Abstract: Objective Liver fibrosis is characterized by increased deposition and altered composition of extracellular matrix. The aim of this study was to construct recombinant vector carrying interstitial collagenase(MMP-13) and investigate if the expression of collagen I could be inhibited in rat hepatic stellate cell(HSC) overexpressing MMP-13 in vitro. Methods The plasmid expressing MMP-13(dl6-95-MMP-13) was constructed through inserting the full length of MMP-13 gene into the AAV vector dl6-95 which includes the ITR of AAV. Then, dl6-95-MMP-13 or dl6-95 plasmid was transfected into HSC for 7 days. The level of MMP-13 and collagen I mRNAs and proteins were analyzed by real time PCR and Western blotting. Results The plasmid expressing MMP-13(dl6-95-MMP-13) was constructed successfully. After dl6-95-MMP-13 plasmid was transfected into HSC for 7 days, real time PCR results showed that the level of MMP-13 mRNA increased significantly compared with HSC transfected with dl6-95 plasmid(without MMP-13), whereas the transcription of collagen I had only slight increase. Western blotting results showed that both the pro-MMP-13 and active MMP-13 increased significantly, especially the active form of MMP-13. After transfected with dl6-95-MMP-13, the expression of collagen I was inhibited significantly. Conclusion MMP-13 overexpression in HSC could inhibit the expression of collagen I significantly. This inhibition occurred mainly through degradation of collagen I protein, rather than through regulating the transcription of collagen I.

Key words: hepatic stellate cell, liver fibrosis, matrix metalloproteinase-13, collagen I