Abstract: Objective To investigate the effects of silencing Smo gene on proliferation and apoptosis of rat primary chondrocyte in vitro. Method The primary chondrocyte was obtained by mechanical-enzyme digestion and identified by Immunohistochemical cells (ColⅡ). The experiment was divided into control group, control siRNA group and Smo siRNA 1~3 group. The siRNA were transfected into chondrocytes by lentivirus vector. After 72h, the cell viability was detected by MTT, Smo expressions were detected by RT-PCR and Western blot, and the apoptosis of chondrocyte was assessed by flow cytometry. Results All types of siRNA were transfected into primary chondrocyte by vectors, the Smo siRNA 1 ~ 3 could inhibit the expression of Smo mRNA and protein in chondrocytes, and Smo siRNA2 had the highest silencing rate (the expressions of Smo mRNA and protein were 0.19±0.03 and 0.39±0.07). The cell viability in Smo siRNA2 group was lowest (77.38%±7.19%), while the apoptosis rate of Smo siRNA2 was highest (21.43%±2.97%). Conclusion Silencing Smo gene in primary chondrocytes can inhibit proliferation and promote apoptosis, Smo may have a protecting role from apoptosis of the chondrocyte.

Key words: Primary chondrocytes, Lentiviral vector, siRNA, Hh signaling pathway , apoptosis, Proliferation