Abstract
Purpose :
Evaluate the safety of a subretinal organoid/stem celltransplantation technique in rat eyes. Determine the efficiency of the technique as to maximize the integration and functionality of the transplanted cells.
Methods :
We chose the retinal degenerate RhoS334ter-3 rat model(immunodeficient and immunocompetent) because it replicates many features of human retinal degenerative diseases. Rats were anesthetized by i.p. injection of Ketamine/Xylazine(n=77). Surgical preparations were conducted under sterile conditions, including the application of povidone and atropine eye drops to left eye. To provide optimal exposure to the surgical field, two 6-0 sutures were used for upper eyelid retraction and two 8-0 sutures used on the superior conjunctiva. We performed conjunctival dissection with Vannas scissors and then disinserted the superior rectus muscle. A diamond knife was used to create 0.9 mm scleral incision between episcleral veins, exposing the subretinal space. Then 3 microliters of balanced salt solution were injected beneath the retina to create a bubble. Implants were prepared and injected into the subretinal space using a specialized injector(0.22 x 0.84 mm set at 1.5 mm) with a slow release of content. The injector was withdrawn slowly with gentle side-to-side movements to prevent displacement of the transplant. Sclera was closed with 10-0 sutures and the 8-0 conjunctival sutures were removed. The fundus was examined to confirm placement and position of the implant, assess the status of Optic Disc, and check for any potential bleeding. Then the 6-0 sutures were removed. Rats were examined 2-3 weeks post-surgery and then every 2 months by SD-OCT;( Bioptigen).
Results :
Intraoperative adverse effects included insufficient exposure, bleeding, implant displacement, corneal ulcer, and inadvertent intravitreal injection. Postoperatively, outcomes revealed choroidal damage(n=12), SHAM surgery effects(n=12), retinal folds(n=5), optic disc injury (n=8), corneal opacity(n=13), cataracts(n=2), vitreous hemorrhage(n=4), and one case of endophthalmitis.
Conclusions :
The intraoperative phase presented challenges that can interfere with the postoperative outcomes. These findings highlight the need for careful consideration of potential adverse effects and the importance of refining the technique to improve safety and efficacy in future applications.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.