Mice were treated with vehicle (Control), HN, HN-L12A, CP, CP+HN, CP+HN-L12A, or CP+HN+HN-L12A as described in experimental procedures (n=5 each group). Apoptotic cell numbers were determined by TUNEL staining method. HN or HN-L12A alone did not change apoptosis compared with control. Compared with control, CP increased germ cell apoptosis both in early+late (I–IV and XI–XII) and middle (VII–VIII) stages. CP+HN significantly suppressed CP-induced apoptosis in early + late stages but not in middle stages. CP+HN-L12A showed no preventive effect against CP-induced apoptosis in neither early+late or middle stages. CP+HN’s preventive effect was completely blocked by CP+HN+HN-L12A. Values are means ± SEM. Means with unlike superscripts are significantly (P<0.05) different.