Fig. 2.
Expansion of SSCs in serum-free medium supplemented with GDNF, soluble GFRα1, and bFGF. (A) MACS Thy-1 cells from C57 × ROSA were cultured in the conditions indicated. Fresh MACS Thy-1 cells and cultured cells were transplanted into recipient testes. The number of donor-derived spermatogenic colonies per 105 MACS Thy-1 cells originally seeded in culture is shown. The transplantation assay demonstrated a synergistic effect of soluble GFRα1 and bFGF on expansion of C57 × ROSA SSCs cultured with GDNF. Data are shown as means ± SEM for six recipient testes per time point. Most error bars do not extend beyond symbol. (B–E) Development and growth of germ cell clumps from 129/SvCP MACS Thy-1 pup testis cells. (Scale bar, 50 μm.) MACS Thy-1 cells on STO feeders after 5 h in culture (B), initiation of cell clump formation at 2 days (C), growth of germ cell clumps at 5 days (D), and continuous expansion of germ cell clumps at 5 months (E) are shown.