Effect of immunosuppression on outcome measures in a model of rat limbal transplantation.
OBJECTIVE
To examine the effect of immunosuppression with intramuscularly injected cyclosporine and topical corticosteroid on limbal allograft survival in a new model in the inbred rat.


METHODS
Orthotopic limbal tissue harvested from male Fischer 344 (isografts) or male Wistar-Firth donors (allografts) was sutured into superior and inferior lamellar excision sites in female recipient Fischer 344 rats. Grafts were examined clinically for at least 55 days. Superficial epithelial cells were sampled weekly, and the DNA extracted and probed for the male-specific gene Sry by polymerase chain reaction. Recipients were killed at established intervals for immunohistochemistry. Graft-recipient animals were randomly assigned to receive either intramuscular cyclosporine plus topical prednisolone phosphate or vehicle for 4 weeks from the time of transplantation.


RESULTS
Isografts survived for a median of more than 55 days. Allografts underwent clinical rejection at a median of 6 to 7 days after grafting. Acutely rejecting allografts showed a dense mononuclear infiltrate consisting of activated CD4(+) and CD8(+) T cells with some macrophages. Genomic Sry was usually detectable in cells sampled from the ocular surface for more than 55 days in isografts, but not beyond 7 days in allografts. Immunosuppression prolonged allograft survival significantly, as assessed clinically, but did not prolong donor cell survival on the ocular surface, as assessed by detection of genomic Sry.


CONCLUSIONS
A robust model of limbal transplantation was developed in the rat. Isografts survived for the long term, whereas allografts underwent rapid rejection. Although clinical allograft survival was prolonged to a modest extent by immunosuppression, donor cell survival on the ocular surface was not improved.
Mills
Richard A D
RA
Department of Ophthalmology, Medical Centre, Flinders University of South Australia, Bedford Park 5042 SA, Australia. richard.mills@flinders.edu.au
Coster
Douglas J
DJ
Williams
Keryn A
KA
D000287:Administration, Topical; D000818:Animals; D017690:Cell Transplantation; D016572:Cyclosporine / Q000627:therapeutic use; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism / Q000637:transplantation*; D005260:Female; D006084:Graft Rejection / Q000188:drug therapy / Q000473:pathology; D006085:Graft Survival / Q000187:drug effects*; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007273:Injections, Intramuscular; D016850:Limbus Corneae / Q000166:cytology* / Q000601:surgery*; D008297:Male; D023421:Models, Animal; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011239:Prednisolone / Q000031:analogs & derivatives* / Q000627:therapeutic use; D051381:Rats; D011916:Rats, Inbred F344; D011920:Rats, Inbred WF; D051876:Sex-Determining Region Y Protein; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000378:metabolism; D014157:Transcription Factors; D014184:Transplantation, Homologous; D016896:Treatment Outcome
D004268:DNA-Binding Proteins; D007166:Immunosuppressive Agents; D009687:Nuclear Proteins; D051876:Sex-Determining Region Y Protein; C497747:Sry protein, rat; D014157:Transcription Factors; C009022:prednisolone phosphate; D016572:Cyclosporine; D011239:Prednisolone