Fig. 3.

MMP-2−/− mice do not have decreased levels of active type I collagenase after chronic liver injury. Gelatin zymography performed on whole liver extracts from MMP-2+/+ and MMP-2−/− mice after 6 weeks of CCl₄ administration confirmed lack of MMP-2 activity in MMP-2−/− livers but presence in MMP-2+/+ livers (a). Active type I collagenase was measured using 5 and 10 µg samples of whole liver protein extract from MMP-2+/+ and MMP-2−/− mice after 6 weeks of CCl₄ administration (n = 4) by mixing samples with biotinylated bovine collagen. The resultant biotinylated fragments were then transferred into biotin-binding wells and detected using a streptavidin-enzyme complex and a microplate reader. Purified MMP-1 was used to generate standard curves. MMP-2−/− mice did not have significantly decreased amounts of hepatic type I collagenase activity as compared with MMP-2+/+ mice (b). Analysis performed in triplicate for each sample. Data represent means ± SEM