The role of gingival crevicular fluid and salivary interstitial collagenases in human periodontal diseases.

Interstitial collagenases (matrix metalloproteinase-1, EC 3.4.24.7), isolated from extracts of inflamed human gingiva, gingival crevicular fluid and saliva were characterized for their molecular weight, proteolytic and non-proteolytic activation and substrate specificity against soluble collagen types I, II and III. All three collagenases had Mr of 70 K. The enzymes existed predominantly in a latent form that could be activated by aminophenylmercuric acetate, gold thioglucose and hypochlorous acid. Among serine proteases tested, trypsin, chymotrypsin, neutrophil cathepsin G and a combination of trypsin and human gingival fibroblast prostromelysin activated gingival and salivary interstitial collagenases. Plasmin and plasma kallikrein, however, were relatively ineffective activators. The collagenases degraded soluble type I and II collagens at apparently equal rates but considerably faster than they did type III collagen. These findings suggest that the characteristics of interstitial collagenases found in inflamed human gingiva, gingival crevicular fluid and saliva are consistent with those of human neutrophil interstitial collagenase rather than the fibroblast-type interstitial collagenase. Thus, neutrophils are suggested to be the main source of such enzymes in inflamed human gingiva, crevicular fluid and saliva during adult periodontitis.