451
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Abstract
OBJECTIVES To examine the retention of sperm cytoplasmic droplets (CD) and DNA denaturation (DD) in semen from fertile and infertile men. METHODS Semen samples were obtained from consecutive nonazoospermic men presenting for infertility evaluation (n = 101) and fertile men presenting for vasectomy (n = 13). The standard semen parameters (sperm concentration, motility, and morphology), sperm DD, and sperm CD were monitored. Sperm DD was evaluated by flow cytometry analysis of acridine orange-treated spermatozoa and expressed as the percentage of spermatozoa demonstrating denatured DNA. RESULTS The mean (+/-SE) percentages of spermatozoa with CD and DD were significantly higher in infertile than in fertile men (sperm CD 15.7% +/- 0.8% versus 4.8% +/- 0.7% and sperm DD 22.0% +/- 1.5% versus 10.8% +/- 1.8%, respectively). Sperm CD and DD were positively correlated (r = 0.59). Also, sperm CD and DD values correlated inversely with the standard semen parameters. CONCLUSIONS Our data demonstrate that the retention of sperm CD correlates positively with sperm DD and that significantly higher sperm DD and CD are found in infertile than in fertile men. These data suggest that the enhanced susceptibility of sperm DNA to denaturation is associated with the abnormal disposal of residual sperm cytoplasm in the testis and/or epididymis.
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Affiliation(s)
- Marc Anthony Fischer
- Division of Urology, Department of Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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452
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Oehninger S. Pathophysiology of oligoasthenoteratozoo-spermia: are we improving in the diagnosis? Reprod Biomed Online 2003; 7:433-9. [PMID: 14656405 DOI: 10.1016/s1472-6483(10)61887-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Male infertility is one of the most common identifiable causes of human reproductive failure. Although considerable progress has been made toward understanding sperm physiology and the biology of gamete interaction, still more work is needed to achieve objectivity and standardization of some of the andrological diagnostic methods used in the clinical setting. More information is needed to definitively establish which tests are more accurate predictors of sperm performance and how they correlate with pregnancy potential following in-vivo and in-vitro interventions. Infertile men can be successfully treated with defined urological and medical therapies or with assisted reproductive technologies. Among the latter, intracytoplasmic sperm injection (ICSI) has become a validated means to overcome multiple sperm deficiencies. However, male infertility remains idiopathic in a large proportion of cases. As a consequence, it is expected that simplified and more cost-efficient therapeutic modalities will be developed as additional basic (cellular-molecular) and pathophysiological/clinical knowledge is gained.
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Affiliation(s)
- Sergio Oehninger
- The Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, 601 Colley Avenue, Norfolk, VA 23507, USA.
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453
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Aitken RJ, Baker MA. Reactive oxygen species generation by human spermatozoa: a continuing enigma. INTERNATIONAL JOURNAL OF ANDROLOGY 2002; 25:191-4. [PMID: 12121567 DOI: 10.1046/j.1365-2605.2002.03521.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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454
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Perera D, Pizzey A, Campbell A, Katz M, Porter J, Petrou M, Irvine DS, Chatterjee R. Sperm DNA damage in potentially fertile homozygous beta-thalassaemia patients with iron overload. Hum Reprod 2002; 17:1820-5. [PMID: 12093845 DOI: 10.1093/humrep/17.7.1820] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND To test the hypothesis that human sperm DNA could sustain iron-induced oxidative damage and reduce its fertilizing ability, we studied patients with homozygous beta-thalassaemia major (HbTh) as a model of iron overload. METHODS Sperm from six thalassaemic patients and five age-matched controls were assessed by the sperm chromatin structure assay (SCSA) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay. Semen parameters, endocrine markers of testicular function, iron profiles and the presence of organ dysfunction were also determined. RESULTS All patients with HbTh were iron overloaded (median ferritin: 2251 microg/l) and had evidence of spontaneous spermatogenesis. Thalassaemic patients had more sperm DNA damage than the controls (P < 0.01). The sperm DNA damage by SCSA and TUNEL were positively correlated (P < 0.05). Sperm motility and TUNEL results were negatively correlated (P < 0.05), while the age of onset of chelation and sperm DNA damage were positively associated with both SCSA (R(2) = 0.80, P = 0.016) and TUNEL data (R(2) = 0.67, P < 0.044). No other biochemical or clinical data were associated with sperm DNA damage. CONCLUSIONS The increase in sperm DNA damage and the negative correlation between sperm motility and DNA damage suggest that iron overload in HbTh predisposes sperm to oxidative injury. This finding has important implications in assisted reproductive procedures such as ICSI where there is increased risk of transmitting defective DNA to the offspring.
