Sperm biological characteristics improves when sperm preparation is done before cryopreservation in varicocele patients

BACKGROUND: Sperm cryopreservation is a process that involves preserving sperm cells for future use. Prior to freezing, sperm preparation methods like density gradient centrifugation (DGC) are typically performed to improve sperm quality. OBJECTIVE: To compare two sperm freezing methods, with and without seminal fluid, in normal and varicocele patients, focusing on reactive oxygen species (ROS) levels and sperm DNA fragmentation. MATERIALS AND METHODS: Forty samples from individuals with normal (n=20) and varicocele (n=20) were collected through ejaculation. Each sample was divided into two groups for analysis. One group DGC was performed pre-freezing and another group DGC was done post-freezing. Evaluations were conducted on sperm parameters, DNA fragmentation index, and ROS generation. RESULTS: In the normal group, progressive motility in Fresh Freeze DGC (19.55 ± 12.90) was lower than Fresh DGC Freeze (32.45 ± 12.86), although viability, morphology, DNA fragmentation and ROS production remained unchanged. Fresh Freeze DGC (44.25 ± 11.38) and Fresh DGC Freeze (53.58 ± 11.41) differed substantially in the varicocele group for viability assessment, whereas other parameters did not change in this group. CONCLUSION: It is recommended to prepare sperm before freezing to avoid potential issues with sperm not tolerating the centrifugation process. Removing seminal fluid before freezing can lead to better sperm parameters in both normal and varicocele groups.