COLOCALIZATION OF HYALURONAN AND WATER IN RABBIT CORNEAS AFTER PHOTOREFRACTIVE KERATECTOMY BY SPECIFIC STAINING FOR HYALURONAN AND BY QUANTITATIVE MICRORADIOGRAPHY

Purpose, Endogenous hyaluronan (HA) has previously been shown to be a part of corneal wound healing after photorefractive keratectomy (PRK). HA is known to bind considerable amounts of water. This study aimed t o show whether HA colocalized with water in the wound area after PRK. Methods, Five New Zealand White rabbits were subjected to PRK in one e ye each. After 4 weeks, the rabbits were killed and the corneas were f reeze-sectioned. The freeze-dried sections were exposed to soft x-rays generated at 3 kV and the microradiographs were evaluated densitometr ically. The same sections were then stained for the presence of HA usi ng the HA-binding region of bovine nasal cartilage proteoglycans linke d to biotin. Results, The microradiographs showed, in a zone underlyin g the epithelium, that the water content was increased. In the corresp onding zone, the cornea stained positive for HA. Conclusion, HA that i s reactively formed in the corneal wound after PRK colocalized to the hydrated area of the corresponding location as revealed by quantitativ e microradiography. The findings suggest that HA causes local shifts i n water content in the corneal wound and thereby also local shifts in transparency.