Inhibition of conjunctival scarring and contraction by a porous collagen-glycosaminoglycan implant

Abstract

Purpose: To study the healing processes of full-thickness wounds in the adult rabbit conjunctiva after grafting with a porous collagen-glycosaminoglycan (CG) copolymer matrix.

Methods: A 7-mm trephine was used to produce lesions of the bulbar conjunctiva down to the level of the bare sclera. Full-thickness removal of the conjunctiva and Tenon's capsule created a reproducible wound bed. Wounds either remained ungrafted (control) or were grafted with CG matrix. In previous studies, this CG matrix has induced partial regeneration of the dermis in the human, the swine, and the guinea pig. Healing of the conjunctival epithelium and underlying stroma was evaluated by histology, immunohistochemistry, and measurement of wound contraction kinetics.

Results: By 28 days, ungrafted wounds had closed by contraction (26.4% +/- 5.0% fornix shortening) and the formation of scarlike tissue comprising an aligned array of dense collagen populated with occasional fibroblasts. Grafting of identical defects with CG copolymer matrix resulted in inhibition of wound contraction (6.8% +/- 3.2% fornix shortening) and the formation of a tissue that resembled normal conjunctival stroma, being composed of a loose network of collagen fibers and fibroblasts. Contractile fibroblasts (myofibroblasts) were identified at the edge of both ungrafted and grafted wounds during the period of active contraction. Both ungrafted and grafted wounds were completely re-epithelialized by 28 days.

Conclusions: Implantation of CG copolymer matrix drastically reduced contraction and promoted the formation of a nearly normal subconjunctival stroma.