Presentation on theme: "Semen preparation techniques for ART"— Presentation transcript:
1Semen preparation techniques for ART Gülnaz Şahin, MDEge University Family Planning and Infertility Research and Treatment Center
2The onset of clinical assisted reproduction, a quarter of a century ago, required the isolation of motile spermatozoaSince the birth of Louise Brown on 25 July 1978 and the subsequent onset of assisted reproduction in the human, scientists and clinicians were more and more urged to improve sperm separation techniques as the percentage of andrological cases increased rapidlyNearly 50% of infertile couples have contributing male factor
3The first sperm separation methods were one or two washing procedures with subsequent resuspension of the male germ cells (1-3)1. Edwards RG, Bavister BD, Steptoe PC: Early stages of fertilization in vitro of human oocytes matured in vitro. Nature 19692. Edwards RG, Steptoe PC, Purdy JM: Establishing full term human pregnancies using cleaving embryos grown in vitro. Br J Obstet Gynaecol 19803. Lopata A, Brown JB, Leeton JF, Talbot JM, Wood C: In vitro fertilization of preovulatory oocytes and embryo transfer in infertile patients treated with clomiphene and human chorionic gonadotropin. Fertil Steril 1978
4Researchers then described a single wash followed by a swim-up procedure from the cell pellet.Following these first reports on human sperm separation, more sophisticated methods were developed to obtain sufficient amounts of motile, functionally competent spermatozoa for IVF.Mahadevan M, Baker G: Assessment and preparation of semen for in vitro fertilization. In: Clinical In Vitro Fertilization Edited by:Wood C, Trounson A. Springer-Verlag, Berlin; 1984
5On principle, these techniques can be differentiated in migration, density gradient centrifugation and filtrationSwim-up (Mahadevan and Baker, 1984)Percoll density gradient centrifugation (Gorus & Pipeleers, 1981)Glass-wool (Paulson & Polakoski, 1977)Sephadex bead filtration (Lopez et al.,1993)
6The ideal sperm separation technique shouldbe quick,easy and cost-effective,isolate as much motile spermatozoa as possible,not cause sperm damage or nonphysiological alterations of the separated sperm cells,eliminate dead spermatozoa and other cells, including leukocytes and bacterias,eliminate toxic or bioactive substances like decapacitation factors or reactive oxygen species (ROS) and,allow processing of larger volumes of ejaculates.
7The quality of sperm samples is one of the factors determining successful assisted reproduction (Ombelet et al. 2003)
8Ejeculated semenViscous liquid composed of mixture of testicular, epididymal secretions containing spermatozoa and prostatic secretions produced at the time of ejeculation.This seminal plasma contains substances which inhibit capasitation and prevent fertilizationCapacitation of eutherian spermatozoa is essential for fertilization not only in vivo but also in vitro, and underlies the manipulation of spermatozoa for clinical invitro fertilization (IVF).
9The purposeConcentrate the motile spermatozoa in a fraction which is free of seminal plasma and debrisMaximalize the changes of fertilization to provide as many normally fertilized ooctes as possibleElemination of seminal PG, lymphokines, cytokines and infectious agentsReduce the number of free oxygen radicalsIt is essential for them to be able to achieve capasitation and their fertilizing ability
10Collection of spermThe male partner should collect semen into a sterile, clearly labelled disposible plastic jar with in a room adjecent to the IVF laboratoryThe time of sample collection should be recorded on the labelSemen should be prepared soon after liquefactionIf liquefaction delayed or specimen viscous; mixing the specimen 1:1 with medium may help or enzymatically liquefaction can be done (ie; α-amylase, hyolurinidase, tripsin based dissolving sol.)10 μl of the sample is taken to check sperm consentration and motility2 ml medium ve 5 mg alfa kimotripsin karıştırılır. Bu solüsyon semen ile karıştırılıp 37 c de 5 dk inkübe edilir. Sürenin uzaması sperm hasarı nedeniyle öneerilmez.
