ABSTRACT
The objective of this study was to compare the motility, morphology, and levels of DNA fragmentation of spermatozoa subjected to conventional swim-up or cumulus matrix (CM) sperm selection. Semen samples were collected from 60 normozoospermic men at a private hospital between December 2021 and March 2022. After liquefaction, semen samples were separated into two portions - one part was subjected to conventional swim-up preparation and the remaining spermatozoa were subjected to CM selection. The CM was obtained by mechanical isolation from healthy donor oocytes. Semen analysis and evaluation of sperm were performed according to WHO 6th Edition Laboratory Manual and Kruger's strict criteria, respectively. Sperm DNA fragmentation (SDF, %) of the two preparations was evaluated using Halosperm G2 detection kit (Halotech, Madrid, Spain). Wilcoxon rank-sum test was used to compare the characteristics of spermatozoa obtained by the two preparations. Spermatozoa selected by CM showed significantly better rapidly progressive motility (43.5% vs. 30.6%, respectively, p<0.001), higher percentage of morphologically normal forms (14.0% vs. 9.0%, respectively, p<0.05), and lower levels of SDF (26.0% vs. 45.0%, p<0.05) in comparison to those prepared by conventional swim-up. Moreover, the incidence of multiple sperm defects was considerably lower in the samples that underwent CM selection compared to those that did not (30.0% vs. 49.0%, respectively, p<0.05).The selection by CM significantly increases sperm motility and reduces morphologically abnormal spermatozoa and DNA fragmentation rates in comparison to the conventional swim-up preparation. The application of this selection technique may increase chances of successful IVF outcomes.
ABSTRACT
BACKGROUND: Sperm abnormalities may negatively affect embryo development. OBJECTIVES: To determine the influence of sperm abnormalities (morphology, motility, DNA fragmentation) on embryo morphokinetic variables and clinical outcome of conventional IVF. MATERIALS AND METHODS: Participants were 86 couples undergoing in vitro fertilization (IVF). Sperm morphology was evaluated according to the strict criteria proposed by Kruger/Tygerberg. CASA system was applied for sperm motility assessment. Sperm DNA fragmentation was assessed by the chromatin structure assay (SCSA). Morphokinetic parameters were determined in 223 embryos obtained from conventional IVF only and cultured in a single-step medium using time-lapse imaging technology. RESULTS: Time-lapse variables from the initial embryo development, such as time of pronuclei fading (tPNf) and time for two cells (t2), were those more strongly related with abnormalities of sperm motility, morphology, and DNA fragmentation. Sperm morphological abnormalities rather than sperm motility were more closely associated with embryo morphokinetics. Sperm head defects were mainly correlated with the last stages of embryonic development (t9 to tHB), sperm midpiece defects with intermediate cleaving embryos (t5-t9), and sperm tail defects with the initial stages of embryonic development (tPNa-t4). Excess residual cytoplasm was positively correlated with all embryo morphokinetic parameters except t2 and tM. Absence of acrosomes, pinheads, coiled tails, and multiple sperm morphological defects correlated negatively with time-lapse embryo morphokinetic variables. DISCUSSION: A large number of sperm-related variables, including frequency of specific morphological defects, morphological indexes, DNA fragmentation and motility, and time-lapse embryo variables, such as time intervals based mainly of 15 time points were recorded. CONCLUSION: There were strong associations between specific sperm defects of the head, midpiece, and tail with certain stages of embryonic development from observation of pronuclei to the hatched blastocyst. Coiled tail, cumulative head defects, and multiple abnormalities index (MAI) were associated both with embryo morphokinetics and the implantation success.
