Abstract
Purpose: :
Amniotic membrane (AM) transplantation is used to reconstruct the ocular surface. Lack of standardization and limited transparency are some disadvantages of this graft material. Keratin films (KF) have been proposed as a transparent carrier, suitable for corneal epithelial cell expansion and ocular surface reconstruction. We report the results of the first in vivo application in a rabbit model
Methods: :
In accordance with ARVO Statement for the Use of Animals in Ophthalmic and Vision Research, 29 New Zealand white rabbits underwent 4mm superficial keratectomy with dissection of a peripheral stromal pocket in the right eye. 6 rabbits were used as a control (C), 6 received AM and 17 a 5mm KF implant which was fixed without sutures by insertion into the circumferential stromal pocket. A soft contact lens and third lid tarsorrhaphy were used to secure the implant. Postoperatively all animals received dexamethasone 0.1% eye drops daily; 14 of them (6 KF, 4 AM, 4 C) were sacrificed after 10 days, the remaining 15 (11 KF, 2 AM, 2 C) after 4 weeks
Results: :
Slit lamp examination performed at the end of follow-up showed a central corneal scar in all eyes receiving a KF, in 4 of 6 eyes receiving AM and in 4 of 6 control eyes. This was particularly prominent in eyes 4 weeks after KF implantation. Neovascularisation was present in the superior corneal quadrants in 14 of 17 eyes with KF, in 2 of 6 eyes with AM however not in controls. Histological examination showed complete epithelial healing in C and AM group after 10 days. The KF group showed strong inflammatory stromal infiltrates with predominantly eosinophilic granulocytes surrounding the film on which epithelial cells grew. After four weeks the KF group showed a severe prominent, stromal scar reaction while in the C and AM group, the epithelium healed, even if the latter showed mild inflammatory response and scar reaction
Conclusions: :
In this preliminary study KF does not seem to support epithelialisation and wound healing. The presence of a strong inflammation in eyes receiving KF, suggests that an immunologic reaction may have been triggered to compounds of the KF and hence further modifications of the implant are required
Keywords: wound healing • cornea: epithelium