IN-VITRO MODEL FOR CORNEAL WOUND-HEALING - ORGAN-CULTURED HUMAN CORNEAS

Healing of linear, non-perforating thermal burns was studied in 56 hum an corneas in an air/liquid organ culture system in serum free medium or in media supplemented with 10% fetal bovine serum, 10% human serum or 10% human plasma. The extent of epithelial wound healing was determ ined by measuring epithelial growth into the wound using digitized com puter scanning of light micrographs of 1 mu m sections. The cross-sect ional area of this epithelial growth entering the wound was significan tly greater for corneas incubated with either human serum (16,350 +/- 12,088 mu m(2)/day; p < 0.0001) or human plasma (20,571 +/- 12,276 mu m(2)/day; p = 0.0004) than for those incubated in serum free (1,784 +/ - 1,957 mu m(2)/ day) medium. There was no significant difference betw een epithelial growth in the serum free and fetal bovine serum supplem ented (3,779 +/- 2,580 mu m(2)/day) media or between that in human ser um and human plasma supplemented media. The thickness of the epitheliu m adjacent to the wound was greater in corneas cultured in fetal bovin e serum supplemented media than in corneas cultured in the presence of human serum. Similarly, the build-up of epithelium at the wound edge for corneas in either serum free or fetal bovine serum supplemented me dia was significantly greater than for either human serum or human pla sma supplemented media. The percentage of basal epithelial nuclei whic h incorporated bromodeoxyuridine (BrdU) increased during the first thr ee days of culture when it reached a plateau. Comparison of paired wou nded and unwounded corneas showed that wounding stimulated an increase in DNA synthesis. The extent of labelling was similar after seven day s for both serum free medium and human serum supplemented medium, indi cating that a serum-factor was not necessary for this stimulation. Imm unohistochemical (IHC) analysis showed that fibronectin was present ar ound the wound edges, in the stroma and along the basement membrane of the epithelium, after seven days of culture in either serum free or h uman serum containing media. Type IV collagen was found in the basemen t membrane of both groups but appeared along the wound edge and surrou nding the epithelial cell influx into the wound in human serum culture d corneas only. This cultured human cornea system offers a useful mode l for examining factors which modulate the course of wound healing.