Abstract: Objective To establish a quick and accurate technique of identifying the pachytene spermatocytes,round spermatids and elongating and condensing spermatids during STA-PUT velocity sedimentation. Methods Using STA-PUT velocity sedimentation method to isolate the pachytene spermatocytes, round spermatids and elongating and condensing spermatids from mouse testes.To determine the cell populations’ distribution ,each tube of cell fraction was then partially transfered to the 96 plate well ,and each well was added with acridine orange dye.Then each well was analyzed using fluorescence microscopy. Results The 3 types of spermatogenic cells can be identified quickly and accurately by it’s specific cytoplasm/nucleus character using the acridine orange dye staining under fluorescence detection. Conclusions A rubust method to quickly and accurately determine the pachytene spermatocytes,round spermatids and elongating and condensing spermatids during STA-PUT velocity sedimentation was successfully developed.

Key words: STA-PUT velocity sedimentation , pachytene spermatocytes, round spermatids, elongating and condensing spermatids, acridine orange