11Initial assesment of density and motility allow to choose the most appopriate method of sperm preparationThe choice of sperm preparation method depens on,the motile count, ratio between motile/immotile count, volume, presence of antibodies, agglutination
12ROS (reactive oxygen species) induced damage Morphologically abnormal spermatozoa with retained spermatid cytoplasm and leukocytes present within the ejaculate generate free radicals in vitroCentrifugation can be harmful to human spermatozoa (forses in excess of 800 g applied)Centrifugal pelleting of unselected human sperm populations often resulted in the generation of free radical or reactive oxygen species (ROS) within the sperm pellet that could irreversible damage to the spermatozoa that can impair—even totally destroy—their fertilizing cability.Aitken RJ, Clarkson JS.; J Androl.1988
13ROS induced damageROS are generated both by leukocytes present in semen and spermatozoaROS affect not only the sperm plasma membrane by causing phospholipid peroxidation, but also the sperm DNA by causing strand breaks that can be revealed by various tests of sperm DNA integrity*spermatozoa prepared by simple washing will definitely be at a much greater risk of contributing a defective genome to the embryo and could underlie the increased developmental failure of ICSI-derived embryos after the 8-cell stage when the embryonic genome is activated***Saccas et al, 1997, *Evenson et al.,1999**Shoukir et al, 1998)
14Swim-up Is still used largely in IVF laboratories around the world. Although its use among the male factor infertility group is very limited, the swim-up is still the standard technique for patients with normozoospermia and female infertility.This procedure has several variations
15Standart swim-up The methodology of conventional swim-up is based on the active movement of spermatozoa from the prewashed cell pellet into an overlaying medium. Typically, the incubation time is 60 minutes.
16Direct swim-up from liquefied semen A maximum recovery is obtained by using multiple tubes with small volumes of semen per tube, thus maximizing the combined total interface area between semen and culture medium.Mortimer suggested the use of 250 μl semen and 500 to 600 μl culture medium per tubePipette 2 ml medium, underneath semen, tightly cap tube and allow it to stand at room temp. Up to 2 hours. Harvest the resulting top and middle clouded layers into conical tube and spin it 200 g for 5 min. Remove supernatan and resuspend 2 ml medium, centrifuge again and resuspend 1 ml medium Gas the surface gently with 5% CO2 in air and store at room temp.
17Pellet and swim-upAlternatively, semen sample may be diluted and centrifuged and pellet overlaid with mediumUseful for viscous samplesNot recommended when motility is very poor or large degree of cellular contamination and debrisHas disadvantage of peroxidative damage during centrifugation with defective sperm and white cells*Yıkama sonrası elde edilen 0.5 ml örnek pipetlenerek homogen karışım elde edilir. 1 ml kültür sıvısı bu karışımın üzerine yavaşça bırakılarak 2 ayrı katman oluşturulur. Konik dipli tüpte 45 c açı verilerek %5 CO2 li ortamda 1 saat inkübe edilir.*Aitken RJ, 1990
18The sperm select system employs a high-purity preparation of 3000 kd sodium hyaluronate at a 1-mg/mL final concentration in culture medium.It has been shown a significantly higher percentage of motile spermatozoa and, the achievement of a higher pregnancy rate compare with traditional swim-up in a clinical IVF program*However, it has been shown to increase the calcium influx into spermatozoa and induce acrosome reactionIn a clinical IVF program, swim-up from semen into the hyaluronate solution gave a significantly higher percentage of motile spermatozoa compared with the traditional swim-up from a washed pellet method and allowed the achievement of a higher pregnancy rate (Wikland et al, 1987).* Wikland M et al.; A selfmigration method for preparation of sperm for in-vitro fertilization.Hum Reprod. 1987;2:191–195.
