• 精子在PVP中暴露15、30和60分鐘後，其活力和形態均顯著受損，DNA碎片化和染色質結構異常增加，頂體反應精子的比例也隨之升高。此外，與未暴露於PVP的精子相比，粒線體膜電位高的精子數量顯著減少。
• 精子在PVP中暴露15分鐘後，PVP的有害作用顯著增強
• ICSI過程中，精子暴露於PVP的時間應限制在15分鐘內。

Prolonged exposure of human spermatozoa in polyvinylpyrrolidone has detrimental effects on sperm biological characteristics

Polyvinylpyrrolidone (PVP) has been utilized in intracytoplasmic sperm injection (ICSI) for immobilization and manipulation of spermatozoa. This study aims to determine the suitable time that sperm cells could be safely exposed to PVP during ICSI procedure. Twenty-five normal semen samples were prepared using the swim-up method and then were exposed to 10% PVP at different time intervals (15, 30 and 60 min). The effect of PVP on sperm parameters (viability and morphology), DNA fragmentation index (sperm chromatin dispersion test), chromatin quality (aniline blue, toluidine blue and chromomycin A3 staining), acrosome reaction, mitochondrial membrane potential and sperm ultrastructure was assessed at different time intervals. Our results showed that prolonged sperm exposure in PVP for 15, 30 and 60 min significantly affects viability and morphology with a concomitant increase in DNA fragmentation and abnormal chromatin structure, while the percentage of acrosome-reacted spermatozoa was additionally increased. In addition, the spermatozoa with high mitochondrial membrane potential were significantly decreased compared to unexposed spermatozoa to PVP. In conclusion, the detrimental effects of PVP were increased significantly following sperm exposure in PVP after 15 min. Therefore, the sperm exposure to PVP should be limited to less than 15 min during ICSI procedure.