Dynamic change of cells expressing MMP-2 mRNA and MT1-MMP mRNA in the recovery from liver fibrosis in the rat

Background/Aims: The aim of this study was to investigate whether both matr ix metalloproteinase-2 (MMP-2) and membrane type 1 MMP (MT1-MMP) participat e in the spontaneous resolution of liver fibrosis. Methods: Transcription of both genes was examined by reverse transcription- polymerase chain reaction (RT-PCR) and in situ hybridization (ISH). Gelatin ase activity was investigated by zymography. Results: Gene expression by RT-PCR showed that both genes increased in the process of liver fibrosis, then decreased gradually in the recovery phase. ISH revealed that distribution of positive cells changed quickly in the rec overy phase. Positive cells were widely seen in the liver, mainly around fi brous septa, in the aggressive phase, but were exclusively observed at the interface between the resolving fibrous band and the parenchyma, then were diffusely located in the lobules in the recovery phase. Main cells expressi ng both mRNAs seemed to be stellate cells for their morphology, though they did not express characteristic cell markers. Some hepatocytes and Kupffer cells expressed both mRNAs in the recovery phase. Gelatinase activity of MM P-2 increased in the recovery phase of 8-week-treated rat liver by gelatin zymography. Conclusions: The results of present study suggest that both enzymes partici pate in the destruction of extracellular matrix in coordination with MMP-13 . (C) 2001 European Association for the Study of the Liver. Published by El sevier Science B.V. All rights reserved.