An intrauterine insemination-ready cryopreservation method compared with sperm recovery after conventional freezing and post-thaw processing

Objective: To test a sucrose-glycerol cryoprotectant for IUI-ready sperm preparation. Design: Semen aliquots from normozoospermic donors either were subjected to conventional semen freezing (TES and Tris yolk buffer in 7.4% final glycerol) with post-thaw processing or were preprocessed and frozen in HEPES-buffered human tubal fluid with 1% human serum albumin, 4% sucrose, and 6% glycerol. All aliquots were cooled to 4°C, exposed to liquid nitrogen vapors, and stored in liquid nitrogen. Aliquots from each were processed by centrifugation resuspension or by centrifugation in Percoll (Pharmacia, Alameda, CA) before sperm parameters were analyzed. Setting: University-based andrology laboratory. Main Outcome Measure(s): Recovery of motile sperm. Result(s): Percoll processing produced preparations with higher percentages of motile cells; however, cryopreserved sperm had a lower recovery of motile sperm compared with Percoll-processed fresh semen or centrifugation/resuspension-processed fresh or frozen samples. The percentages of sperm with normal morphologies were significantly increased in the IUI-ready samples compared with samples frozen conventionally. The IUI-ready Percoll-processed sample produced the best results, with a final mean motility of 36% and an overall yield of motile sperm of 17.4%. Conclusion(s): The sucrose-glycerol-based cryoprotectant produced an IUI-ready preparation with motile sperm recovery comparable to that of conventional semen cryopreservation but with improved percent morphology.