Fig. 3

Downregulation of OPG offset protective effect of ASC conditioned media. (a) OPG-siRNA-mediated downregulation of OPG in H₂O₂-treated ASCs. ASCs were transfected with 20 nM of OPG-specific siRNA for 24 hours, and then exposed to 100 μM of H₂O₂ for an additional 48 hours. mRNA expression of OPG normalized by 18 s rRNA expression. *p < 0.05, #p < 0.05 compared to H₂O₂-treated group. (b) Effect of OPG-specific siRNA on the OPG production from ASCs exposed to H₂O₂. OPG-siRNA (20 nM)-transfected ASCs were cultured in the presence of 100 μM of H₂O₂ for 48 hours, and the amount of OPG in ASC culture media was determined using an OPG-specific ELISA kit. *p < 0.05 compared to untreated control, #p < 0.05 compared to H₂O₂-treated group. (c) Viability of OPG-siRNA-transfected ASCs exposed to 100 μM of H₂O₂. *p < 0.05 compared to H₂O₂-treated group. (d) Effect of three different types of H₂O₂CMs on H₂O₂-induced cell death of H9c2 cells. *p < 0.05. H₂O₂CM ASC conditioned media prepared by culturing ASCs with 100 μM of H₂O₂ for 48 hours, H₂O₂CM/Reagent conditioned media obtained using transfection reagent-treated ASCs, H₂O₂CM/siRNA conditioned media obtained using OPG-specific siRNA-transfected ASCs, OPG osteoprotegerin