Inhibition of connective tissue growth factor expression decreases the expression of type 1 collagen and alkaline phosphatase mRNA in human osteoblastic MG 63 cells

Objective To investigate the inhibition effect of small interfering RNA(siRNA) on the expression of connective tissue growth factor(CTGF), and to observe the effects of down-regulation of CTGF on the expression of type 1 collagen and alkaline phosphatase mRNA in human osteoblastic MG 63 cells. Methods Three pairs of 21-nucleotide CTGF siRNAs directed to human CTGF mRNA 440,875and 910 targets were differently transfected into human osteoblastic MG 63 cells with DMRIE-C reagent package. Untreated and transfected scramble siRNA served as the blank control and nonspecific siRNA control respectively. Total RNA and protein of the cells after 48h incubation were extracted. The expression of CTGF in mRNA and protein level were assessed by northern blot and western blot, and the expression of type 1 collagen and alkaline phosphatase mRNA in human osteoblastic MG 63 cells were evaluated by semiquantitive RT-PCR, cell viability was tested by MTT assay. Results Compared with blank control group, the expression of CTGF mRNA and protein were markedly down-regulated by siRNA directed to 440 and 910 target of human CTGF mRNA, siRNA directed to 875 target and scramble siRNAs show no effect on the expression of CTGF. The expression of type 1 collagen and alkaline phosphatase mRNA was reduced in human osteoblastic MG 63 cells transfected with siRNAs directed to 440 and 910 targets, and cell viability significantly decreased in human osteoblastic MG 63 cells transfected with siRNAs directed to 440 and 910 targets. Conclusions CTGF siRNA can effectively reduced the expression of CTGF mRNA and protein. Inhibition of CTGF expression decreases the expression of type 1 collagen and alkaline phosphatase mRNA as well as cell viability in human osteoblastic MG 63 cells.