Figure 2.

Immunohistological features of human fetal testis explants after culture. (A) AMH expression. In tissue sections from a ten GW human testis explant, Sertoli cells were immunostained with anti-AMH antibodies (brown cytoplasm). Gonocytes are identified as white cells inside the seminiferous cords. Bar: 10 μM. (B) Double immunofluorescence for AMH and M2A (9.5 GW human testis explants). M2A staining (green) is exclusively localized in gonocytes, characterized as large seminiferous cells that do not express AMH, a marker of Sertoli cells (red). Scale bar: 10 μM. (C) Cytochrome P450 scc expression. (9 GW human testis explant). Leydig cells are identified by cytochrome P450 scc expression. They are localized in the interstitial tissue between the seminiferous cords, which are here delineated by a dotted line. Scale bar: 20 μM. (D) Double immunostaining for AMH and Ki67 (7.5 GW human testis explant). Sertoli cells are identified by AMH expression (brown) and cycling cells are Ki67-positive (purple). Black arrow: Ki67-negative gonocyte. White arrow: Ki67-positive gonocyte. White arrowhead: Ki67-negative Sertoli cell. Black arrowhead: Ki67-positive Sertoli cell. Scale bar: 10 μM. (E) Double immunostaining for AMH and BrdU (10.7 GW human testis explant). BrdU was added 2 h before the end of the culture. Sertoli cells are identified by AMH expression (purple) and cycling cells in S phase are detected by immunostaining for BrdU (brown). Black arrow: BrdU-negative gonocyte. White arrow: BrdU-positive gonocyte. Scale bar: 10 μM. (F) Double immunostaining for AMH and TUNEL (11.5 GW human testis explant). Sertoli cells are identified by AMH expression (brown cytoplasm) and gonocytes as cells with white cytoplasm inside the seminiferous cords. Apoptotic cell are identified by TUNEL assay (brown nucleus). Black arrow: TUNEL-negative gonocyte. White arrow: TUNEL-positive gonocyte. Scale bar: 10 μM. (G) Double immunostaining for AMH and cleaved caspase 3 (ten GW human testis explant). Sertoli cells are identified by AMH expression (purple cytoplasm) and gonocytes as cells with white cytoplasm inside the seminiferous cords. Apoptotic cell are identified by immunostaining for cleaved caspase 3 (brown nucleus). Black arrow: caspase 3-negative gonocyte. White arrow: caspase 3-positive gonocyte. Scale bar: 10 μM.