Lamelar keratoplasty in dogs using equine fetal membrane as graft: experimental study

Purpose: To evaluate the applicability of the equine fetal membrane (amniotic membrane, chorion and alantoid) as graft in lamelar keratoplasty in dogs. Methods: 9 mixed breed dogs were used, according to the ARVO statement for use of animals in ophthalmic and vision research. Superficial keratectomy was performed with a 5 mm trephine and a 6 mm diameter fragment of the fetal membrane that was sutured in place with 8-0 nylon simple interrupted stitches. Clinical examination were performed during 2, 7, 15 and 60 days and, afterwards, the animals were euthanized; the eyes were enucleated for histological study. Results: Clinically, one could observe slight corneal edema near the implant since the early phases, until the middle stage of the investigation. Neovascularization appeared progressively; its higher intensity was observed in the intermediate phase, disappearing gradually. At 60 days, one could notice a macula at the surgery site. The histological findings showed epithelialization and perfect integration of the graft to the receptor tissue at early stages; the cellular and vascular reactions were more intense in this phase. On day 15, the vascular elements were reduced in relation to the matrix and cellular elements. At any stage, inflammatory infiltrate in the graft, as well at the site of the suture were not observed. Conclusions: The equine fetal membrane (amniotic membrane, chorion and alantoid) can be useful as graft in lamellar keratoplasty in dogs.

Corneal transplantation; Fetal membranes; Animal; Dogs; Horses