Quantitative-PCR analysis of buffalo spermatogonia cultured on either experimental group cells (PB-GDNF-Sertoli) or control group cells (Sertoli with human GDNF) in vitro. Histograms showing the quantitative-PCR analysis of the germline-related marker DDX4 (A), the buffalo spermatogonia marker ZBTB16 (B), the inchoate buffalo spermatogonia marker NANOS2 (C) and the pluripotency marker POU5F1 in buffalo spermatogonia cultured on either PB-GDNF-Sertoli Cells or control Sertoli Cells (with human GDNF).