title: [Enrichment of type A1-A4 spermatogonia by flow cytometry].
abstract: OBJECTIVE
  To explore a method to isolate and purify the subtype of type A spermatogonial stem cells (SSCs).
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  With c-kit as the marker, FACS can effectively isolate and purify the subtype of SSCs after preliminarily purified by discontinuous density gradient centrifugation.
authors.affiliation: Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China. baiyangunion@hotmail.com
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.forename: Zhe-Wei
authors.initials: ZW
authors.lastname: Ye
authors.forename: Fu-Qing
authors.initials: FQ
authors.lastname: Zeng
mesh_terms: D000818:Animals; D002469:Cell Separation / Q000379:methods*; D005434:Flow Cytometry / Q000379:methods*; D008297:Male; D008854:Microscopy, Electron; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013093:Spermatogonia / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D013737:Testis / Q000166:cytology / Q000378:metabolism
chemical_list: D019009:Proto-Oncogene Proteins c-kit