Hearing in C57BL/6J mice treated with sildenafil citrate.

C57BL/6J mice at 45 days after birth were treated with vehicle (N = 9) or sildenafil (N = 7). Hearing threshold value in each cell in column 3 represents average ABR threshold derived from 9 mice (N = 9) at that time point. ABR thresholds were recorded from the same group of mice over time, day 0, 7, 21 and 30 (also referred to as ‘longitudinal’ testing), to assess cumulative effects of sildenafil treatment on hearing. It should be noted that ‘day 0’ is pre-treatment or baseline ABR. The same explanation holds for column 4 (treated mice, N = 7). *A repeated measure ANOVA, non parametric, using a Friedman test was used to compare the hearing thresholds of the mice over time. A P value less than 0.05 is considered significant.