Figure 2.

Effect of quercetin on cellular sensitivity to IR.

Notes: Cells were pretreated with or without quercetin (100 μM) for 12 h, followed by X-irradiation. (A) The cellular sensitivity to IR was assessed by clonogenic survival assay. (B) Cells were either sham irradiated or exposed to 4 Gy IR 1 h after pretreatment with vehicle or 100 μM quercetin. DNA damage was seen in the form of a comet tail under a fluorescence microscope (left) and it was quantified (right). For each comet image, PI intensities of the head and tail portions were obtained, and the percentage intensity of the tail portion was multiplied by the size of the tail (DNA migration) to yield a tail moment. *p<0.05, when compared with control. (C) Cells were treated with 4 Gy of irradiation (in the presence or absence of quercetin) and harvested at 12 h. Immunofluorescence microscopy was conducted using anti γ-H2AX or Rad51 staining. Shown are mean foci per nucleus counted from three independent experiments. *p<0.05, when compared with control.

Abbreviations: DAPI, dihydrochloride; IR, ionizing radiation; PI, propidium iodide; Qu, quercetin.