Abstract
Purpose::
To evaluate the effect of topical administration of mitomycin-C (MMC), in the corneal wound healing in hens after photorefractive keratectomy (PRK).
Methods::
Right eyes of 64 adult Lothmann brown hens under PRK surgery were used. 32 eyes were topical treated with Mitomycin-C 0.02% for 2 minutes and 32 were untreated. Left eyes were used as a control.Clinical course was made under surgical microscopy, time of epithelial closure with fluorescein stain, haze by the Fantes method and pachymetry were evaluated. At different time points the eyes were exenterated and fixed for histopathological analysis with Hematoxilin-eosine and Masson Trichromic stains. Cell death was measured by TUNEL techniques, cell proliferation and differentiation were evaluated by immunofluorescence assays, and nuclei were stained with DAPI.Software ImajeJ for MAC-OX, and ANOVA analysis were used.
Results::
The time of epithelial closure was higher in the MMC treated (72 ѱ12 hours), than untreated eyes (48ѱ12 hours) (p<0.05). The increase in the grade of haze was higher in the untreated (1.5-2) than treated eyes (0.5-1) (p<0.05), in addition the treated corneas did not experiment an important increase in the pachymetry values while untreated corneas a high increase was observed (p<0.05). 6, 12 and 24 hours after surgery, the number of stromal positive TUNEL cells in the treated group was higher than untreated group although differences did not appear as clinically significant. The number of stromal proliferative cells was higher in the untreated group 2, 5 and 7 days after surgery and the imageJ picture analysis demonstrated an important increase in the surface (pixels) of alpha-SMA in the untreated than treated sections, 15 and 30 days after surgery (p<0,05), at these time points this analysis showed a high increase in the total stromal nuclei in the untreated than MMC treated corneas p<005 at the day 15 and not significant at the day 30. Masson tricromic stain demonstrated an important increase in the new collagen matrix in the untreated than MMC treated corneas.
Conclusions::
The antimitotic effect of Mitomycin-C was evident in the corneal wound healing process after PRK in hens. Although the MMC treated animals presented better clinical results, it could be compromised by our previous experiments in which MMC was detectable in the aqueous humour of the hen eye after topical application in PRK-treated and in intact epithelium eyes. The presence of MMC is of concern as it may lead to ocular toxicity in the long term.
Keywords: antibiotics/antifungals/antiparasitics • refractive surgery • wound healing