Frozen-thawed spermatozoa from oligozoospermic ejaculates are susceptible to in situ DNA fragmentation in polyvinylpyrrolidone-based sperm-immobilization medium

Objective: To elucidate the effect of sperm immobilization media that are and are not based on polyvinylpyrrolidone (PVP) on the DNA integrity of fresh and frozen-thawed spermatozoa during standard intracytoplasmic sperm injection (ICSI) conditions. Design: Experimental prospective study. Setting: Embryology research laboratory. Patient(s): Forty-six ejaculates from normozoospermic and oligozoospermic men. Intervention(s): Assessment of sperm DNA fragmentation by single-cell gel electrophoresis assay. Main Outcome Measure(s): DNA integrity of fresh and frozen-thawed spermatozoa from normozoospermic and oligozoospermic ejaculates exposed to PVP-based and non-PVP-based media. Result(s): Exposure of fresh and frozen thawed spermatozoa from normozoospermic and oligozoospermic ejaculates to PVP-based medium in an ICSI dish for 30 minutes statistically significantly increased the DNA fragmentation. In contrast, the extent of DNA fragmentation in non-PVP-based medium did not statistically significantly differ from control. Conclusion(s): A PVP-based medium can induce a statistically significant amount of sperm DNA fragmentation in an ICSI dish, and frozen-thawed sperm from oligozoospermic ejaculates are more susceptible to in situ DNA fragmentation.