Figure 2. γH2AX immunostaining counterstained with hematoxylin shows that γH2AX foci are almost undetectable in the subventricular zone (SVZ) (A) of the lateral ventricle, subgranular zone (SGZ) (B), rostral migratory stream (RMS) (C) and the border between dorsal hippocampus (O/A: border between stratum oriens and alveus) and corpus callosum (CC) (D) of P4 mice without irradiation. Irradiation with 5Gy induced obvious γH2AX foci (arrows) in SVZ (A’, A” is magnified from the ellipse in A’), SGZ (B’, B” is magnified from the ellipse in B’), RMS (C’, C” is magnified from the ellipse in C’) and the border between O/A and CC (D’, D” is magnified from the ellipse in D’). Furthermore, many apoptotic bodies (arrowheads) appear in SVZ (A’, A”), SGZ (B’, B”), RMS (C’, C”) and the border between O/A and CC (D’, D”) at 1 day after irradiation at P3. Scan bar=50μm in (A) applies to (B–D) (A’–D’) Scan bar=25μm in (A”) applies to (B”–D”).