Evaluation of plastic compressed collagen for conjunctival repair in a rabbit model.

Conjunctival repair is a crucial part of ocular surface reconstruction. Due to limitations of currently used substitute tissues, there is a need for the development of new scaffolds of consistent quality for conjunctival reconstruction. This study explored the biocompatibility and surgical usability of plastic compressed collagen (PCC) as an alternative conjunctival substitute. PCC gels were produced by polymerization of collagen type I followed by plastic compression. Conjunctival defects were trepanned in rabbits and grafted using PCC or human amniotic membrane (AM) or remained ungrafted. Number of sutures, defect size, conjunctival hyperemia and fornix depth were assessed at day 0, 3, 10, 14 and 28. Granulocytic infiltration, epithelialization, goblet cell count and collagen fiber alignment were examined histologically at day 10 or 28. Suture-loss, defect size, hyperemia and fornix depth of the PCC group were not significantly altered compared to AM. Histologically, granulocytic infiltration revealed mild inflammation at day 10 but did not differ between the PCC and AM group at day 10 or day 28. PCC was well integrated into the recipient conjunctiva with partial epithelialization after 10 days. After 28 days, all groups revealed a closed, multilayered epithelium with equal amount of goblet cells and randomly aligned stromal collagen fibers and no indication for conjunctival scarring. In summary, PCC gels offer a good surgical applicability and ocular surface biocompatibility with minor host reaction and no evidence of consecutive conjunctival scarring.