[Enrichment of type A1-A4 spermatogonia by flow cytometry]

To explore a method to isolate and purify the subtype of type A spermatogonial stem cells (SSCs).

We isolated spermatogonia by discontinuous density gradient centrifugation, sorted c-kit-expressed cells with the fluorescence-activated cell sorter (FACS), observed their ultrastructure by electron microscope, and performed immunohistochemistry to determine the expression of c-kit in the testis.

The c-kit positive cells constituted (18.65 +/- 1.69) % of the testis cells that were isolated by density gradient centrifugation, but made up only (3.16 +/- 0.84) % of those that were not (P < 0.01). The rates of recovery and viability of the c-kit positive cells sorted by FACS were (65.90 +/- 1.24)% and (85.60 +/- 1.14)%, respectively.

With c-kit as the marker, FACS can effectively isolate and purify the subtype of SSCs after preliminarily purified by discontinuous density gradient centrifugation.