Stromelysin-1-deficient fibroblasts display impaired contraction in vitro

Targeted disruption of the stromelysin-1 gene in mice causes a delay in excisional wound healing due to a failure in wound contraction. Therefore, we postulated that stromelysin-1 activity is responsible for initiating contraction. To test this hypothesis, we compared the contractile capacity of fibroblasts from stromelysin-1 knockout mice (strom-1 KO) with that of normal fibroblasts using a collagen gel contraction model. Fibroblast cultures were established from explants of skin and lung parenchyma from strom-1 KO and wild-type mice, then transferred to the surface of collagen gels. The extent of contraction was determined by measuring greatest gel diameter. Results demonstrated that (1) all fibroblasts contracted collagen gels in a uniform concentric fashion, (2) skin fibroblasts from both sets of mice exhibited greater gel contraction than did lung fibroblasts, and (3) strom-1 KO fibroblasts demonstrated significantly less contraction (21-23%) than wild-type fibroblasts. These data support the hypothesis that absence of stromelysin-1 results in defective fibroblast contraction that may contribute to delayed wound healing.