[The effect of corneal epithelial cells on the collagen gel contraction by keratocytes]

To understand the mechanism of corneal stromal wound contraction, we investigated the effect of corneal epithelial cells on the collagen gel contraction by keratocytes. Subcultured rabbit keratocytes embedded in type I collagen gel were cultured. Rabbit corneal epithelial cells were also cultured and the cultured medium was collected and used as an epithelial cell conditioned medium (ECCM). The collagen gel contraction by keratocytes was estimated by measuring the diameter of the collagen disc once a day for 5 days. The diameter of the collagen gel decreased in proportion to the number of keratocytes in the presence of fetal calf serum (FCS), but it decreased in inverse proportion to the concentration of collagen. The collagen gel contraction by keratocytes was enhanced by the addition of ECCM in a dose dependent manner. This stimulatory activity was found in ECCM obtained from 3 to 7 day cultivation of corneal epithelial cells. These findings demonstrated that keratocytes contracted collagen gel in the presence of FCS. It also appeared that corneal epithelial cells secrete a factor or factors that stimulate the collagen gel contraction by keratocytes.