FIGURE 6 from Uncovering the Protective Neurologic Mechanisms of Hypofractionated FLASH Radiotherapy

<p>FLASH irradiation protected against prolonged inflammation found in CONV mice, 6 months after irradiation. Representative images of reactive microglia CD68 (red) and DAPI (blue) in the male mouse hippocampus (<b>A</b>) and representative images of IBA1 (green), TLR4 (red), and DAPI (blue; Scale bar = 100 μm; <b>B</b>). <b>C,</b> Quantification of CD68 immunofluorescence in the hippocampus and medial prefrontal cortex. Male (left) and female (right) mice exposed to FLASH-RT exhibit no significant change in CD68 expression while CONV mice expressed a neuroinflammatory response. <b>D,</b> Quantification of IBA1 and TLR4 colocalization in the hippocampus and medial prefrontal cortex. Male and female mice exhibited decreased levels of the neuroinflammatory mediator TLR4 when compared with CONV irradiation. <b>E,</b> Inflammatory cytokines measured using ELISA. IL1α exhibited elevated expression after CONV-RT exposure when compared with controls while FLASH induced no changes. No significant changes were observed in TNFα or IL1β. All data were analyzed using a one-way ANOVA followed by Bonferroni multiple comparison test (<i>n</i> = 4/sex/treatment, two sections analyzed/region/animal). *, <i>P</i> ≤ 0.05; **, <i>P</i> ≤ 0.01; ****, <i>P</i> ≤ 0.0001.</p>