[Expression of matrix metalloproteinases and tissue inhibitor of metalloproteinase by myofibroblasts--morphological study on corneal wound healing].

The matrix metalloproteinases (MMPs) and the tissue inhibitor of metalloproteinases (TIMPs) regulate the extracellular matrix and are important in the process of connective tissue remodeling. In this study, we investigated the expression of MMPs and TIMP-2 by myofibroblasts (MF) originating from keratocytes during the healing of alkali-burned and lacerated rabbit corneas. In light and/or electron microscopic immunohistochemistry, the MMP-1, 2, 9 and TIMP-2 antibodies reacted with MF in both types of corneal wounds. The clear expression of MMP-1 and the relatively faint immunoreaction of MMP-2 were observed in both types of healing from one week after wounding, while MMP-9 appeared from 3 weeks after injury. In addition, the levels of MMP-2 and 9 were increased from 4 weeks after alkali-burned injury. The clear expression of TIMP-2 was observed from 1 week after both types of wounds. These findings indicate that MF is deeply involved in degrading some of the key matrix proteins (such as type I collagen), and may play an important role in tissue remodeling in corneal wounds through production of MMPs and TIMP.