An immunoassay for qualitative estimation of collagenase activity in mammalian tissues

Collagen, the most abundant protein of the mammalian body, is specifically degraded by collagenase. Collagenase activity and subsequent collagen degradation are the main aspects of essential biological processes such as bone remodeling, tissue repair and wound healing. Measurement of collagenase activity is of interest to a wide variety of investigations using mammalian tissues, including clinical specimens. Most assays for collagenase activity are based on chemical modification of the substrate collagen. A unique feature of the present method is that it allows the rapid, qualitative measurement of collagenase activity without the requirement of substrate modification. It is based upon both substrate digestion by collagenase and reaction of undigested collagen with its antibody. Collagenase activity is measured by quantitation of immunoreactivity of undigested collagen using an enzyme-linked immunosorbent assay (ELISA). The assay is performed in 96-well microtiter plates used for ELISA. The advantages of this method are several: (a) a highly specific reaction between substrate collagen and its antibody that rules out the possibility of nonspecific quantitation; (b) the use of a nonmodified substrate; (c) the ease and rapidity of performance of a microassay. Application of the microassay to mammalian tissue homogenates was demonstrated in rat uterus tissue and ventricular myocardium of normal and hypertensive rats.