OBJECTIVETo investigate the effect of chemically synthetic small interfering RNA (siRNA) targeting connective tissue growth factor (CTGF) on the synthesis and secretion of extracellular matrix (ECM) in hepatic stellate cells (HSC).

METHODSChemically synthetic siRNA targeting CTGF was transfected into HSC T6 (an active HSC line in rats) by oligofectamine package, and untreated HSC T6 were used as control. Total RNA and protein of the cells, after their incubation with siRNA for 24, 48 and 72 hours, were extracted, and the supernatants were collected. The expressions of CTGF and type I and III collagen genes were detected by means of reverse transcription-polymerase chain reaction (RT-PCR) and/or Western blot. Contents of hyaluronic acid and type III pro-collagen in the supernatants were determined by radioimmunoassay.

RESULTSThe expression of CTGF at mRNA and protein level and type I and III collagen at mRNA levels were markedly down-regulated in siRNA-transfected HSCs. The contents of hyaluronic acid and type III pro-collagen in the supernatants decreased by 46%+/-7%, 52%+/-7%, 53%+/-7% and 29%+/-18%, 29%+/-7%, 27%+/-5%, compared with those of the blank control at 24, 48 and 72 hours.

CONCLUSIONSChemically synthetic anti-CTGF siRNA can significantly inhibit CTGF gene expression in HSC, and markedly reduce the synthesis and secretion of ECM including type I and III collagen and hyaluronic acid. The siRNA-directed suppression of CTGF gene in HSC was maintained for 72 hours. This suggests that chemically synthetic siRNA may be a potential in preventing and treating liver fibrosis and may have a promising future for development