19Migration-sedimantation swim-up technique combined with a sedimentation stepspermatozoa swim up directly from liquefied semen into the supernatant medium and subsequently sediment in that inner cone within an hourZavos et al.proposed the use of a multi-chamber tube to retrieve functional spermatozoa for assisted reproductive techniques by means of a swim-up and sedimentation method.Zavos PM et al; Use of the multi-ZSC one-step standardized swimup method: recovery of high-quality spermatozoa for intrauterine insemination or other forms of assisted reproductive technologies. Fertil Steril 2000, 74:
20Density gradients Various gradient procedures It is rapid, relatively simple to performAbnormal sperm, immotile sperm and debris can largely eliminateGenerally the recovery of motile sperm is greater with gradients but the percentages of sperm with progressive motility is usually lower than with swim-up
22The ejaculate is placed on top of the density media with higher density and is then centrifuged for 15–30 minutesHighly motile spermatozoa move actively in the direction of the sedimentation gradient and can therefore penetrate the boundary quicker than poorly motile or immotile cells, thus, highly motile sperm cells are enriched in the soft pellet at the bottom1 ml %90 konsantrasyon üzerine 1 ml %40 kons.konur, en fazla 2 ml semen eklenip 20 dk santrifüj edilir. 600 g ve 18 dk rutindir. Dipte kalan 0.5 ml kısım üzerine 3 ml kültür mediumu ile yılanır.
23Density gradientsPercoll was withdrawn from clinical use by its manufacturer in 1996PVP-coated silica that can have deleterious effects on sperm membranes, and may affect subsequent fertilization events (De vos et al, 1997) because of high endotoxin levelsProducts contain silane-coated silica particles, adjusted for the osmolarity with polysucrose , have very low toxicity. All these replacement products are non-irritating and are approved for human in vivo use.Products contain silane-coated silica particles, adjusted for the osmolarity with polysucrose , have very low toxicity. All these replacement products are non-irritating and are approved for human in vivo use.
24Density gradientsDensity gradients protect the sperm from trauma of centrifugationHigh proportion of functional sperm can be recovereTwo or three step gradients are simple and highly effective in preparing motile sperm from suboptimal samplesIn general longer centrifugation time increases the recovery of both motile and immotile spermDebris, round cells, abnormal forms never reach the bottom of the tube because of their low density
25Density gradientsGradients with larger volumes result in improved filtration, but decreased yieldThree layers of mini-gradient improve filtration, recovery of sperm from severely oligospermic samplesSamples wiht large amont of debris should be distributed in smaller volumes over several gradientsSeverely asthenoozospermic samples,with normal density can also be distrubuted over a series of mini-gradients
26Density gradientsWith continuous gradients, there is a gradual increase in density from the top of the gradient to its bottom, whereas the layers of a discontinuous gradient show clear boundaries between each other
27Mini-gradient(95/70/50) Make layers with 0.3 ml f each sol:95,70,50 Dilute semen 1:1 with culture medium, centrifuge at 200 g for 10 minutesResuspend the pellet in 0.3 ml culture medium and layer over mini-gradientCentrifuge at 600 g, for minutesRecover the pellet, resuspend in 0.5 ml culture medium and assess count and motility. Proceed exactly as for two step gradient prep; either centrifuge at 200 g for 5 min and resuspended pellet, or layer over the pellet for a swim up
28Sedimantation method or layering under paraffin oil Useful for samples with very low counts and poor motilityVery effective in removing debris, requires several hours of preparationWash the sample by dilution and cent.twiceResuspend the pellet in a reduce volume of mediumLayer this suspansion under paraffin oil in a small petri dish, place in a desiccator and gas with 5% CO2Leave at room temp for 3-24 hours.Carefully aspirate motile sperm by using a fine drawn pipette
