Increased expression of gelatinases and alteration of basement membrane in rat soleus muscle following femoral artery ligation

Acute severe muscle ischaemia is characterized by significant remodelling of basement membranes of myofibres. It was hypothesized that peripheral artery insufficiency is accompanied by similar muscle extracellular matrix (ECM) changes involving matrix metalloproteinase gelatinases. Using a model of femoral artery ligation, both gelatinase activity and basement membrane component degradation were studied in hindlimb skeletal muscles. SDS-PAGE zymography of muscle homogenates showed that acute moderate ischaemia was followed by a significant transient increase in expression of 72- and 92-kDa gelatinases during 48 h; the latter probably originated from inflammatory cells. In situ zymography showed that this increase occurred chiefly at the periphery of myofibres. Immunolocalization demonstrated 72-kDa gelatinase in interspaces and at the periphery of myofibres, and suggested that this enzyme may explain the gelatinolytic activities found by in situ zymography. Type IV collagen and laminin staining showed that the gelatinase expression increase correlated with dramatic basement membrane component alterations. Our data show that even moderate ischaemia results in significant muscle basement membrane remodelling due to matrix degrading enzymes matrix metalloproteinases (MMP) gelatinases.