Effect of 660nm visible red light on cell proliferation and viability in diabetic models in vitro under stressed conditions.

Abstract

The current study evaluated the photobiomodulatory effect of visible red light on cell proliferation and viability in various fibroblast diabetic models in vitro, namely, unstressed normal (N) and stressed normal wounded (NW), diabetic wounded (DW), hypoxic wounded (HW) and diabetic hypoxic wounded (DHW). Cells were irradiated at a wavelength of 660nm with a fluence of 5J/cm2 (11.23mW/cm2), which related to an irradiation time of 7min and 25s. Control cells were not irradiated (0J/cm2). Cells were incubated for 48h and cellular proliferation was determined by measuring 5-bromo-2'-deoxyuridine (BrdU) in the S-phase (flow cytometry), while viability was assessed by the Trypan blue exclusion test and Apoptox-glo triplex assay. In comparison with the respective controls, PBM increased viability in N- (P ≤ 0.001), HW- (P ≤ 0.01) and DHW-cells (P ≤ 0.05). HW-cells showed a significant progression in the S-phase (P ≤ 0.05). Also, there was a decrease in the G2M phase in HW- and DHW-cells (P ≤ 0.05 and P ≤ 0.05, respectively). This study concludes that hypoxic wounded and diabetic hypoxic wounded models responded positively to PBM, and PBM does not damage stressed cells but has a stimulatory effect on cell viability and proliferation to promote repair and wound healing. This suggests that the more stressed the cells are the better they responded to photobiomodulation (PBM).