| Abstract: | The development of germ cells has not been entirely documented in the cat especially the transition phase ofthe gonocyte to the spermatogonial stem cell (G/SSC). The aims of study were to examine testicular developmentand to identify the G/SSC transition in order to isolate and culture SSCs in vitro. Testeswere divided into 3 groups according to donor age (I, < 4 months; II, 4–6 months; and III, > 6 months).In Exp. 1, we studied testicular development by histology, transmission electron microscopy andimmunohistochemistry. In Exp. 2, we determined the expression of GFRα-1, DDX-4 and c-kit and performed flowcytometry. The SSCs isolated from groups II and III were characterized by RT-PCR and TEM (Exp. 3).Chronological changes in the G/SSC transition were demonstrated. The size, morphology and ultrastructure ofSSCs were distinguishable from those of gonocytes. The results demonstrated that group II contained thehighest numbers of SSCs per seminiferous cord/tubule (17.66 ± 2.20%) and GFRα-1+ cells (14.89 ±5.66%) compared with the other groups. The findings coincided with an increased efficiency of SSC derivationin group II compared with group III (74.33 ± 2.64% vs. 23.33 ± 2.23%). The colonies expressedmRNA for GFRA1, ZBTB16, RET and POU5F1.Our study found that the G/SSC transition occurs at 4–6 months of age. This period is useful for isolation andimproves the establishment efficiency of cat SSCs in vitro. |
