Enhanced penetration of zona-free hamster ova by sperm prepared by Nycodenz  and Percoll  gradient centrifugation

Serafini, P.; Blank, William; Tran, Cuong; Mansourian, Mourad; Tan, T.; Batzofin, Joel

doi:10.1016/s0015-0282(16)53356-1

Cited by 20 publications

(5 citation statements)

References 9 publications

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“…Both continuous and discontinuous Nycodenz gradients were evaluated, of which a four-layer discontinuous gradient was found to produce populations of highly motile spermatozoa with better yields and survival than either swim-up or Percoll ® gradients from oligozoospermic and asthenozoospermic semen samples [11,59]. Compared with the conventional swim-up procedure from a pelleted sperm population, the use of Nycodenz also seems to be superior regarding sperm penetration into zona-free hamster eggs [60]. Thus, this technique has clearly great potential in the preparation of motile spermatozoa from poor quality semen for IVF use and warrants further investigation.…”

Section: Sperm Separation Techniquesmentioning

confidence: 99%

Sperm preparation for ART

Henkel

Schill

2003

Reprod Biol Endocrinol

423

175

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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.

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Section: Sperm Separation Techniquesmentioning

confidence: 99%

Sperm preparation for ART

Henkel

Schill

2003

Reprod Biol Endocrinol

423

175

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“…It has been suggested that Percoll-separated spermatozoa from subfertile men have enhanced capacity to penetrate ZFHO (Serafini et al, 1990) and to fertilize in vivo (Pardo et al, 1989) and in vitro (Hyne etal., 1986). Different results have been reported for spermatoza from abnormal semen.…”

Section: Discussionmentioning

confidence: 99%

Human spermatozoa selected by Percoll gradient or swim-up are equally capable of binding to the human zona pellucida and undergoing the acrosome reaction

Morales

Vantman

Barros³

et al. 1991

Human Reproduction

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Several techniques have been used for selecting motile spermatozoa including Percoll and albumin gradients, swimup, and glass wool filtration. A high yield of motile spermatozoa as well as an enhancement of motility are the most desirable features of a practical method. An equally important consideration is whether or not these techniques select functionally normal spermatozoa. In this study we have compared two methods for separation of motile cells, swimup and Percoll gradient. Normal semen samples from 12 different men were used in this study. Each sample was simultaneously processed by swim-up and Percoll gradient using modified Tyrode's medium. After the sperm concentration was adjusted to 1 x 10 7 spermatozoa/ml, the suspensions were incubated at 37°C, 5% CO 2 in air. In each suspension the percentage of sperm recovery, percentage of motile spermatozoa, percentage of acrosome reacted spermatozoa (either spontaneously or stimulated with human follicular fluid), percentage of zona-free hamster oocytes penetrated, and number of spermatozoa bound to the human zona pellucida were determined. The results obtained indicated that the percentage of sperm recovery was higher with the Percoll gradient than with the swim-up procedure (P < 0.001). However, no significant differences were found between these two sperm populations in the percentage of motile cells, in the percentage of acrosome reacted spermatozoa, and in the percentage of zona-free hamster oocytes penetrated. In addition, the number of spermatozoa bound per zona pellucida was similar for spermatozoa selected by Percoll or swim-up. We conclude that there were no functional differences between the spermatozoa selected by either method.

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“…Bolton & Braude, 1984;Marrs et al, 1988) Early 1990s Percoll gradients made from polyvinyl propylene (PVP)-coated silica and various buffers used for spermatozoa of various species e.g. human (Serafini et al, 1990); boar (de Vries & Colenbrander, 1990) Late 1990s…”

Section: Recent Advances In Sperm Handling For Livestock Speciesmentioning

confidence: 99%

Reproduction biotechnologies in germplasm banking of livestock species: a review

Morrell

Mayer

2017

Zygote

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Many biotechnologies are currently used in livestock breeding with the aim of improving reproductive efficiency and increasing the rate of genetic progress in production animals. Semen cryopreservation is the most widely used cryobiotechnology, although vitrification techniques now allow embryos and oocytes to be banked in ever-increasing numbers. Cryopreservation of other types of germplasm (reproductive tissue in general) is also possible, although the techniques are still in the early stages of development for use in livestock species. Although still in their infancy, these techniques are increasingly being used in aquaculture. Germplasm conservation enables reproductive tissues from both animals and fish to be preserved to generate offspring in the future without having to maintain large numbers of living populations of these species. However, such measures need careful planning and coordination. This review explains why the preservation of genetic diversity is needed for livestock and fish, and describes some of the issues involved in germplasm banking. Furthermore, some recent developments in semen handling leading to improved semen cryopreservation and biosecurity measures are also discussed.

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Enhanced penetration of zona-free hamster ova by sperm prepared by Nycodenz and Percoll gradient centrifugation

Cited by 20 publications

References 9 publications

Sperm preparation for ART

Sperm preparation for ART

Human spermatozoa selected by Percoll gradient or swim-up are equally capable of binding to the human zona pellucida and undergoing the acrosome reaction

Reproduction biotechnologies in germplasm banking of livestock species: a review

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