Expression of matrix metalloproteinases in the chronic subdural haematoma membrane.

To study the role of matrix metalloproteinases (MMP) in the development of chronic subdural haematoma, we investigated the expression and activity of MMPs (MMP-1, -2, -3, -7 and -9) and tissue inhibitors of MMP (TIMP-1 and -2) in capsules of chronic subdural haematoma from 10 patients. Outer membranes of chronic subdural haematoma were immunostained for MMP-1, MMP-2, MMP-9, TIMP-1 and TIMP-2. Moreover, we confirmed MMP activity in membranes by SDS-PAGE zymography and in situ zymography. These results suggest that MMP degrades extracellular matrix in outer membranes of chronic subdural haematoma, which is thought to decrease their integrity followed by direct haemorrhage and exudation of oedematous fluid from membrane vessels into the haematoma cavity.