Urokinase down-regulation by aprotinin in rabbit corneal cells after photorefractive keratectomy.

PURPOSE: To examine the effect of aprotinin eye drops on urokinase-type plasminogen activator (uPA) gene expression in rabbit corneal cells during wound healing after photorefractive keratectomy (PRK).

METHODS

Both eyes of 22 rabbits were subjected to PRK. One eye of each rabbit was treated with antibiotic eye drops five times while the contralateral eye was treated at the same time with antibiotic eye drops and a serine protease inhibitor. The animals were sacrificed at different time frames, and 2-4 rabbits were used for each time point. Half of each cornea was used for the determination of the amount of uPA mRNA after reverse transcription and real-time quantitative polymerase chain reaction, while frozen sections were prepared from the other halves for in situ zymography to detect uPA activity.

RESULTS

The level of uPA mRNA in corneal cells was markedly increased in corneal samples obtained hours after PRK. The time-dependent up-regulation of uPA mRNA was strongly dependent on the diameter of the area from which the epithelial cells were removed before the surgery. Independently of the time scale of uPA up-regulation, application of eye drops containing aprotinin significantly diminished the uPA expression. In situ zymography confirmed that aprotinin has also decreased overall uPA activity.

CONCLUSIONS

Aprotinin down-regulates uPA gene expression in corneal cells during the wound-healing phase after PRK.