Abstract: Objective：To clone the recombinant plasmids expressing connective tissue growth factor(CTGF) short hairpin RNA(shRNA) by Pgenesil1 plasmid, and to screen the highly efficient shRNA. Methods：Three pairs of two DNA sequences containing small hairpin structure and one pair of unspecific control sequence were designed and synthesized respectively. The complement forms were obtained by annealing and inserted into plasmid Pgenesil1 with U6 promoter, and the recombinant plasmids were transformed into DH5α strain. Finally the plasmids identified by restriction enzyme were used for sequence analysis. Four pairs of recombinant plasmids being transfected into HSCT6,the expression of CTGF mRNA level was determined by reverse transcriptionpolymerase chain reaction 24 hours later. Results: The CTGF shRNAs were successfully inserted into plasmid Pgenesil1. The recombinants were identified by endonuclease digestion and sequencing. Compared with the controls, the expression of CTGF mRNA level in HSCT6 transfected with CTGF shRNA recombinants was markedly downregulated by (74±5)%(P<0.01) and (61±3)%(P<0.05) respectively in two groups of recombinant plasmids, wherease it had not any significant changes in another shRNA and unspecific shRNAtransfected and only with transfection reagent to HSCT6. Conclusion: Three pairs of recombinants expreessing CTGF shRNA are successfully constructed, shRNA sequences potently inhibiting CTGF are screened out successfully too, which lends itself to new gene therapy for liver fibrosis.

Key words: Connective tissue growth factor, RNA interference, Short hairpin RNA, Plasmids, Liver fibrosis, Gene expression