Figure 3. Photoreceptor cell ratio in the central and peripheral retina 7 days after a single systemic administration of 60 mg/kg N-methyl-N-nitrosourea (MNU) to p53^−/−, p53^+/−, and p53^+/+ mice. Photoreceptor cell ratio was calculated as [(outer retinal thickness)/(total retinal thickness)]×100. In mice treated with MNU, regardless of their p53 status, the total retinal thickness and the outer retinal thickness of the central and peripheral retina were significantly decreased, resulting in a statistically significant decrease in the photoreceptor ratio of MNU-treated mice compared to vehicle-treated controls. Asterisk is p<0.01 and compared with vehicle controls.