Near-infrared exposure changes cellular responses to ionizing radiation

Area of Science:

• Biophysics
• Cell Biology
• Radiation Oncology

Background:

• Near infrared (NIR) and X-ray radiation impact cellular processes differently.
• NIR is generally considered beneficial, stimulating metabolism, while X-rays cause DNA damage and cell death.
• Mitochondrial metabolism, regulated by NIR, influences genomic stability post-X-irradiation.

Purpose of the Study:

• To investigate the impact of NIR exposure on cellular responses to X-radiation.
• To analyze how NIR affects genomic stability, reactive oxygen species (ROS), cell cycle progression, and DNA repair after X-ray exposure.

Main Methods:

• Fibroblasts, retinal progenitor cells, and keratinocytes were exposed to nonthermal NIR followed by clinically relevant X-ray doses.
• Assessed genomic instability, ROS levels, cell cycle entry into S-phase, and DNA double-strand break repair efficiency.

Main Results:

• Combined NIR and X-ray exposure led to increased genomic instability, evidenced by higher mitotic catastrophe ratios.
• Elevated levels of ROS and increased entry of X-irradiated cells into S-phase were observed.
• Impaired DNA double-strand break repair was a significant outcome of the combined radiation exposure.

Conclusions:

• Pre-exposure to NIR significantly alters cellular responses to X-rays.
• NIR may negatively impact the efficacy of radiotherapy by promoting genomic instability and hindering DNA repair.
• Further research is needed to understand the clinical implications for cancer treatment following NIR exposure.