ALTERNATIVELY SPLICED FIBRONECTIN MOLECULES IN THE WOUNDED CORNEA - ANALYSIS BY PCR

Purpose. To determine whether certain fibronectin isoforms participate in corneal epithelial wound healing, the authors used the polymerase chain reaction to detect different splicing patterns of the EIIIA segm ent of fibronectin mRNA in epithelial scrape-wounded cornea of rats. M ethods. Specific fibronectin cDNA sequences synthesized from rat corne a with total RNA were amplified with various sets of synthetic oligonu cleotidc primers. Results. The authors detected both the EIIIA+ and EI IIA- fibronectin mRNA isoforms during corneal wound healing. The kinet ics of corneal expression of both total fibronectin mRNA and the EIIIA - fibronectin mRNA isoform was polyphasic; an initial decrease was fol lowed by an increase at 45 minutes, a second increase at 2 hours, and a third increase at 4 days after wounding. EIIIA+ fibronectin mRNA, no t found in normal cornea, also was detected during healing. Conclusion s. The expression of total fibronectin mRNA and both the EIIIA+ and EI IIA- fibronectin mRNA is upregulated during corneal epithelial wound h ealing. The expression of EIIIA+ fibronectin mRNA during wound healing , a fibronectin isoform that was highly expressed in embryonic tissue, suggests that this fibronectin isoform is involved functionally in co rneal wound healing.