Radiation-quality-dependent bystander cellular effects induced by heavy-ion microbeams through different pathways

Area of Science:

• Radiation Biology
• Heavy Ion Physics

Background:

• Bystander cellular effects, where cells not directly irradiated are affected, are crucial in understanding radiation responses.
• Heavy-ion microbeams offer precise irradiation for studying these complex cellular interactions.

Purpose of the Study:

• To investigate radiation-quality-dependent bystander cellular effects using heavy-ion microbeams.
• To explore the influence of different ion species (carbon, neon, argon) on cellular responses.

Main Methods:

• Utilized heavy-ion microbeams (carbon, neon, argon) with a 20 μm diameter at the Takasaki Ion Accelerators for Advanced Radiation Application.
• Assessed surviving fractions (SFs) and mutation frequencies (MFs) at 0.5, 3, and 24 hours post-irradiation.
• Investigated the role of gap-junctions, vitamin C, and dimethyl sulfoxide in modulating bystander effects.

Main Results:

• Carbon ions significantly reduced SFs without gap-junction inhibitors at early time points, with mutations observed.
• Argon ions showed delayed cell killing at 24 hours, suppressed by vitamin C.
• Bystander effects on mutation frequency were observed at 24 hours, independent of gap-junction inhibition.

Conclusions:

• Bystander cellular effects are dependent on biological endpoints, ion species, and time post-irradiation.
• Different ion species elicit distinct cellular responses, indicating varied underlying biological pathways.
• Gap-junctions, vitamin C, and other factors play differential roles in mediating these heavy-ion-induced bystander effects.