29Glass wool filtrationMotile spermatozoa are separated from immotile sperm cells by means of densely packed glass wool fibresPotential risks of the technique ; damages of the spermatozoa or the occurrence of glass wool fragments in the filtrate essentially depend on the kind of glass wool used and on the intensity of the washing prior to the filtration.uses the whole volume of the ejaculate and therefore yields a significantly higher total number of motile spermatozoa and do not required prewash stepit can also be used for patients with oligo- and/or asthenozoospermiaBorat, Silicat, QuartzHenkel R et al., J Assist Reprod Genet 1994Berger T et al., Fertil Steril 1985
30Glass wool filtrationglass wool filtration has been shown to eliminate leukocytes to an extent of up to 90%, this effect significantly contributes to a reduction of free radicals in the ejaculateGlass wool filtration like the density gradient centrifugation with PureSperm or the migration sedimentation technique significantly selects normally chromatin-condensed spermatozoa
31Semen preparation techniques for intrauterine insemination Boomsma CM, Heineman MJ, Cohlen BJ, Farquhar CSummaryThe effectiveness of specific sperm preparation techniques for increasing pregnancy rates in subfertile couples undergoing intrauterine insemination (IUI) is unknownSemen preparation techniques are used in assisted reproduction to separate sperm, which have a normal appearance and move spontaneously, from the fluid portion of the semen in which the sperm are suspended. It is known that white blood cells, bacteria and dead sperm in semen can produce oxygen radicals that can impair fertilization of the egg. This review found that there is insufficient evidence to recommend any specific sperm preparation technique for subfertile couples undergoing intrauterine insemination (a procedure which places sperm directly into the uterus) as there were no differences in pregnancy rates. More research is needed.Cochrane Reviews March 2004
32Which procedure for IUI? Swim-up/Gradient? Boomsma CM, Heineman MJ, Cohlen BJ, Farquhar C .Cochrane Reviews March 2004
33Which procedure for IUI? Swim-up/Gradient? Cochrane Database of Systematic Reviews, 2004
34Sperm processingSamples with an acceptable number of motile sperm ( > 20 millions / ml ) can be processed efficiently by sperm wash twice and swim-up.Poor quality semen samples should be processed using density gradient centrifugation DGC Morshedi M et al, 2003
35Sperm preparation for ICSI Combination of methods can be useExtremely oligospermic/asthenozoospermic samples cannot be prepared by density centrifugation or swim-up
36High-speed centrifugation and washing Cryptozoospermic samples which must be prepared for ICSI can be centrifuged directly at 1800 g for 5 minutes or diluted with medium and then centrifuged at 1800 g for 5 min.Wash the pellet with small volume of medium(0.5 ml) and centrifuge at 200 g for 5 min.Recover this pellet in a minimal volume of medium(20-50 μl), and overlay with mineral oilEvery semen has different characteristics and parameters. It is important to tailor prep technics to fit the parameters of the semen specimen. A trial prep prior to oocyte retrieval may be advisable in choosing the suitable tech.
37Sperm preparation for ICSI Extremely oligospermic/asthenozoospermic samples; 1. Centrifuge the whole sample, 1800 g, 5minutes, wash with medium, and resuspend the pellet in a small volume of medium2. Apply sample directly to the injection dish, without PVP,or add an aliquot suspension to a drop of HEPES buffered medium without PVP3. If possible, use the injection pipette to select a moving sperm with apparently normal morphology from this drop and transfer it into the PVP or into another drop of HEPES buffered medium4. If there is debris attached to the sperm, clean it by pipetting the sperm with the injection pipette5. It may sometimes be helpful to connect the sperm droplet to another small medium droplet by means of a bridge of medium, and allow motile sperm to swim out into the clean droplet
38No motile spermIt may possible to see slight tail movement in a medium drop without PVP.If absolutely no motile sperm are found, immotile sperm may be used. The fertilization rate with immotile sperm is generally lower. Previous assesment with a vital stain may be helpful before deciding ICSI treatment
39No motile spermTo date, two different approaches for the distinction between live and dead spermatozoathe initiation of motility as sign of vitality by means of stimulantsthe identification of live spermatozoa according to their membrane integrity by means of the hypo-osmotic swelling test (HOS test).
