Figure 6. In Townes SCD mice, increased oxidative stress is associated with changes in caspase activity.

Box plots of respective variables indicate the variable’s median and first and third quartiles and the whiskers the 5^th and 95^th percentiles. Given the evidence of increased oxidative stress in hippocampi and cerebral cortex in Townes mice, we tested the hypothesis that there would be alteration in caspase-3 activity. In hippocampi, caspase-3 activity in Townes mice varied according to mouse age and genotype (p<0.001 for genotype by age interaction). A. In hippocampi, among young mice, homozygous (p<0.001) and heterozygous (p<0.001) Townes had significantly lower caspase-3 activity compared to controls. B. Conversely, among old mice, homozygous (p=0.046) and heterozygous (p=0.041) Townes had significantly higher caspase-3 activity compared to controls. As animals aged (A and B), in controls, there were decreases (p=0.003), whereas in heterozygotes (p<0.001) and homozygotes (p=0.002) there were increases in caspase-3 activity levels and these patterns of changes were significantly different (p<0.001 for genotype by age interaction). In cerebral cortex (C and D), we also observed that there were genotype by age interaction (p=0.005). Specifically, as animals aged, in controls, there were decreases (p=0.008), whereas in heterozygotes (p=0.049) increases, and in homozygotes (p=0.409) no changes in caspase-3 activity levels in cerebral cortex and these patterns of change comparing young and old animals were significantly different (p=0.005). N=4-6 mice per genotype and age group