OBJECTIVETo test the hypothesis that the introduction of antisense transforming growth factor beta receptor I (TBRI) plasmid and antisense tissue inhibitor of matrix metalloproteinase (TIMP-1) eukaryotic expressing plasmid into a rat liver fibrosis model may influence the progression of liver fibrosis.

METHODSFragments of TBRI cDNA and TIMP-1 cDNA were obtained by reverse transcription polymerase chain reaction (RT-PCR) and then amplified by nest PCR. pcDNA3.1(+)-antisense TBRI eukaryotic expressing plasmid was constructed by directional and inverted joins with the purified linear pcDNA3.1(+) and the purified fragment of TBRI, as well as, pcDNA3.1(+)-antisense TIMP-1 eukaryotic expressing plasmid. The recombinant was identified by restriction endonuclease digestion and DNA sequence analysis. The recombinant plasmids were encapsulated with Lipofectmine 2000, and then they were injected intraperitoneally into the liver fibrosis model rats. The protein expression of type I collagen was evaluated by immunohistochemistry. VG staining of liver slides of the rats was used for histopathological examination.

RESULTSCompared with the empty plasmid control group and the disease control group, the deposition of type I collagen decreased in the three antisense treatment groups: antisense TBRI group (4.37+/-1.30) x 10(5), P less than 0.05; antisense TIMP-1 group (3.40+/-0.91) x 10(5), probability value less than 0.05; antisense TBRI + antisense TIMP-1 group (0.90+/-0.32) x 10(5), P less than 0.01; treatment control group (6.90+/-1.61) x 10(5); disease control group (7.34+/-1.68) x 10(5); and the normal control group (0.41+/-0.21) x 10(5)]. Significant differences in the pathological grades of fibrosis were found between the normal control group and the other five groups (P less than 0.05) and also between the disease control group and the three antisense treatment groups (antisense TBRI group P less than 0.05; antisense TIMP-1 group P less than 0.05; antisense TBRI + antisense TIMP-1 group P less than 0.01), but no difference was found between the empty plasmid control group and disease control group (P more than 0.05).

CONCLUSIONBoth antisense TBRI eukaryotic expressing plasmid and antisense TIMP-1 eukaryotic expressing plasmid can inhibit the progress of liver fibrosis. A combined action can inhibit the progress of liver fibrosis more.