40PDE inhibitorAs pentoxifylline stimulates motility without altering the sperm membrane, it appeared as an ideal substance to initiate motility in immotile spermatozoaThis method was successfully used to identify live testicular and epididymal spermatozoa and live births are reportedSemen 1 ml yıkama mediumu ile dilüe edilir. 180 Mm,20 ul pentoxifilin(1 mg/ml) eklenir.15 dakika 37 C de inkübe edilir. 300 g de 10 dakika santrifüj edilir ve pellete 4 ml sperm yıkama mediumu eklenir. 300 g de tekrar 10 dk santrifüj edilir. Pellet resüspanse edilir, 15 dakika inkübasyondan sonra ICSI hazırlanır.Terriou P et al., J Assist Reprod Genet 2000, 17:Nodar F et al, Fertil Steril 1999, 71:
41HOS (hypo-osmotic swelling test) Assesses the osmoregulatory ability of the sperm, and the functional integrity of its membranesCan be used to discriminate viable sperm from non-viables in a sample which has zero motilityIn hyposmotic environment sperms react by swelling of the tail. Dead spermatozoa whose plasma membranes are no longer intact do not show tail swellingHypo-10 solution( 1 ml) ile 100 ul semen karıştırılıp 60 dk 37 c de beklenir.Jeyendrn RS, Van der Ven HH, et al. (1984):J Reprod Fertil 70:219–228.
42Fructoz ve sodium sitrat dehidrate, deioinize water(distile water) 150 mosm/L
43No motile spermShown significantly elevated fertilization and pregnancy rates when oocytes were injected with HOS-positive spermSperm immotility is significantly positively correlated with sperm DNA fragmentation*, the probability to select such DNA-damaged spermatozoa for ICSI is higherAccording to present knowledge, sperm DNA fragmentation might cause an impaired embryonic development and early embryonic death**Therefore, a careful examination and counselling of the patients seems mandatory, and fertilization with ICSI should not be performed at all cost*Henkel R et al, RBM Online 2003, 7:**Asch R et al, Hum Reprod 1995**Jurisicova A et al, Mol Hum Reprod 1996**Simerly C et al., In:Genetics of Human Male Fertility Edited by: Barratt C et al, Paris; 1997:**Aitken RJ et al, Biol Reprod 1998, 59:
44Abnormal headsIn cases with 100% abnormal head anomalies, the fertililization and implantation rates lower, individual judgment should be applied to each case, with several assessment of several different semen samplesGloboozospermia,100% head anomaly, where all sperm lack an acrosomal cap; debate continues as to whether it is ethically advisable to offer treatment to these man
45Retrograde ejeculation Bladder shoul emptied via catheter, approximately 20 ml of culture medium then installedAfter ejeculation, bladder is again emptied, entire sample centrifugedResulting pellet can then be resuspended in medium and processed on appopriate density gradients
46Retrograde ejeculation 1 gm bicarbonate PO night before and morningSplit the urine 10 ml. fractions and santrifugate at 300 g, 5 minResulting pellet can then be resuspended in medium and processed on appopriate density gradients
47Azoospermia: epididymal sperm Can be obtained by open microscopic surgery or by percutaneus puncture using by needle to aspirate fluidIf large numbers of sperm are found, they can processed by density gradient or swim-upSamples with fewer sperm can be washed and centrifuged with IVF medium, and concentrated sample is than added to microdroplets in the injection dish.
