To explore the effects of red LEDs on the proliferation and osteogenic differentiation of human stem cells from apical papilla (hSCAPs).

hSCAPs were obtained by isolation, culture and flow cytometry in vitro and irradiated with 1, 3, 5, and 7 J/cm² red LEDs. The proliferation of hSCAPs was detected using a CCK-8 assay. The osteogenic differentiation of hSCAPs was evaluated using alkaline phosphatase (ALP) staining, ALP activity assay and Alizarin red quantitative detection. The effect of 5 J/cm² red LEDs on the expression levels of the ALP, Runx2, OCN, OPN and BSP genes and proteins was detected by RT-PCR and western blot, respectively.

Red LEDs at 1, 3, 5, and 7 J/cm² promoted the proliferation of hSCAPs (P < 0.05). The effects of red LEDs with different light energies on the proliferation of hSCAPs were different at different time points (P < 0.05). On the 7th and 14th days after irradiation, red LEDs promoted the osteogenic differentiation of hSCAPs, and the effect of 5 J/cm² red LEDs was the most obvious under osteogenic induction culture conditions (P < 0.05). Red LEDs (5 J/cm²) promoted the expression of the ALP, Runx2, OCN, OPN and BSP genes and proteins (P < 0.05).

Red LEDs promoted the proliferation and osteogenic differentiation of hSCAPs.