Immunolocalization and gene expression of matrilysin during corneal wound healing

To investigate the protein level of matrilysin and stromelysin-1 and the gene expression of matrilysin in rat corneas after excimer keratectomy using immunofluorescence staining, reverse transcriptase-polymerase Chain Reaction (RT-PCR), and in situ hybridization.

Rat corneas were treated with 3-mm excimer laser keratectomy (193-nm ArF). Unwounded corneas served as controls. Confocal microscopy was used to immunolocalize matrilysin protein at 6 hours, 1 day, 3 days, 1 week, 4 weeks, and 8 weeks after surgery. RT-PCR was performed to analyze matrilysin mRNA in unwounded controls and in 3-day wounded corneas. In situ hybridization was performed to localize matrilysin mRNA.

Matrilysin was immunolocalized to the epithelial layers of unwounded and wounded corneas, predominantly to the leading edge at 6 hours and 1 day after wounding and to the epithelial layer at 3 to 7 days after surgery. Stromelysin-1 was expressed in the deep stromal layer in the first 3 days after wounding and in the area of newly synthesized stromal matrix 1 week after surgery. Upregulation of matrilysin expression 3 days after wounding was confirmed by RT-PCR. In situ hybridization revealed that the gene expression of matrilysin in rat corneas was upregulated during the migration phase (6 hours, 1 day) and that matrilysin mRNA was predominantly localized to the basal cell layers during the subsequent cell proliferation phase (7 and 14 days).

Basal epithelial cells express matrilysin during the migration proliferation phase of corneal wound healing after excimer keratectomy.