Effects of transforming growth factor-beta 2, interleukin 6 and fibronectin on corneal epithelial wound healing

Purpose. The aim of this study was to compare the effects of topically applied transforming growth factor-beta 2 (TGF-beta 2) and interleukin 6 (IL-6), alone and combined with fibronectin, on the rate of corneal wound healing in rabbits. Methods. Twenty-eight rabbits were used for the experiment. After the right eye of each rabbit was debrided with n-heptyl alcohol, the animals were divided into four treatment groups (six rabbits per group) and one control group (four rabbits). The debrided eyes were treated, beginning immediately after wounding and continuing every 2 hours from 8 a.m. to 8 p.m. for 48 hours. Group 1 received TGF-beta 2; group 2 IL-6; group 3, TFR-beta 2 and purified fibronectin; group 4, IL-6 and fibronectin; control group, balanced salt solution. At set intervals each eye was stained with fluorescein and photographed; epithelial defects were measured with a computer-assisted digitizer. The healing rate was calculated by linear regression analysis. Results. The mean healing rates in groups 1, 2, 3, 4, and controls were respectively 1.65 +/- 0.16, 1.68 +/- 0.11, 1.99 +/- 0.12, 2.23 +/- 0.09, and 0.93 +/- 0.18 mm(2)/h. Mean epithelial healing rates for all drug-treatment groups were significantly faster than controls. The healing rates of groups 3 and 4 were significantly faster than groups 1 and 2. Conclusions. We conclude that cytokines, in combination with extracellular matrix proteins, facilitate corneal epithelial wound healing in vivo, possibly by making corneal epithelial cells more sensitive to fibronectin receptors.