Co-incubation of spermatozoa with human follicular fluid reduces sperm DNA fragmentation by mitigating DNase activity in the seminal plasma

Abstract

To examine theeffect of co-incubating spermatozoa with human follicular fluid (HFF) on the rate of sperm DNA fragmentation. This prospective study used semen (n = 23) and HFF from oocyte donors (n = 23). Liquified semen was divided into four aliquots: (1) neat semen (NEAT), (2) seminal plasma removed and replaced with sperm media (HTF) containing 0% (FF0), (3) 20% (FF20), or (4) 50% (FF50) HFF. Sperm motility and DNA fragmentation (SDF) were assessed following 24h of incubation at 37°C. Pro-oxidant capacity of HFF and seminal plasma and the effect of HFF on seminal plasma DNase activity was assessed in a sub-sample of 10 ejaculates. Sperm motility was higher after 3h of incubation in media that contained HFF compared to the NEAT sample or when sperm was diluted in media without HFF. r-SDF (increase of SDF per time unit) values after 24h of incubation for NEAT, FF0, FF20 and FF50 were 0.91, 0.69, 0.25 and 0.36, respectively. While pro-oxidant capacity of seminal plasma samples showed large variation (mean: 94.6 colour units; SD 65.4), it was lower and more homogeneous in FF samples (mean: 29.9 colour units; SD: 6.3). Addition of HFF to seminal plasma appeared to inhibit DNase activity. While differences exist in the pro-oxidant capacity of seminal plasma of patients, sperm DNA integrity was preserved with addition of HFF to sperm media, irrespective of the level of pro-oxidant capacity. DNase activity in the original seminal plasma was abolished after HFF co-incubation.