Suppression of IA formation in TNFR1-deficient mice. (A) Incidence of IAs in wild-type (WT), TNFR1-heterozygous (hetero), and TNFR1-deficient (KO) mice. IA was defined as a lesion with disrupted internal elastic lamina by Elastica van Gieson staining. The number of mice used for each genotype is shown in parentheses. *indicates p < 0.05. (B) Systemic blood pressure in each genotype (WT, wild-type mouse; Het, TNFR1-heterozygous mouse; KO, TNFR1-deficient mouse) after aneurysm induction. Systemic blood pressure (SBP, systolic blood pressure; MBP, mean blood pressure) was measured by the tail-cuff method. All bars indicate the mean ± SEM.