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Affiliation(s)
- Doreen Perera
- Department of Obstetrics and Gynaecology, University College Hospital, UCL London, Huntley Street, London WC1E 6AU, UK
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455
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Hammitt DG, Ferrigni RG, Sattler CA, Rebert JA, Singh AP. Development of a new and efficient laboratory method for processing testicular sperm. J Assist Reprod Genet 2002; 19:335-42. [PMID: 12168734 PMCID: PMC3455750 DOI: 10.1023/a:1016010709945] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Testicular biopsy specimens contain large amounts of debris that makes sperm pick-up for ICSI more difficult than with epididymal aspirates. We sought to develop improved processing techniques for testicular sperm extraction (TESE). METHODS Retrievals were with azoospermic male partner scheduled to undergo percutaneous epididymal sperm aspiration (PESA) and TESE. The study group consisted of 9 retrievals with a new TESE technique (TESE-N). The control group was 21 retrievals with PESA and 3 retrievals with a previous TESE technique (TESE-P). RESULTS TESE-N eliminated almost all debris, which made ICSI sperm pick-up more rapid. TESE-N, PESA, and TESE-P fertilization (77, 75, and 72%) and ongoing/delivered pregnancy rates per retrieval (67, 76, and 67%) were similar. CONCLUSIONS Our new technique provides for easy removal of debris from TESE specimens and fertilization and pregnancy rates equal to epididymal sperm's. Eliminating debris from TESE specimens allows for rapid sperm pick-up for ICSI, making the procedure more efficient for embryology staff.
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Affiliation(s)
- Diane G Hammitt
- Department of Gynecology, Mayo Clinic Scottsdale, Arizona 85260, USA.
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456
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Foote RH, Brockett CC, Kaproth MT. Motility and fertility of bull sperm in whole milk extender containing antioxidants. Anim Reprod Sci 2002; 71:13-23. [PMID: 11988368 DOI: 10.1016/s0378-4320(02)00018-0] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bull sperm are exposed to aerobic conditions during processing before freezing, and they have little endogenous antioxidant to protect them against reactive oxygen species that may be present. Seventeen laboratory studies and two field trials were conducted with 174 semen collections from bulls in an artificial breeding cooperative. More than 250 combinations and concentrations of reduced glutathione (GSH), superoxide dismutase (SOD), ascorbic acid, hypotaurine (HPT), 2,2,6,6-tetramethylpeperidine-1-oxyl (Tempo) and 4-hydroxy-2, 2, 6, 6-tetramethylpeperidine (Tempol) were tested by adding these compounds to fresh semen, and to a whole milk (WM) glycerol extender. Semen packaged in straws in the WM extender was frozen with liquid nitrogen. The motility of frozen-thawed sperm during storage at 25 or 5 degrees C after freezing was compared with semen stored without freezing. Antioxidants generally were not beneficial, except the percentage of motile sperm was improved by 6-11% units (P<0.05) when sperm were stored unfrozen or after freezing when 0.5mM of GSH with or without SOD was added. In two field trials, non-return rates were 71.9, 69.5 and 70.9% (P>0.05) with WM containing 0.0, 0.5 and 1.0mM of GSH, respectively, and 74.0 and 73.9% with WM and WM plus 0.5mM of GSH and 100U/ml of SOD (P>0.05). WM contains an abundant supply of casein which is an antioxidant, and additional antioxidants were ineffective in improving motility of sperm immediately after freezing and thawing or in affecting fertility. However, sperm responses were different in egg yolk-Tris extender. Sperm in this egg yolk extender tolerated substantial concentrations of Tempo and Tempol compared with toxic effects in WM (P<0.05). Therefore, optimal combinations of antioxidants tested here may have more useful applications in organizations using an egg yolk-based semen extender.
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Affiliation(s)
- Robert H Foote
- Department of Animal Science, 204 Morrison Hall, Cornell University, Ithaca, NY 14853-4801, USA.
