Extracellular matrix (ECM) turnover is a widespread but in completely understood process. Many studies have been con ducted with the aim of discovering the general mechanisms which produce and maintain the ECM in tissues. Wound re pair in animals has always been a suitable "tool" for exploring these mechanisms. In such a pathologic event, the different components of the healing system can be readily observed since they are exaggerated. It has now become clear that the regulation of protease/inhibitor activity is one of the most im portant steps in maintaining the integrity of ECM in the...