Sperm Selection: Effect on Sperm DNA Quality

Abstract

The selection of spermatozoa without DNA fragmentation and chromosomal diseases prior to assisted reproductive techniques helps to optimize the outcome of the treatment; in particular, sperm selection prior to in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) is crucial. In fact, although ICSI has been successfully and safely applied worldwide for almost 20 years, at the present time we have no real knowledge regarding the hypothetical long-term side effects on ICSI adults, given the increased likelihood of spermatozoa with defective nuclear content fertilizing oocytes.In the case of DNA damage, the basal sperm DNA fragmentation rate can be significantly reduced by some sperm processing procedures that improve the percentage of spermatozoa with normal chromatin structure by filtering out DNA-damaged spermatozoa. After this first step, new advances in micromanipulation can be performed to choose the "ideal" mature spermatozoa for ICSI, reducing potential damage to the gametes. In fact, it is possible to prevent fertilization by DNA-damaged and chromosomal-unbalanced spermatozoa by selecting ICSI sperm by maturation markers such as hyaluronic acid or other zona pellucida receptors. Furthermore, novel noninvasive imaging techniques can be valid tools for helping in the morphological selection of ICSI spermatozoa.

Whether sperm deoxyribonucleic acid fragmentation has an effect on pregnancy and miscarriage after in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis

“…Although the number of events in some studies is relatively small and the study characteristics are variable, tests for DNA damage and selection of undamaged sperm should be considered as part of the diagnostic and treatment pathways for those with recurrent pregnancy failure. Selecting ICSI sperm by maturation markers such as hyaluronic acid or other zona pellucida receptors, and/or by novel noninvasive imaging techniques, could help to prevent fertilization by DNA-damaged sperm (69). Further research is required into the mechanisms responsible for and preventing DNA damage, including antioxidant therapy.…”

Sperm DNA fragmentation is related to sperm morphological staining patterns

“…This is further important in the ICSI technique, as the single spermatozoon injected, which is only selected based on morphology and motility, may carry a high risk of having damaged DNA (Lopes et al, 1998;Parmegiani et al, 2014).…”

Variation of DNA Fragmentation Levels During Density Gradient Sperm Selection for Assisted Reproduction Techniques

“… 17 Whether DGC increases or decreases sDF is currently unclear. Indeed, although several studies have indicated that DGC improves the yield of DNA-intact spermatozoa, 18 others have reported no change or even a worsening of DNA quality in DGC-selected spermatozoa. 19 – 23 In addition, and most importantly, whether an eventual effect of DGC procedure on DNA damage impacts pregnancy achievement by ART is presently unknown.…”