Structure and function of embryonic rat retinal sheet transplants.
OBJECTIVE
To evaluate retinal sheet transplants in S334ter-line-3 retinal degenerate rats by comparing visual responses recorded electrophysiologically with morphology based on light and electron microscopy.


METHODS
S334ter-line-3 retinal degenerate rats (n = 7) received retinal sheet transplants between postnatal days 28 and 31. The donor tissue was derived from transgenic embryonic day 19 (E19) rat retinae expressing human placental alkaline phosphatase (hPAP). Fresh retinal sheets were gently transplanted into the subretinal space of the left eye with the help of a custom-made implantation tool. Selected rats (n = 5) were subjected to electrophysiologic evaluation of visual responses from the superior colliculus about 84-121 days after surgery. Transplanted eyes were processed for light microscopy (LM) and electron microscopy (EM) evaluations.


RESULTS
All the transplanted rats that were evaluated for visual responses in the brain showed responses to very low light stimulation (-3.42 to -2.8 log cd/m(2)) of the eye in a small area of the superior colliculus corresponding with the placement of the transplant in the host retina. Histologic evaluation showed that most of the transplants contained well-laminated areas with correct polarity in the subretinal space. Inside the transplant areas, rosettes of photoreceptors with inner and outer segments were found. In the laminated areas, the outer segments of photoreceptors were facing the host retinal pigment epithelium (RPE). Immunohistochemical evaluation of hPAP donor cells revealed areas with specific staining of the transplants in the subretinal space. Electron microscopic evaluation showed a glial demarcation membrane between the host and the transplant, however, processes originating from the transplant were observed inside the host retina.


CONCLUSIONS
Sheets of E19 rat retina transplanted into the subretinal space of S334ter-line-3 rats survived without immune rejection and continued to show visual function when tested after 3 months. Well-developed photoreceptors and many synapse types were seen within the transplants. hPAP staining showed a certain degree of integration between the host retina and the transplant suggesting that transplanted photoreceptors contributed to the restored light sensitivity.
Peng
Qing
Q
Department of Ophthalmology, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China.
Thomas
Biju B
BB
Aramant
Robert B
RB
Chen
Zhenhai
Z
Sadda
Srinivas R
SR
Seiler
Magdalene J
MJ
D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D004594:Electrophysiology; D016332:Fetal Tissue Transplantation; D006085:Graft Survival; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D010775:Photic Stimulation; D020419:Photoreceptor Cells, Vertebrate / Q000648:ultrastructure; D010920:Placenta / Q000378:metabolism; D051381:Rats; D011922:Rats, Mutant Strains; D012160:Retina / Q000196:embryology* / Q000378:metabolism / Q000601:surgery / Q000648:ultrastructure; D012162:Retinal Degeneration / Q000503:physiopathology / Q000601:surgery*; D012374:Rod Cell Outer Segment / Q000648:ultrastructure; D013477:Superior Colliculi / Q000503:physiopathology; D014019:Tissue Donors; D019737:Transplants; D014796:Visual Perception
D000469:Alkaline Phosphatase