Fig. 4.

Impact of CXCR4 signaling on maintenance of SSCs in primary cultures of undifferentiated spermatogonia. (A) Representative images of western blot analysis for CXCL12 protein in lysates and conditioned medium from STO and mitotically inactivated (mt) STO feeder cells. TUBB1 was used as a loading control. (B) Quantitative comparison of total germ cell numbers in primary cultures of undifferentiated spermatogonia after 7 days of treatment with the CXCR4-specific inhibitor AMD3100 or vehicle (control). (C) Representative images of recipient mouse testes 2 months after transplantation with lacZ-expressing primary cultures of undifferentiated spermatogonia treated with vehicle or AMD3100 for 7 days. Scale bars: 2 mm. (D) Quantitative comparison of SSC numbers in primary cultures of undifferentiated spermatogonia after 7 days of treatment with AMD3100 or vehicle, using functional germ cell transplantation analysis (12 total recipient testes). (E) Quantitative comparison of the percentage of proliferative cells (EdU⁺) within the CXCR4⁺ fraction of primary cultures of undifferentiated spermatogonia treated with the AMD3100 or vehicle (control). (F) Quantitative comparison of the percentage of apoptotic (TUNEL⁺) cells within the CXCR4⁺ fraction of undifferentiated primary cultures treated with AMD3100 or vehicle (control) for 3 days. All data are means ± s.e.m. for three different cultures. *Significant difference at P<0.05.