Fig. 1.

Representative photomicrographs of macaque ovarian tissue and follicles not exposed or exposed to neutral red (NR). NR diffuses through the plasma membrane and concentrates in viable follicles making possible to distinguish follicles in a pieces of tissue (a–c); white arrowheads depict follicles stained with NR in situ. (d) Isolated secondary follicles without NR staining from the no-stained tissue group (controls). (e) Secondary follicle (non-viable) that did not stain with NR isolated from ovarian tissue exposed to NR. (f) Isolated secondary follicle (viable) stained with NR. Isolated secondary follicles from tissue stained with NR (g). Scale bar = 200 μm (a), 100 μm (b, d–g), 50 μm (c)