ENZYMATIC ELUCIDATION OF THE RELATIONSHIP BETWEEN COLLAGEN AND ELASTIN: AN ELECTRON-MICROSCOPIC STUDY BY

Any information on the reaction of the fibrous connective tissue components to various reagents, particularly enzymes, is of interest in the fields of both health and disease. Until some understanding of the normal interrelationships of these structures is reached, no firm attempt to explain pathological findings can be made. Although it is dangerous to extrapolate test-tube results in explanation of changes found in vivo, most of the agents and con-ditions used in the present study are not too far removed from possible conditions in living mammals. Elastase and hyaluronidase are manufactured in man and recently collagenase activity has been demon-strated in canine pancreatic juice (Ziffren and Hosie, 1955). The mildly alkaline solutions employed could represent a pH value reached in pathological tissue, and most of the experiments were conducted at body temperature. Although previous work (Keech, Reed, and Wood, 1956) demonstrated that "moth-eaten " fibres (MEF) were intermediate structures midway between collagen and elastin, the present study shows without doubt that a further range of agents (physical, chemical, enzymatic) can cause breakdown of these structures to "elastin". Concurrent experiments on elastin are described, and objections raised to the use of the standard elastin substrate for electron micro-scopic work