Retinal transplants evaluated by optical coherence tomography in photoreceptor degenerate rats

Abstract

Optical coherence tomography (OCT), a non-invasive method, was used for qualitative assessment of fetal retinal sheet transplants by noninvasive imaging. Rhodopsin-mutant S334ter-line-3 rats with fast retinal degeneration (28-37-day old) were transplanted with fetal retinal sheets from embryonic day (E) 18-19 pigmented normal rats. Retinal thickness measurements from transplanted (n = 51), no surgery control (n = 8), and normal pigmented rat eyes (n = 6) were obtained using a Zeiss stratus OCT-3 scanning instrument. Frozen retinal sections were stained with hematoxylin/eosin. S334ter-line-3 rats showed significant reduction in OCT retinal thickness (p < 0.001) compared to normal pigmented rats at the age of 21 days. In 62% of the transplanted rats, OCT scanning revealed the presence of a subretinal graft, which was confirmed by subsequent histology. Retinal thickness in the transplant area was significantly increased compared to the area outside the transplant and to non-transplanted eyes (p < 0.001). While most of the transplants with single-band OCT images (87%) had rosetted transplants, a considerable proportion of transplants having a multi-band OCT image were found to have well-laminated areas in the graft after histological evaluation. Following retinal transplantation in rodents, OCT imaging data correlated mostly with transplant morphology. OCT is a useful technique for in vivo screening and evaluation of retinal transplants. This technique determines surgical outcomes at a much earlier stage.

Structural and functional MRI reveals multiple retinal layers

“…Our assignment of MRI bands is supported by both general histologic assessment and correlations between histologic and MRI-derived laminar thicknesses. MRI-derived thicknesses of the neural retina, as reflected by the inner and middle bands, agree with histological measurements performed by us and others (19,20). In contrast, the outer band as measured by MRI was significantly thicker than the histological determination of the choroidal vascular layer.…”

The effects of cross-linked thermo-responsive PNIPAAm-based hydrogel injection on retinal function

“…There was no significant change in average retinal thickness (Fig. 3) in the region away from the hydrogel (p ¼ 0.5) and the average thickness of the retina remained in agreement with previous studies of normal rodent retinal thickness [19,33]. Though not significant, there was a small (w6%) decrease (p ¼ 0.4) in retinal thickness at week 1 post-injection followed by recovery to control values in the following weeks.…”

Layer-Specific Manganese-Enhanced MRI of the Retina in Light and Dark Adaptation

“…The study's neural retinal thickness is also in good agreement with the total thickness of the rat neural retina reported using histology, 27,28 ultrasound, 29 and optical coherence tomography. 30,31 In the outer retina, photoreceptors depolarize in dark and hyperpolarize in light. Depolarization is characterized by a net influx of positive ions, which triggers calcium influx into the intracellular space.…”