Figure 4. Adipogenic differentiation of HDPCs isolated by three different methods. Oil Red O staining of HDPCs-OG (a - d), HDPCs-ED (e - h), and HDPCs-Combined (i - l) cultures at 14 and 28 days after the induction of differentiation. Accumulated lipid droplets in HDPCs-OG (d), HDPCs-ED (h), and HDPCs-Combined (l) at 28 days after induction. Scale bar: 50 µm. HDPCs, human dental pulp cells; HDPCs-OG, HDPCs were isolated by the outgrowth method; HDPCs-ED, HDPCs were isolated by the enzymatic digestion method (collagenase/dispase/trypsin); HDPCs-Combined, HDPCs were isolated by the combination of both methods. ^*Asterisk indicates difference significant between control and treated groups (α = 0.05).