeon cannot see the tip of the cannula; hence, there is the possibility of damaging the neural retina, choroid and even optic nerve [19]. Butterwick et al [20] developed a fork implantation tool containing grooves for subretinal prosthesis implantation in rats, but the above tool may not be suitable for implantation of soft ultrathin substrates.…”

Trophic factors GDNF and BDNF improve function of retinal sheet transplants

“…Rats were selected based on positive surgical outcome (i.e., successful implantation in the subretinal space) and Ocular Coherence Tomography imaging (Seiler et al, 2010a). On the day prior to electrophysiological assessment, each rat was dark-adapted in a Plexiglas cage, which was placed inside a plastic container with an oversized black drapery wrapped around it to prevent any light from reaching inside to the animal.…”

Evaluation of mouse experimental autoimmune uveoretinitis by spectral domain optical coherence tomography

“…However, since Srinivasan et al 15 reported successful OCT imaging of the retina in rats and mice, OCT has been used in studies of rodent models of retinal degeneration and dysfunction 16–18. Seiler et al 19 used OCT to image retinal transplants in live animals and found that OCT helps to evaluate the placement and structural quality of the transplants. In animal models of uveitis, Gadjanski et al 20 first demonstrated the usefulness of OCT for observing progressive changes during the development of EAU in brown Norway rats.…”