ABSTRACT
Objective Tissue inhibitor of metalloproteinase-1 (TIMP-1) is a multifunctional protein that has thc capacity to modify cellular activities and to modulate matrix turnover. This paper revealed the contributive role of TIMP-1 in progressive muscular dystrophy (PMD). Methods We examined the expression and cellular localization of TIMP-1 protein using biopsied frozen muscle from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), congenital muscular dystrophy (CMD) by immunohistochemistry, double immunofluorescence and Western blot analysis. Results The results of immunohistochemistry and double immunofluorescence showed that TIMP-1 was positive only in vascular endothelial cells of normal muscles. Immunohistochemistry and Western blot analysis showed that the staining intensity was distinctly increased in some dystrophic muscles of PMD for TIMP-1. Double immunofluorescence revealed that TIMP-1 strongly expressed in the regenerating muscle fibers, macrophages and macrophage infiltrating necrotic fibers. Some activated fibroblasts in endomysium and perimysium of DMD and CMD muscles were also positive for TIMP1. Conclusion The functional consequence of overexpression of TIMP-1 in the dystrophic muscles is unknown, but the elevated local expression of TIMP-1 in diseased muscles of PMD and their distinct distribution pattern provide evidence that TIMP-1 may participate in the pathogenesis of PMD.