Dissection and cotransplantation of large pieces of RPE and neural retina; effect of protease K on the development.

. Purpose: This study attempts to cotransplant large pieces of the RPE and neural retina in the subretinal space of rabbits by using protease K for dissection of the donor tissue, and to investigate the effect of dissection technique on the development of the grafts. Methods: Eyes from 15-day-old pigmented rabbit embryos were partly digested by protease K to assist dissection of sclera and the choroid from RPE and neural retina. Large pieces of RPE and the neural retina thus obtained were cotransplanted into the eyes of adult albino rabbits who were allowed to survive for up to 63 days. The transplants were examined under light microscope. Results: It was possible to transplant large sheets of RPE and neural retina together. Both the RPE and the neural retina survived after cotransplantation. Retinal pigment epithelium survived in layers, but at places formed clusters. In cotransplants neural retina formed rosettes, developed gliosis, and photoreceptors failed to develop outer segments, possibly due to the action of protease K. Conclusion: Proteases seem to be injurious for the development of the neural retina.