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| Structure and Function of Embryonic Rat Retinal Sheet Transplants |
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| 作者：Qing Pen… 文章来源：Doheny Eye Institute(in USA), Dept.of Ophthalmology(PhD), Union Hospital, Tongji medical College, WuHan HuBei, 430022(in China) 点击数993 更新时间：2006/6/30 12:11:01 文章录入：彭清 责任编辑：毛进 |
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To determine by light and electron microscopy the characteristics of sheets of embryonic rat retina transplanted to the subretinal space of transgenic retinal degenerate S334ter-3 rats.
Methods
Seven transgenic S334ter-3 rhodopsin-mutant retinal degenerate rats received retinal sheet transplants in the subretinal space of one eye at postnatal day 31. The donor tissue was derived from transgenic rats expressing human placental alkaline phosphatase (hPAP) in all cells. Embryonic day 19 (E19) retina sheets were transplanted to the subretinal space of one eye with a custom-made implantation tool. At 2-3 months after surgery, visual responses were recorded in a visual center of the brain, the superior colliculus (SC), in 5 of the 7 rats. Transplanted eyes were processed for light microscopy (LM) and electron microscopy (EM). Vibratome-sectioned slices were cut 80mm thick and
processed for hPAP immunohistochemistry with DAB staining. Selected slices were embedded in epon. Semithin sections were stained with hematoxylin-eosin (H-E) or toluidine blue. Ultrathin sections were examined in a Zeiss EM10 microscope.
Results
All 5 transplants that were recorded in the brain showed responses to low light ranging between -3.42 to -2.8 log cd/m2 in a small area of the SC corresponding to the placement of the transplant in the host retina. Most of the transplants contained some well-laminated areas with correct polarity in the subretinal space. Rosettes of photoreceptors with inner and outer segments were found in larger areas. In laminated areas, the outer segments of photoreceptors faced the host retinal pigment epithelium (RPE). Immunohistochemistry for hPAP with Diaminobenzidine (DAB) staining (ABC method) indicated dark-brown, electron dense transplant staining and showed the obvious border to the host retina which showed a light-brown color. Electron microscopy sometimes showed a glial demarcation membrane between host and transplant, but penetration of transplant processes into the host retina could often be seen.
Conclusions
Sheets of E19 rat retina transplanted to the subretinal space of S334ter-3 rats develop for 3 months without immune rejection. Ultrastructurally, well-developed photoreceptors and many normal synapse types were seen within the transplants. The border between host and transplant could be clearly identified by hPAP immunohistochemistry. The restored
light sensitivity recorded in the brain of transplanted rats gives hope that retinal transplantation has the potential to help human patients with retinal diseases.
Supported by Foundation Fighting Blindness; Private Funds, Foundation for Retinal Research, Fletcher Jones Foundation, NIH EY03040.
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