48Azoospermia: Testicular sperm Testicular tissue is obtained either by open biopsy or percutaneus fine-needle aspirationPlace tissue into a small petri dish of warm culture media with hepes, albuminDissect and squeeze tubules using fine gauge needlesTransfer raw suspension to a test tube and vortex for 30 sDepending on concentration, motility, amount of debris, either use directly after wash and resuspension or seperate on a density gredientLeave sperm to incubate to allow sperm to gain motility up to 24 hours in culture media with albumin at 37°C under 5% CO2for same day use, prepare plate for ICSI and leave at 37°C in Hepes buffered culture media with albumin
49enzimatic digestion or mechanical preparation of testicular tissue The optimal method of obtaining suitable sperm from testicular tissue is still under debateMechanical preparation by mincing andshredding *Enzimatic digestion by using collagenase **It has been shown no advantages one over the other preparation method***Testiküler doku materyali üzerine 1000IU/ml kollagenaz tip IV ve 25 mg/ml DNase içeren 1 ml . HEPES kültür sıvısı eklenir. Materyal konik tüpe alınır ve 1 saat %5 CO2 de bekletilir. Bu süre içinde dk.da bir hafifçe sallnır.En sonunda 5 dakika 50 g hızında santrifüjlenir( sıvı içerisine karışmış sperm hücrelerinin alttaki doku parçalarına yapışmasını engellemek için az ve kısa santrifüjlenir) Elde edilen solüsyon iki kere yıkanarak enzimlerin uzaklaşması sağlanır*Verheyen et al.; Hum Reprod, 1995**Salzbrunn et al.; Hum Reprod, 1996***V.Baukloh on behalf of German Sociaty for Human Repro. Biology;Hum Reprod,2002
50sperm morphology and genotype Abnormally small and large sperm heads are often associated with aneuploidy and diploidyIt has been shown that morphologically abnormal spermatozoa can carry normal karyotypes (Martin and Rademaker, 1988) and can produce normal offspringThis subject is a major area of current research
51Sperm DNA damageDNA damage in human spermatozoa is negatively correlated with pregnancy rates in both natural and assisted conception cycles and has been linked with both increased rates of miscarriage and diseases in the offspring(Aitken, 1999; Loft et al., 2003; Lewis and Aitken, 2005)
53Sperm cromatin condensation The degree of nuclear chromatin condensation can be assessed by various techniques such as aniline blue (Terquem & Dadoune, 1983), acridine orange (Tejada et al., 1984) or chromomycinCMA3 (Bianchi et al., 1993)Manicardi et al. (1995) and Sakkas et al. (1996) have indicated that in a normal semen sample CMA3 Fluorescence can be taken at <30%, while levels above these values would be indicative of a semen sample containing spermatozoa with abnormal chromatinCromomisin, indirect visualizasyon of protamine-deficient ,nicked and partially denatured DNA spermatozoa select. Fix preparates with methanol/glacial acetic acid, 4 C in 5 min than treat ecah slide for 20 min with 100ul CMMA3 so, evaluate using fluorescent microscopy
57Hammadeh ME. Int JAndrol.2001;24:360-368 The proportion of chromatin condensed spermatozoa increased after sperm processing with swim-up, PureSperm gradients centrifugation and glass-wool in comparison with the value observed in the native semen samplesThis increase was significantly shown higher after semen separation with glass-wool in comparison with traditional swim-upHowever, there were no significant differences in the fertilization, implantation and pregnancy rates of sperm prepared by means of swim-up, PureSperm or glasswool filtrationTheir conclution was, glass-wool filtration could be used as the first choice for semen preparation in an ICSI programme as the natural selection is bypassed. Swim-up and Pure Sperm should be used for semen processing in IVF programme
58Density gradient centrifugation separate spermatozoa according to their density and favours the isolation of the motile and normal morphological spermatozoa (Mortimer et al,1999)Differential gradient sperm separation method using Percoll is superior to the swim-up method for selecting sperm with normal morphology (Prakash et al.,1998)Sakkas et al. (2000) investigated the efficiency of the PureSperm, Percoll and swim-up preparation techniques to eliminate spermatozoa with nuclear anomalies. They indicated that both the PureSperm and Percoll techniques can enrich the sperm population by separating those with nicked DNA and with poorly condensed chromatinswim-up, resulted in a greater proportion of motile spermatozoa and eliminatedmainly tail abnormalities, whereas Percoll gradient separation selected overall-headed spermatozoa with good motility. (Le Lannou & Blanchard)
59Henkel et al (1994), demonstrated that glass-wool filtration results in a significant higher percentage of normal chromatin condensed spermatozoa compared with the ejaculateSoderlund & Lundin (2000) was also demonstrated that PureSperm-treated spermatozoa resulted in similar fertilization and pregnancy rates as using spermatozoa obtained after the swim-up procedure.
