Department of Obstetrics and Gynaecology

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Browsing Department of Obstetrics and Gynaecology by browse.metadata.advisor "De Windt-de Beer, Marie-Lena"

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    The effect of incubation time and temperature on sperm motility, human sperm DNA and assisted reproductive technologies (ART) outcome
    (Stellenbosch : Stellenbosch University, 2015-03) Van Zyl, Estee Alwelien; De Windt-de Beer, Marie-Lena; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Obstetrics and Gynaecology
    ENGLISH ABSTRACT: In all Assisted Reproductive Technologies (ART) procedures the semen sample is handled, processed, prepared and manipulated before use in the fertilization process. During these incubation times, the sperm cells are exposed to factors that may inflict damage to the sperm structure and DNA integrity, impair its functional abilities and subsequently lead to fertilization failure and poor ART outcome. Two of the very basic, but important factors that may have an impact on the sperm quality are time and temperature exposure. The primary objective of this study was to prospectively determine the effect of different incubation times and temperatures on motility and the DNA profile of the spermatozoa. Non-processed (n=36) and processed (n=33) semen samples were incubated for different time intervals (before: 20, 40, 60 minutes; after: 30, 60, 90 minutes) and at different temperatures (room temperature [RT] and 37°C). After incubation, sperm parameters were assessed, the CMA3 assay was applied to determine chromatin maturity and compaction and the TUNEL assay to assess the level of DNA fragmentation. The results showed that in the non-processed group, incubation led to a time-dependent, significant decline in the motility. The highest motility was seen at 20 minutes (37°C) and motility declined in a time-dependent manner. Incubation time and temperature did not affect the CMA3 and TUNEL values. Incubation of the processed sample led to a significant time-dependent decrease in the motility; 90 minutes (RT) had the lowest motility. The CMA3 and TUNEL values between the different incubation groups did not differ significantly. The secondary objective was to retrospectively investigate the effect of sperm incubation time after preparation on ART outcome. A total of 901 patient ART cycles (January 2010- December 2012) were included. Fertilization rates, embryo quality and pregnancy rates were examined. The results showed that the sperm incubation time before insemination between in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) differed significantly and the incubation time had a significant negative effect on the fertilization rates in IVF, but not in ICSI. Longer incubation times led to an unexpected significant improvement in the quality of day 2 embryos and were significantly associated with pregnancy failure in IVF and ICSI. These combined findings suggest that non-processed semen samples can be incubated at RT or 37°C, but for no longer than 40 minutes and, for IVF, processed samples should not be incubated for longer than 60 minutes at RT or 37°C. The ICSI sample should not be incubated for more than 60 minutes although longer incubation times do not seem to influence the results for IVF. It can therefore also be concluded that sperm incubation time before insemination should be closely monitored, especially in IVF cycles.