Differential expression of alternatively spliced fibronectin in normal and wounded rat corneal stroma versus epithelium.

Purpose: The polymerase chain reaction was used to examine fibronectin (FN) expression during corneal scrape wounding with specific attention to the presence, absence, or gross changes of alternatively spliced FN as differentially expressed in the corneal stroma versus the epithelium in normal and wounded tissue.

Methods: Specific FN cDNA sequences were synthesized from rat cornea with total RNA and were amplified using various sets of synthetic oligonucleotide primers.

Results: The authors observed the presence and sustained the expression of total FN, EIIIA, EIIIB, and V-region FN mRNA in normal and injured corneal stroma for up to 3 weeks after scrape wounding. In contrast, complementary overlying epithelial samples were virtually devoid of FN message.

Conclusions: These data suggest that functionally different, alternatively spliced FN isoforms may be involved both in the maintenance of the normal cornea and in wound healing, and that their synthesis occurs in situ principally by the stroma rather than by the epithelium.