Received March 03, 2013
Accepted April 13, 2013

Objective: To compare the DNA fragmentation of semen samples established by TUNEL after incubation in PVP at different time periods and temperature conditions. Methods: Semen analysis and DNA fragmentation assays (TUNEL) were performed. Two groups were established: (A) Normal TUNEL Q20% and (B) Abnormal TUNEL >20%. TUNEL was performed in: neat (T0), post-gradient/swim-up (TG/TS), 1 hour post-gradient/swim-up (TG1/TS1), and 2 hours post-gradient/swim-up (TG2/TS2) samples at room temperature or 37°C, and in TG2/TS2 samples after 30, 60, and 90 minutes of incubation in PVP at 37°C. TG and TS (RT and 37°C) aliquots after 24 hours of incubation were assessed. Results: TUNEL levels were significantly reduced after gradient and swim-up separation relative to neat values. After gradient, in group A, TUNEL levels were significantly higher in the TG2-90 hours at RT and TG2-30 at 37°C. Samples did not reach abnormal levels. In group B, TUNEL levels were significantly higher in TG2+60 at RT and TG2-30 at 37°C. After swim-up, in group A, TUNEL levels were significantly higher in TS2-30 hours at RT and 37°C. In group B, TUNEL levels were significantly higher in TS2 at RT and 37°C. Conclusions: Sperm DNA fragmentation significantly decreased after centrifugation gradient and swim-up, regardless of the initial levels of the sample. Samples with TUNEL>20% were more susceptible to a significant increase in DNA fragmentation over time. Samples after gradient and incubated at room temperature were lesser susceptible to a significant increase in DNA fragmentation. These data may be relevant for sperm preparation for ICSI.