New model of conjunctival scarring in the mouse eye

AIMS: To establish a simple model of conjunctival wound healing in the mouse eye. METHODS: 4 week old BABL/c mouse eyes were studied over a 14 day period. Surgical procedure under general anaesthesia involved a blunt dissection of the conjunctiva performed by injection of 25 microliters of PBS via a 27 gauge needle into one eye, while the contralateral eye was used as control. Mice were assessed clinically and sacrificed at 1, 2, 3, 7, and 14 days after surgery. Enucleated eyes were prepared for histological analysis. Development of scar tissue was studied with haematoxylin and eosin, oxidation aldehyde fuchsin, and van Gieson stains, with assessment of cellularity, extracellular matrix formation, and wound characterisation. RESULTS: Histological analysis revealed a marked and characteristic healing response initiated by a predominantly granulocytic inflammatory reaction at day 1 with peak fibroblast activity 3 days after surgery. Oxytalan fibres and newly laid collagen fibres were detected early in the subconjunctival wound area and up to 7 days after surgery. Remodelling and complete organisation of scar tissue was evident by day 14. CONCLUSION: A single subconjunctival injection in the mouse eye results in a marked and consistent healing response. This represents a simple, inexpensive, and reliable animal model of conjunctival scarring. The mouse is a biologically well characterised animal model and allows the use of a wide variety of molecular tools. There are potentially significant clinical applications, in particular in investigating the effects of modulating agents such as antimetabolites, growth factors, and their antagonists on conjunctival scarring.