Effects of Red Light Emitting Diode on Apoptosis of HeLa Cells and Suppression of Implanted HeLa Cells Growth in Mice

Abstract

Low intensity irradiation of cells by laser was an effective method of biostimulation. Here, we have extended these actions to evaluate the apoptosis effects in red light emitting diode (RLED) exposure. Through morphological observation, flow cytometric analysis, intracellular calcium measurement and RT-PCR, we found that HeLa cells in 24 h RLED irradiation in in-vitro experiments would significantly affects the induction of cellular apoptosis, and morphological changes such as the loose arrangement of cells, the noticeable development of apoptotic bodies,and the accompaniment of arrested S phase and activated caspases-3,-6,-8. Moreover, intracellular calcium concentrations markedly increased 40.3 ± 1.3% and 43.1 ± 0.8% respectively, relative to an extracellular solution containing the Ca²⁺ and Ca²⁺ free unexposed group. In in-vivo tests, RLED irradiation decreased the growth of tumors on day 50 and attenuated the elevation of vascular endothelial growth factor (VEGF) expression in HeLa cell implanted BALB/c mice. Taken together, our results suggest that RLED could induce HeLa cell apoptosis and convey potential antitumor properties.