[Localization of extracellular matrix proteins after holmium YAG laser radiation in rat cornea].

PURPOSE: To understand corneal responses to holmium YAG (Ho: YAG) laser radiation, we used immunofluorescent microscopy to examine changes in the localization of extracellular matrix proteins.

METHODS

Rats were radiated with an Ho: YAG laser. On days 1, 3, and 7 after radiation, the eyes were enucleated and frozen. The cryosections were stained by immunofluorescent microscopy using antibodies against type I collagen, fibronectin, type IV collagen, and laminin.

RESULTS

One day after Ho: YAG laser radiation, contraction of the stromal collagen fibrils was observed. Keratocytes could not be observed at the radiated stromal region on day 1 after radiation. One week after radiation, keratocytes returned to the radiated area. Although the stromal collagen fibrils were contracted, they were stained by an antibody against type I collagen. Dense fluorescence for fibronectin was observed at the margin of the stromal acellular zone. Both laminin and type IV collagen were observed at the basement membrane under the corneal epithelium regardless of whether the corneas were radiated or not.

CONCLUSIONS

These results suggest that Ho: YAG laser radiation might be useful for collagen contraction of the stroma, without causing serious damage to the corneal epithelium or the basement membrane.