Figure 6. RGCL neuroprotection is not due to effects of high dose cranial irradiation alone.

A: Representative photographs of control mice (no Tx) and mice that received head only irradiation (HO-XRT) demonstrate effects of irradiation on coat color and confirm radiation exposure in HO-XRT mice (top). Representative photomicrographs of NeuN⁺ neurons (red) in RGCL stained with NeuN antibody and visualized with Cy3-conjugated secondary antibody show a mild reduction in neuron density 8 months after HO-XRT (bottom). Scale bar  = 50 μm. B: Quantification of neuron density depicted as a percent of age-matched, non-irradiated wt controls demonstrates there is a mild reduction in RGCL neurons as a result of high dose irradiation without BMT in wt and APPswe-PS1ΔE9 mice, thus eliminating the possibility that high dose cranial irradiation underlies the neuroprotective effects of BMT.