Presentation Authors: Lona Vyas*, London , United Kingdom, Sheena Lewis, Belfast, United Kingdom, Tharu Tharakan, Channa Jayasena, Suks Minhas, Jonathan Ramsay, London, United Kingdom
Introduction: There is increasing evidence that the integrity of sperm DNA may be associated with recurrent miscarriage and failure of implantation. The objective of this study was to determine the DNA quality of testicular versus ejaculated sperm and secondary outcomes for single and double strand breaks, with the use of the Comet assay.
Methods: 59 men with persistently raised DNA fragmentation from couples who had failed cycles of intracytoplasmic sperm injection (ICSI) with ejaculated sperm underwent testicular sperm extraction. Results were also compared with 76 fertile donors. Sperm DNA fragmentation was measured by alkaline Comet assay to assess double plus single stranded breaks and neutral Comet assay to determine double stranded breaks only.Â The main outcome measures included comparison of single stranded break (SSB) as well as both double stranded breaks (DSB) and SSB, in ejaculates and with testicular sperm. Average Comet scores (ACS), Low Comet scores (LCS) and High Comet scores (HCS) were determined. Comparisons were made for each of these parameters from ejaculated and testicular sperm from infertile men with fertile donors. In 10 infertile men ejaculate comparison was made between single stranded DNA abnormalities compared to single and double stranded abnormalities.
Results: For total DNA damage ejaculate ACS (%) from infertile men was 39.9+/- 1.3 versus 17.9+/-1.3 in testicular sperm and 14.8+/- 0.6 from ejaculates from fertile donors (P < 0.001). _x000D_
Ejaculate LCS (%) from infertile men was 34.7+/- 2.7 versus 77.3+/-2.4 from testicular sperm and 90.2+/- 1.0 from ejaculates from fertile donors. _x000D_
Ejaculate HCS (%) from infertile men was 29.1+/- 2.9 v 8.8+/-1.8 from testicular sperm and 1.9+/-0.4 from ejaculates of fertile donors (P < 0.001). _x000D_
Comparison of infertile with fertile ejaculate was significant for all 3 groups of scores (P < 0.001)._x000D_
The comparison of SSB only v SSB plus DSB in testicular sperm demonstrated ACS (%) 10.6+/-1.2 v 14.7+/-0.9; LSC (%) 91.3+/- 2.0 v 92.2+/-1.4; HSC (%) 4.4+/-1.2 v 1.89+/-0.5 (P>0.05)._x000D_
The total sperm DNA damage in testicular sperm from infertile men is not significantly different from ejaculated sperm from fertile donors (P=0.08). However, DSB made up most DNA damage in testicular sperm and only half of the damage observed in ejaculated sperm.
Conclusions: This data provides novel and compelling evidence that testicular sperm from infertile men has no significant difference in Comet score compared to fertile donors. DNA damage in testicular sperm is all double stranded compared to only half of DNA damage in ejaculated sperm in this subgroup.