Activation of fibroblasts in collagen lattices by mast cell extract: A model of fibrosis

Background: Mast cells are resident connective tissue cells able to secrete numerous inflammatory mediators in response to tissue aggression and might be implicated in the fibrotic processes. Objectives: To study the effects of mast cell products on fibroblast activity in connective tissues. Methods: Mast cell extract was prepared by sonication of pure mast cell preparations obtained by peritoneal lavage of rats and added to the culture medium of fibroblast-populated collagen lattices. Results: Mast cell extract was able to decrease the contraction of the collagen lattices, to stimulate total protein and collagen synthesis, and to increase the expression and activation of gelatinase A/MMP-2. Conclusion: These data are consistent with the hypothesis that mast cells in connective tissue may be responsible for fibroblast activation at the early phases of tissue repair and fibrosis.