Abstract
Purpose: :
Topical application of a connexin43 specific antisense oligodeoxynucleotide (AsODN) following corneal wounding by photo–refractive keratectomy in an animal model reduces the inflammatory response and oedema and increases the rate of epithelial recovery. We demonstrate here the effect of the AsODNs on re–epithelialisation in an ex vivo human cornea model.
Methods: :
Three matched pairs of donor corneas were stored, suspended on culture sticks in New Zealand Eye Bank culture medium (MEM+2% fetal bovine serum, plus–L–Glut, PSN and antibiotics, Hepes buffered pH 7.53). Corneas were removed from the medium and treated by transepithelial, excimer laser, photo–therapeutic keratectomy (Technolas 217z). Ablations were 200 microns deep in a central 5.0mm diameter zone with a blend zone to 8.6mm. Corneas were then placed onto a Millipore culture insert to form an air–liquid interface organotypic culture, with culture medium raised to the level of the limbus. 100 microlitres of AsODN in 30% w/v Pluronic F–127 gel (BASF) at 2 micromolar final concentration was added directly onto the area of the ablation zone on one cornea; the control cornea in each pair was untreated. Corneas were cultured for 24 hours at 34oC then fixed in 4% paraformaldehyde for whole mount and histological analysis of epithelial recovery.
Results: :
The original area of ablation was calculated to be 58 mm2. The total area of epithelial regrowth 24 hours post ablation was 30.9 mm2 (SD 9.4) in the control corneae versus 42 mm2 (SD 8.7) for connexin43 specific AsODN treated corneae. AsODN treatment increased the rate of epithelial recovery in the human corneas (ex vivo) by 40% (SD) with 72% recovery within 24 hours (versus 53% in controls).
Conclusions: :
A single application of connexin43 specific AsODN significantly increases the rate of early corneal epithelial recovery following excimer laser ablation, providing potentially important clinical opportunities in relation to speed of epithelial healing and duration of post–surgical pain following photo–refractive keratectomy.
Keywords: refractive surgery: PRK • gap junctions/coupling • cornea: epithelium