Effects of stem cell factor and granulocyte macrophage-colony stimulating factor on survival of porcine type A spermatogonia cultured in KSOM

Spermatogenesis is initiated with the divisions of the type A spermatogonia l stem cells; however, the regulation of this stem cell population remains unknown. In order to obtain a better understanding of the biology of these cells, type A spermatogonia were isolated from 80-day-old pig testes by sed imentation velocity at unit gravity. The cells were cultured for up to 120 h in Dulbecco's modified Eagle's medium/Ham's F-12 medium (DMEM/F12) or a p otassium-rich medium derived by the simplex optimization method (KSOM). At the end of the 120-h culture period, 30-50% of the spermatogonia were viabl e in KSOM, whereas in DMEM/F12 very few cells survived. Using KSOM as the c ulture medium, the effects of stem cell factor (SCF) and granulocyte macrop hage-colony stimulating factor (GM-CSF) were studied. SCF significantly enh anced the percentage of cell survival at 100 ng/ml but not at lower concent rations. In comparison, CM-CSF promoted survival at relatively low concentr ations (0.01, 0.1, and 1 ng/ml). At a higher dose (10 ng/ml), a significant reduction in percentage of cell survival was observed. The combination of SCF with CM-CSF had no significant effect on the percentage survival of typ e A spermatogonial cells. These data indicate that SCF and GM-CSF play a ro le in the regulation of survival and/or proliferation of type A spermatogon ia.