Effect of TSA on hPDLSCs apoptosis. A. hPDLSCs were treated with 10% FBS, indicated concentration of TSA for 48 hrs after serum starvation for 24 hrs, and cell apoptosis was determined by a nuclear fragmentation assay. Data were presented as mean ± SD. *, P < 0.05 (ANOVA with Tukey’s post hoc test). B. hPDLSCs were treated with 10% FBS, indicated concentration of TSA for 48 hrs after serum starvation for 24 hrs, and cell apoptosis was determined by flow cytometry using annexin V-FITC and propidium iodide (PI) staining. C. hPDLSCs were treated with 10% FBS, indicated concentration of TSA for 48 hrs after serum starvation for 24 hrs. Cleaved-PARP and cleaved-caspase 3 were determined by western blotting.