Evaluation of the Effect of Near Infra-red Photobiomodulation on Buccal Fat Pad-Derived Stem Cells

Background: Laser photobiomodulation can be a useful adjunctive method in tissue engineering in enhancement of proliferation and differentiation of mesenchymal stem cells. Buccal fat pad-derived stem cells (BFPSCs)has been introduced as a promising source for craniofacial bone tissue engineering. Current study aimed to evaluate the effects of near infra-red photobiomodulation on (BFPSCs)behavior. Methods: After cell isolation from a surgically excised sample of human buccal fat pad, third passage cells were irradiated twice daily for three consecutive days. Irradiation was performed with 6 different laser settings by two modes of continuous and pulsed (50% duty cycle) and energy densities of 3 and 6 J/cm2 and two different output powers (0.1W and 0.3W) using a 940nm laser. Anon-irradiated group served as control. The test was repeated in three different daysand every time cell viability was evaluated by MTT assay at intervals of 24, 48 and 72h. Based on viability results a setting was chosen for evaluation of osteogenic differentiation by Alizarin red staining. Results: The highest proliferation was observed at irradiation of 3J, 0.3W, pulsed at 24h and 48h, however, after 72h the highest proliferation rate was related to 6J ,0.1W, pulsed. Considering the effect of 3J 0.3W pulsed modeon cell proliferation at an earlier time, this setting was used for osteogenic differentiation assay. Both microscopic and quantitative analysis of Alizarin Red staining showed that cells subjected to the 3J 0.3W Pulsed irradiation also resulted in an increase in mineralization of BFPSCs cultured in osteogenic induction medium compared to the negative control (p<0.05). Conclusion: According to the results of this study a pulsed mode of irradiations showed better viability results. Although the 3J/ cm2 0.3W, Pulsed irradiation showed significantly better results for viability and proliferation, however no statistically significant effect was observed in osteogenic differentiation.