Influence of radial keratotomy on endogenous hyaluronan in cornea and aqueous humour

Hyaluronan is known to appear in corneal wound tissue and is probably involved in the healing process. We measured the changes of endogenous hyaluronan in rabbit cornea and aqueous after radial keratotomy.

Corneal and aqueous hyaluronan concentrations were measured at different time intervals after radial keratotomies. Hyaluronan was extracted from corneal tissue with two methods employing either pronase or NaCl and measured with a radioimmunoassay. Histochemical staining for hyaluronan was done on the operated eyes.

Changes in corneal hyaluronan showed a similar time course with either extraction method. Maximal concentration was reached after 7 to 14 days with a return to normal values in 60 days. Aqueous hyaluronan and proteins were not significantly altered after surgery. Histochemical staining of the corneas demonstrated hyaluronan around the incisions along their entire extent. Blood vessels were absent in the wounds. An increase in elongated fibroblast-like cells was seen in the wound area.

Both quantitatively and histochemically, there is a pronounced increase of corneal hyaluronan in avascular, radial keratomy wounds in the rabbit. The findings suggest a role of hyaluronan in corneal wound healing.