Figure 2. Xrcc1 deficiency increase SSB accumulation and exacerbates heart failure.

(a) Macroscopic and echocardiographic images of Sham- or TAC-operated Xrcc1^f/f and Xrcc1^αMHC-Cre mice. Scale bar, 2 mm. (b) TAC surgery was performed to Xrcc1^f/f and Xrcc1^αMHC-Cre mice and cardiac function after the operation was assessed by echocardiogram. LVDd, LV end-diastolic dimension; LVDs, LV end-systolic dimension; LVPWd, LV posterior wall dimension; LVFS, LV fractional shortening (Xrcc1^f/f mice: n=80, 22, 30, 11, 10; Xrcc1^αMHC-Cre mice: n=85, 28, 40, 13, 9 at each time point, respectively). Statistical significance was determined by Student's t-test at each time point. ^#P<0.05; ^##P<0.01 versus Xrcc1^f/f mice. (c) Heart, lung, and body weight of Sham- or TAC-operated Xrcc1^f/f and Xrcc1^αMHC-Cre mice were weighed 8 weeks after the TAC surgery (n=8, 9, 12, 7, respectively). Statistical significance was determined by one-way analysis of variance followed by the Tukey–Kramer HSD test. *P<0.05; **P<0.01 between arbitrary two groups. (d) Survival curve of Xrcc1^f/f and Xrcc1^αMHC-Cre mice after the TAC surgery (n=26, 33, respectively). Statistical significance was determined by Wilcoxon test. ^#P<0.05 versus Xrcc1^f/f mice. (e) The type of DNA damage in cardiomyocytes of Sham- or TAC-operated Xrcc1^f/f and Xrcc1^αMHC-Cre mice was assessed by comet assay (Alkaline comet: n=50, 64, 60, 67; Neutral comet: n=31, 57, 42, 50, respectively). Statistical significance was determined by Steel–Dwass test. **P<0.01 between arbitrary two groups. Column and error bars show mean and s.e.m., respectively.