Ultraviolet light-emitting diode irradiation induces reactive oxygen species production and mitochondrial membrane potential reduction in HL-60 cells

Abstract

Objective Ultraviolet light-emitting diode (UV LED) irradiation at 280 nm has been confirmed to induce apoptosis in cultured HL-60 cells, but the underlying mechanisms remain unclear. This study aimed to investigate the effects of 280 nm UV LED irradiation on reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) in HL-60 cells. Methods HL-60 cells were irradiated with 0, 8, 15, or 30 J/m2 of 280 nm UV LED and incubated for 2 hours. The intracellular ROS levels were assessed using the fluorescent probe 2ʹ-7ʹ-dichlorodihydrofluorescein diacetate (DCFH-DA) and a fluorescence plate reader. MMP was determined by flow cytometry using 5,5ʹ,6,6ʹ-tetrachloro-1,1ʹ,3,3ʹ-tetraethylbenzimidazol-carbocyanine iodide (JC-1) staining. The apoptosis-related proteins Bax and Bcl-2 were evaluated by western blot. Results UV LED irradiation at 280 nm induced a dose-dependent increase in ROS production and loss of MMP, and it activated apoptosis at irradiation doses of 8 to 30 J/m2. These results were consistent with a previous apoptosis study from the authors’ group. Conclusion Enhanced ROS production and mitochondrial depolarization are two distinct but interacting events, and both are involved in UV LED-induced apoptosis in HL-60 cells.

Ultraviolet Radiation Promoted Hypoxia-Induced Apoptosis in HL-60 Human Promyelocytic Leukemia Cell Line

“…Our previous study confirmed that LED UV irradiation can inhibit the proliferation of HL-60 cells and induce cell apoptosis and necrosis [ 10 ]. UV LED can induce cell cycle arrest in the G0/G1 phase in HL-60 cells [ 18 ]. However, the effect of 280 nm LED UV irradiation on HL-60 cells under the hypoxic condition of the bone marrow hematopoietic microenvironment remains to be elucidated.…”

ARM-Based Indoor RGB-LED Visible Light Communication System

“…where N DATA indicates the length of the DATA field information, N CP indicates the number of useful subcarriers, N window indicates the number of window cover points, N FCH indicates the number of frame control header symbols, N FFT indicates the number of fast Fourier transform points, N pre indicates the number of leading symbols, and f s indicates the sampling frequency. e results from equation (11) show that the frame length of the system is significantly reduced. Combined with the OFDM symbol power spectrogram after windowing, the planned over-zero zone signal transmission is accomplished, thus effectively improving the energy efficiency of data communication.…”

“…LED-based VLC can greatly broaden the communication spectrum range and is one of the feasible solutions to alleviate the tight wireless spectrum resources. Its advantages are mainly re ected in these aspects [11][12][13]: (1) the data transmission speed is almost the same as that of optical ber.…”