Sperm concentration from cauda epididymis in control and ICI-treated mice. The left Y-axis applies to days 8–59, which were analyzed by the optical dissector method. The right Y-axis applies to day 125, which were counted using the Hamilton Thorne semen analyzer system (Beverly MA). The data are presented as means ± SEM. Significant differences (*) between control and ICI-treated means are noted (p < 0.05).