Tissue inhibitor of metalloproteinase‐1 messenger RNA expression is enhanced relative to interstitial collagenase messenger RNA in experimental liver injury and fibrosis

Liver fibrosis results from a relative imbalance between synthesis and degradation of matrix proteins. We have previously described release of the protein collagenase inhibitor, tissue inhibitor of metalloproteinase‐1 (TIMP‐1), by culture‐activated human hepatic stellate cells (HSCs). In this study, we have investigated the relative expression of TIMP‐1 and interstitial collagenase in culture‐activated rat HSCs and rat models of liver injury and fibrosis. The complementary DNA (cDNA) for rat TIMP‐1 was obtained by homology polymerase chain reaction (PCR) and sequenced. By Northern analysis using this probe, TIMP‐1 messenger RNA (mRNA) expression was up‐regulated with HSC activation by culture on plastic as defined by cellular expression of procollagen‐1. Interstitial collagenase mRNA was expressed in early 1. Interstitial collagenase mRNA was expressed in early culture (