Figure 4

Effects of frequency of PW-LPL on intracellular ROS, mitochondrial activity, intracellular ATP of hDPSCs, changes in the nuclear transcriptional levels, and cell cycle cycles. LPL conditions were 1, 3, 30, 300, or 3000 Hz PW-LPL with same 30% duty cycle and 77 mJ/cm² total energy density, and NAC was for the case of 300 Hz PW-LPL. Cells were stained by the following dyes; (A) H2DCFDA, (B) MitoSOX, (C) JC1, and (D) ATP-luciferase. All the values were expressed as relative intensities to control. Intracellular ROS, mitochondrial membrane potential, and intracellular ATP increased, while mitochondrial superoxide decreased. hDPSCs were treated by PW-LPL of 1, 3, 30, and 300 Hz PW-LPL with 30% duty cycle daily for 3 days (n = 3 in all each experiment and 3 replicates). (E) mRNA transcriptional levels for SOD1, SOD2, BAX, and TGF-β1. There was no statistics (n = 3 in each experiment and 3 replicates). (F) The population ratio in each cell cycle was not changed significantly. Increase of intracellular ROS affects the transcription of redox contolling genes, however it did not induce apoptosis or cell cycle arrest. There was no statistics (n = 3 in each experiment and 3 replicates).