Figure 7.
Transplantation of germ cells into recipient mice and analysis of recipient testes. Germ cell transplantation was carried out to evaluate the (bisphenol A) BPA-induced effect on the stemness properties of spermatogonial stem cells (SSCs). Donor germ cells collected from F1 postnatal day (PND) 120 offspring were stained with PKH26 (red fluorescence). (A) Images in the left panel show fluorescence expression of seminiferous tubules (STs) and merged image of STs inside the recipient testis (scale bar = 2 mm). The middle panel represents fluorescence and merged view of the colonization of donor germ cells inside the recipient ST. White arrows represent the places of colonization, scale bar = 200 µm. The right panel represents a cross-section of the fluorescence and merged views of the colonization of donor spermatogonia (red) on the basement membrane (white arrows) of the recipient ST (black arrow indicates sperm tails generated from donor SSCs; scale bar = 40 µm). (B) Bar graph represents the number of donor cell-derived colonies per 105 transplanted germ cells. Total numbers of mice/testes analyzed were 8/14, 8/15, 10/18, and 8/14 for control, no-observed-adverse-effect-level (NOAEL)-, lowest-observed-adverse-effect-level (LOAEL)-, and ethinylestradiol (EE)-exposed groups, respectively. Asterisk (*) indicates significant differences (* p < 0.05) compared to the control.