Expression of matrix metalloproteinases (MMP-2, MMP-3, and MMP-9) and fibronectin in lichen planus

BACKGROUND: Keratinocyte damage and lichenoid-interface reaction are the two major pathologic findings in lichen planus (LP). Matrix metalloproteinases (MMPs) are proteinases that participate in extracellular matrix (ECM) degradation and may play an important role in basal membrane (BM) damage in LP. Fibronectin (FN) mediates a variety of cellular interactions with ECM and plays important roles in cell adhesion, migration, growth and differentiation. OBJECTIVE: To determine MMP-2, MMP-3, MMP-9 and FN expressions in LP and discuss the possible associations. MATERIALS AND METHODS: Skin biopsy samples of 55 patients with LP and 11 normal skin were investigated. Five discoid lupus erythematosus (DLE) and 5 chronic dermatitis (CD) samples were also examined for comparison. Immunochemical stainings were performed for MMP-2, MMP-3, MMP-9 and fibronectin. RESULTS: Weak or absent expressions of MMP-2 and MMP-3 in epidermis; and dense MMP-9 expression in dermal inflammatory infiltrate cells were detected in LP. FN expression was lost in epidermal basal layer and papillary dermis. CONCLUSION: Loss of MMP-2, MMP-3 and FN in LP can be explained with the destruction of the epidermal basal layer. Similar expressions of MMP-2 and MMP-3 both in LP and DLE implied that these MMPs may be involved in the pathogenesis of interface dermatitis.