Subretinal posterior pole injury induces selective proliferation of RPE cells in the periphery in in vivo studies in pigs.
OBJECTIVE
To study topographical differences in porcine retinal pigment epithelial (RPE) cell proliferation (1) in vivo, after experimental central surgical subretinal injury, and (2) in vitro.


METHODS
Domestic pigs underwent either experimental RPE debridement (n = 5), subretinal amniotic membrane transplantation (n= 4), or both (n= 1) in the left eye. RPE cell proliferation was assayed by injection of the thymidine analogue 5-bromodeoxyuridine (5-BrdU) at postoperative day 0 and 1. RPE cells in S-phase were identified by their incorporation of 5-BrdU, as detected by immunohistochemistry. The in vitro proliferation of primary RPE isolates from the peripheral and central retina was assayed by a colorimetric assay and by [(3)H]thymidine incorporation.


RESULTS
After subretinal surgery, in vivo incorporation of 5-BrdU was seen in peripheral RPE cells in 8 of 10 surgically treated eyes, but never in central RPE cells. This observation was true of both types of experimental surgery performed. In vitro, RPE isolates from the pre-equatorial region consistently yielded higher cell densities than did RPE cell isolates from more central parts of the epithelium. This was apparent through the three first passages of porcine RPE cells in culture. After 1 and 4 days in culture, pre-equatorial RPE cells had incorporated significantly more [(3)H]thymidine than had the more central RPE cells.


CONCLUSIONS
Experimental subretinal surgical injury of the RPE below the central retina is followed within 48 hours by a peripheral, but not a central, proliferation of RPE cells. In vitro, peripheral RPE cells have a higher proliferative capacity than do central RPE cells.
Kiilgaard
Jens F
JF
Eye Pathology Institute, University of Copenhagen, Denmark. jfiilgaard@dadlnet.dk
Prause
Jan U
JU
Prause
Michala
M
Scherfig
Erik
E
Nissen
Mogens H
MH
la Cour
Morten
M
D000650:Amnion / Q000637:transplantation; D000818:Animals; D001973:Bromodeoxyuridine; D002452:Cell Count; D049109:Cell Proliferation; D002478:Cells, Cultured; D004261:DNA Replication; D003646:Debridement; D015807:Eye Injuries, Penetrating / Q000150:complications*; D010857:Pigment Epithelium of Eye / Q000473:pathology*; D012160:Retina / Q000293:injuries*; D013552:Swine
D001973:Bromodeoxyuridine