CELL-MIGRATION AND PROLIFERATION DURING THE IN-VITRO WOUND REPAIR OF THE RESPIRATORY EPITHELIUM

The respiratory epithelium is frequently injured by inhaled toxic agen ts or by micro-organisms. The epithelial wound repair represents a cru cial process by which surface respiratory cells maintain the epithelia l barrier integrity. The repair process involves both cell migration a nd proliferation, but as yet, the kinetic of these two mechanisms has not been extensively studied. Using an in vitro model of human respira tory epithelium wound repair, proliferative cell immunofluorescent sta ining and a computer-assisted technique allowing the tracking of livin g cells, we studied the cell proliferation and migration during the wo und repair process. Respiratory epithelial cells were dissociated from human nasal polyps and cultured on a collagen I matrix. At confluency , a chemical wound was made on the culture. We observed that the cell mitotic activity peaked at 48 h after wounding (23% of the cells) and mainly concerned the cells located 160 to 400 mu m from the wound edge . The migration speed was highest (35 to 45 mu m/h) for the spreading cells at the wound edge and progressively decreased for the cells more and more distant from the wound edge. The temporal analysis of the ce ll migration speed during the wound repair showed that it was almost c onstant during the first 3 days of the repair mechanism and thereafter dropped down until the wound closure was completed (after 4 days). We also observed that over a 1-hour period, the intra-individual and int erindividual Variation of the cell migration speed was 43% and 37%, re spectively. These results demonstrate that cell proliferation and cell migration during respiratory epithelial wound repair are differently expressed with regard to the cell location within the repairing area. (C) 1997 Wiley-Liss, Inc.