The process of closure of experimental retinal holes in rabbit eyes.
BACKGROUND
To investigate the healing process of retinal holes, including the identification of the cell types which play an important role in the process, we created experimental retinal holes with minimal damage to retinal pigment epithelium (RPE) in rabbit eyes.


METHODS
Pars plana vitrectomy was performed in the rabbit eye. A dome-shaped retinal detachment (bleb; diameter 1.5 mm) was made by injecting balanced salt solution into the subretinal space, followed by making a retinal hole (diameter 0.5 mm) in the center of the bleb with a silicone-tipped extrusion needle. In one group of rabbits, fluid-air exchange was performed and sulfur hexafluoride gas was injected into the vitreous cavity postoperatively. In another group, gas tamponade was not performed. The operated eyes were examined ophthalmoscopically and enucleated at 1, 4, 7, 14, 30, and 90 days after surgery. Tissues were prepared in 5-microm sections for hematoxylin-eosin staining and immunohistochemistry with antibodies to cytokeratin 18 and glial fibrillary acidic protein (GFAP) and examined by light microscopy.


RESULTS
In the gas-injected eyes, the retinal holes were ophthalmoscopically closed by 7 days after the surgery. Microscopic examination revealed that the sensory retina around the retinal hole was reattached, and the area of retinal defect was covered with cells which were positive for cytokeratin 18 and GFAP by 7 days after the surgery. In the eyes without gas tamponade, the retinal holes did not close during the observation period.


CONCLUSIONS
These findings suggest that early attachment between the sensory retina and RPE could be essential for closure of a retinal hole, where glial and RPE cells might play an important role. This model seems to be useful to investigate the process of closure of retinal holes.
Yamana
T
T
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaramachi, Sakyo-ku, Kyoto 606-8507, Japan.
Kita
M
M
Ozaki
S
S
Negi
A
A
Honda
Y
Y
D000818:Animals; D015415:Biomarkers; D002455:Cell Division; D004195:Disease Models, Animal; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000473:pathology; D011817:Rabbits; D012160:Retina / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D012167:Retinal Perforations / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D013459:Sulfur Hexafluoride / Q000627:therapeutic use; D014945:Wound Healing
D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D007633:Keratins; D013459:Sulfur Hexafluoride