Effects Of A Plasmid Expressing Antisense Tissue Inhibitor Of Metal Loproteinase-1 On Liver Fibrosis In Rats

Background No efficient therapy for liver fibrosis has been available. This study was aimed to provide evidence that the introduction of a plasmid expressing antisense tissue inhibitor of metalloproteinase-1 (TIMP-1 into a rat model of immunologically induced liver fibrosis can result in the increased activity of interstitial collagenase, thus enhancing the degradation of collagen.Methods Real-time nested polymerase chain reaction ( RT-Nested-PCR) and gene recombination techniques were used to construct a rat antisense TIMP-I recombinant plasmid that can be expressed in eukaryotic cells. Both the recombinant plasmid and an empty vector (peDNA3) were encapsulated with glycosyl-poly-L-lysine and injected into rats suffering from pig serum-induced liver fibrosis. The expression of exogenous transfected plasmid was assessed by Northern blot, RT-PCR, and Western blot. Hepatic interstitial collagenase activity was detected using fluorescinisothiocyanate ( FITC)-labeled type I collagen. In addition to hepatic hydroxyproline content, hepatic collagen types I and M were detected by immunohistochemical staining, and the stages of liver fibrosis by Van Gieson staining.Results Exogenous antisense TIMP-1 was successfully expressed in vivo and could block the gene and protein expression of TIMP-1. Active and latent hepatic interstitial collagenase activities were elevated ( P < 0.01), hepatic hydroxyproline content and the accumulation of collagen types I and M were lowered, and liver fibrosis was alleviated in the antisense TIMP-1 group ( P < 0.01) as compared with the model group.Conclusion The results demonstrate that antisense TIMP-I recombinant plasmids have some inhibitory effect on liver fibrosis.