Sperm preparation for ART.
Ralf Henkel,Wolf-Bernhard Schill +1 more
TLDR
Sperm separation methods that yield a higher number of motile spermatozoa are glass wool filtration or density gradient centrifugation with different media and caffeine, pentoxifylline and 2-deoxyadenosine are substances that were used to stimulate motility.Abstract:
The onset of clinical assisted reproduction, a quarter of a century ago, required the isolation of motile spermatozoa. As the indication of assisted reproduction shifted from mere gynaecological indications to andrological indications during the years, this urged andrological research to understand the physiology of male germ cell better and develop more sophisticated techniques to separate functional spermatozoa from those that are immotile, have poor morphology or are not capable to fertilize oocytes. Initially, starting from simple washing of spermatozoa, separation techniques, based on different principles like migration, filtration or density gradient centrifugation evolved. The most simple and cheapest is the conventional swim-up procedure. A more sophisticated and most gentle migration method is migration-sedimentation. However, its yield is relatively small and the technique is therefore normally only limited to ejaculates with a high number of motile spermatozoa. Recently, however, the method was also successfully used to isolate spermatozoa for intracytoplasmic sperm injection (ICSI). Sperm separation methods that yield a higher number of motile spermatozoa are glass wool filtration or density gradient centrifugation with different media. Since Percoll® as a density medium was removed from the market in 1996 for clinical use in the human because of its risk of contamination with endotoxins, other media like IxaPrep®, Nycodenz, SilSelect®, PureSperm® or Isolate® were developed in order to replace Percoll®. Today, an array of different methods is available and the selection depends on the quality of the ejaculates, which also includes production of reactive oxygen species (ROS) by spermatozoa and leukocytes. Ejaculates with ROS production should not be separated by means of conventional swim-up, as this can severely damage the spermatozoa. In order to protect the male germ cells from the influence of ROS and to stimulate their motility to increase the yield, a number of substances can be added to the ejaculate or the separation medium. Caffeine, pentoxifylline and 2-deoxyadenosine are substances that were used to stimulate motility. Recent approaches to stimulate spermatozoa include bicarbonate, metal chelators or platelet-activating factor (PAF). While the use of PAF already resulted in pregnancies in intrauterine insemination, the suitability of the other substances for the clinical use still needs to be tested. Finally, the isolation of functional spermatozoa from highly viscous ejaculates is a special challenge and can be performed enzymatically to liquefy the ejaculate. The older method, by which the ejaculate is forcefully aspirated through a narrow-gauge needle, should be abandoned as it can severely damage spermatozoa, thus resulting in immotile sperm.read more
Citations
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Journal ArticleDOI
The role of free radicals and antioxidants in reproduction.
TL;DR: The role of free radicals and oxidative stress in the pathophysiology of human reproduction is summarized and evidence in the literature on the beneficial effects of oral antioxidant supplementation in male infertility is summarized.
Journal ArticleDOI
Oxidative stress and its implications in female infertility – a clinician's perspective
TL;DR: This review discusses the sources of ROS in media used in IVF-embryo transfer and strategies to overcome OS in oocyte in-vitro maturation, in-Vitro culture and sperm preparation techniques.
Journal ArticleDOI
Oxidative stress in an assisted reproductive techniques setting.
TL;DR: Many modifiable conditions exist in an ART setting that may aid in reducing the toxic effects of ROS, and the main objective of this review is to provide ART personnel with all the necessary information regarding the development of oxidative stress in anART setting.
Journal ArticleDOI
Prevention of oxidative stress injury to sperm
TL;DR: Spermatozoa are sensitive to OS because they lack cytoplasmic defenses, and the sperm plasma membrane contains lipids in the form of polyunsaturated fatty acids, which are vulnerable to attack by ROS.
Journal ArticleDOI
Effect of reactive oxygen species produced by spermatozoa and leukocytes on sperm functions in non-leukocytospermic patients
Ralf Henkel,Eva Kierspel,T. Stalf,Claas Mehnert,Roelof Menkveld,Hans-Rudolf Tinneberg,Wolf-Bernhard Schill,Thinus F. Kruger +7 more
TL;DR: The origin of ROS seems to have an influence on the site of the damage in sperm functions, and the threshold given by the World Health Organization (WHO) should be re-evaluated.
References
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Book
The Physiology of Reproduction
Ernst Knobil,J. D. Neill +1 more
TL;DR: The gametes, fertilization and early embryogenesis the reproductive systems - the female, the male the pituitary and the hypothalmus, and the reproductive processes and their control.
Journal ArticleDOI
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Salvador Moncada,Annie Higgs +1 more
TL;DR: The discovery that mammalian cells generate nitric oxide, a gas previously considered to be merely an atmospheric pollutant, is providing important information about many biologic processes.
Journal ArticleDOI
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TL;DR: How different forms of nitric oxide synthase help confer specificity and diversity on the effects of this remarkable signaling molecule is reviewed.
Journal ArticleDOI
Development of an assay to assess the functional integrity of the human sperm membrane and its relationship to other semen characteristics
TL;DR: The hypoosmotic swelling technique to evaluate the functional integrity of the sperm membrane appears to give high repeatability and accuracy and is closely correlated to the in-vitro fertilizing ability of spermatozoa.
Journal ArticleDOI
NO at work
TL;DR: NO is a double-edged sword, beneficial as a messenger or modulator and for immunologic self-defense, but potentially toxic in several different scenarios with factors such as oxidative stress, generation of reactive oxygen intermediates (ROls), and deficient anti- oxidant systems.
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