Synergistic Effect of Ethanol and Mitomycin C in the Corneal Stroma

Abstract

Purpose:: To investigate the combined effects of ethanol and mitomycin C (MMC) applicatin on the corneal stroma of rabbits that had photorefractive keratectomy (PRK).

Methods:: PRK to correct -9 diopters of myopia was performed in 24 rabbits. Half of the rabbits had ethanol application before removing the epithelium and the other half had the epithelium manually removed without ethanol. Rabbits in both groups had topical MMC 0.02% applied for 12 seconds immediately after the excimer laser ablation. Rabbits were sacrificed at 4 hours and 4 weeks after surgery and immunohistochemistry was performed with TUNEL assay, α-smooth muscle actin (α-SMA) and DAPI.

Results:: More TUNEL-positive cells were observed in the ethanol-treated group compared to the mechanical debridement group at 4 hours after surgery (p < 0.02). No significant difference in α-SMA positive cells was detected between the two groups at 4 weeks after sugery. However, a decreased keratocytes density in the anterior stroma was more pronounced in the ethanol treated group compared to the mechanical debridment group (p < 0.03).

Conclusions:: Ethanol application for epithelial removal during PRK seems to produce a synergistic effect with MMC, resulting in fewer keratocytes (10.6% less) in the anterior stroma of rabbit corneas treated with MMC alone after PRK.

Keywords: apoptosis/cell death • cornea: clinical science • refractive surgery: PRK