Fig. 2. Apoptotic oocytes and testicular germ cells in the male gonads. Sections were made at 23 (A,B), 25 (C,D) and 27 (E,F) days post-hatching, as the gonads changed from ovary-like tissue to testes, and mature testes were sectioned at 40 (G,H) and 70 (I,J) days post-hatching. Apoptotic cells were detected by TUNEL staining (B,D,F,H,J) and were counterstained with haematoxylin and eosin (A,C,E,G,I). Large numbers of TUNEL-positive oocytes (black and white arrowheads) were detected from 23 to 25 days post-hatching (A–D). Apoptotic spermatocytes (arrows) were detected at 40 days post-hatching (G,H). Large numbers of TUNEL-positive spermatogonia (yellow arrows), spermatocytes (black and white arrows) and spermatids (red arrows) were detected at 70 days post-hatching (I,J). TUNEL-positive somatic cells (red arrowhead) were detected in the ovarian cavity at 25 days post-hatching. An asterisk indicates the fragmented nucleus of an apoptotic oocyte. ed, early diplotene oocyte; oc, ovarian cavity; po, perinucleolar oocyte; sc, somatic cell; sg, spermatogonia; so, spermatocyte; sp, sperm. Scale bars, 20 µm.