60(MACS) annexin V magnetic-activated cell sorting separation Successful fertilization requires a sperm plasma membrane with normal integrity and function (Flesch et al., 2000)The plasma membrane is one of the key structures in spermatozoa of infertile men displaying apoptotic features(Glander and Schaller, 1999)The phospholipid phosphatidylserine (PS), which is normally present on the inner leaflet of the plasma membrane, becomes externalized to the outer leaflet (Vermes et al., 1995), The externalization of PS is currently accepted as a membrane marker for early apoptosis (Martin et al., 1995)
61MACSAnnexin V is characterized by high affinity for PS and does not have the ability to pass the intact sperm membrane. Therefore, annexin V binding to spermatozoa characterizes disturbed integrity of the sperm membrane(Glander and Schaller, 1999),Colloidal super-paramagnetie microbeads (~50 nm in diameter) conjugated with annexin V have been shown to separate the dead and apoptotic spermatozoa by magnetic activated cell sorting (MACS), Cells exposing PS bound to these microbeads (annexin positive) are enriched to high extent within a column containing iron balls when placed in a very strong magnetic field. Cells with intact membranes remain unlabelled (annexin negative), and pass freely through the column (Miltenyi et al., 1990; von Schonfeldt et al., 1999)
62MACSThe combination of MACS with density gradient centrifugation (DGC) in a single sperm preparation protocol results in spermatozoa with superior quality (Said et al., 2005a)In general, MACS is a feasible and safe method that may be used to provide a high-quality sperm fraction (Glander et al., 2002; Grunewald et al., 2001; Paasch et al., 2003b, 2005)The high sperm recovery rate following advocates the use of this protocol as sperm preparation technique prior to assisted reproduction. Separating a distinctive population of nonapoptotic spermatozoa with intact membranes and subjecting it to IVF or ICSI is a step further in optimizing the outcome of assisted reproductionNevertheless, future experiments using animal models that evaluate embryo viability and genetic integrity would still be needed before the technique could be applied to human cases.
63PICSIHyaluronan (H) is a major constituent of the cumulus oophorous matrix and may play a critical role in the selection of functionally competent sperm during in vivo fertilization.The in vitro selection of sperm for ICSI is critical and may influence the developmental potential of the resulting embryo.Research has demonstrated that specific motile sperm attach to H and that such H-bound (HB) sperm carry enhanced levels of developmental maturity, sperm chromatin integrity and normal morphology. HB sperm may therefore contain increased levels of functional competence.The PICSI plate provides microdrops of H for sperm selection**** Gabor Huzsar,MD Yale UniversityK. C.Worrilow, H. T. Huynh, et al.; ASRM 2007 October OP
64PICSIAuthors suggests that the use of HB-sperm in ICSI may allow the isolation of sperm with potentially enhanced levels of functional competence, thereby exerting a positive paternal influence on preimplantation embryogenesis. The statistically significant reduced levels of fragmentation, increased cpr and decreased mr associated with the use of PICSI-derived embryos is promising.K. C.Worrilow, H. T. Huynh, et al.; ASRM 2007 October OP
66The highes quality spermatozoa in the ejaculate are the most electronegative (Kirchhoff and Schroter, 2001; Giuliani et al., 2004; Ainsworth et al., 2005) and spermatozoa can be separated from other contaminating electronegative cells (such as leukocytes)by their small cross-sectional sizerapid (5 min), efficient and selective, with no contaminating cells from TESE biopsy material400 ul chamber 5 um policarobne filtre ile ayrılmış, 15kda poliacrimide membrana bağlı. 23 C,5 dakika V uygulanmış. DNA hasarı TUNEL ve SCSA il değerlendirilmiş. Anlamlı oranda DNA hasarı az olan sperm ayrımı sağlanabilmiş.