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457
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Moffatt O, Drury S, Tomlinson M, Afnan M, Sakkas D. The apoptotic profile of human cumulus cells changes with patient age and after exposure to sperm but not in relation to oocyte maturity. Fertil Steril 2002; 77:1006-11. [PMID: 12009359 DOI: 10.1016/s0015-0282(02)02951-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine the expression of apoptosis-associated molecules on cumulus cells removed from individual oocytes of different maturity, inseminated oocytes and to investigate the possibility of an age-dependent expression. DESIGN Analysis of apoptosis in cumulus cells isolated from oocytes of different stages of maturity. SETTING Assisted reproductive technology program of the Birmingham Women's Hospital, Birmingham, UK. PATIENT(S) Patients undergoing intracytoplasmic sperm injection or IVF cycles. MAIN OUTCOME MEASURE(S) Percentage of positive cumulus cells when assessed for nuclear DNA damage using the terminal deoxyuridine nucleotide end-labeling assay or stained with antibodies [Fas, Fas ligand, the antiapoptotic protein Bcl-xl, and the RNA-binding protein (TIAR)]. RESULT(S) Cumulus cells collected from mature oocytes showed no significant difference in the percentage of apoptotic markers compared to those recovered from immature oocytes, whereas those from patients >/=38 years differed significantly. When cumulus cells were exposed to sperm the levels of apoptotic markers altered significantly from those not exposed to sperm. CONCLUSION(S) The results show that the cumulus cells of human oocytes are equipped with a mechanism to undergo apoptosis and that patient age and the exposure of cumulus cells to sperm can alter their profiles of apoptotic markers.
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Affiliation(s)
- Odette Moffatt
- Assisted Conception Unit. Birmingham Women's Hospital, Edgbaston, Birmingham, United Kingdom
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458
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Aguilar-Mahecha A, Hales BF, Robaire B. Chronic cyclophosphamide treatment alters the expression of stress response genes in rat male germ cells. Biol Reprod 2002; 66:1024-32. [PMID: 11906922 DOI: 10.1095/biolreprod66.4.1024] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Increases in the survival rate of men treated with chemotherapeutic drugs and their desire to have children precipitate concerns about the effects of these drugs on germ cells. Azoospermia, oligospermia, and infertility are common outcomes resulting from treatment with cyclophosphamide, an alkylating agent. Exposure of male rats to cyclophosphamide results in dose-dependent and time-specific adverse effects on progeny outcome. Elucidation of the effects of chronic low-dose cyclophosphamide treatment on the expression of stress response genes in male germ cells may provide insight into the mechanisms underlying such adverse effects. Male rats were gavaged with saline or cyclophosphamide (6 mg/kg) for 4-5 wk; pachytene spermatocytes, round spermatids, and elongating spermatids were isolated; RNA was extracted and probed on cDNA arrays containing 216 cDNAs. After saline treatment, 125 stress response genes were expressed in pachytene spermatocytes (57% of genes studied), 122 in round spermatids (56%), and 83 in elongating spermatids (38%). Cyclophosphamide treatment reduced the number of genes detected in all germ cell types. The predominant effect of chronic cyclophosphamide exposure was to decrease the expression level of genes in pachytene spermatocytes (34% of genes studied), round spermatids (29%), and elongating spermatids (4%). In elongating spermatids only, drug treatment increased the expression of 8% of the genes studied. The expression profiles of genes involved in DNA repair, posttranslational modification, and antioxidant defense in male germ cells were altered by chronic cyclophosphamide treatment. We hypothesize that the effects of cyclophosphamide exposure on germ cell gene expression during spermatogenesis may have adverse consequences on male fertility and progeny outcome.
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Affiliation(s)
- Adriana Aguilar-Mahecha
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec, Canada H3G 1Y6
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459
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Kaneko T, Iuchi Y, Kobayashi T, Fujii T, Saito H, Kurachi H, Fujii J. The expression of glutathione reductase in the male reproductive system of rats supports the enzymatic basis of glutathione function in spermatogenesis. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:1570-8. [PMID: 11874473 DOI: 10.1046/j.1432-1033.2002.02809.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glutathione reductase (GR) recycles oxidized glutathione (GSSG) by converting it to the reduced form (GSH) using an NADPH as the electron source. The function of GR in the male genital tract of the rat was examined by measuring its enzymatic activity and examining the gene expression and localization of the protein. Levels of GR activity, the protein, and the corresponding mRNA were the highest in epididymis among testes, vas deferens, seminal vesicle, and prostate gland. The localization of GR, as evidenced by immunohistochemical techniques, reveals that it exists at high levels in the epithelia of the genital tract. In testis, GR is mainly localized in Sertoli cells. The enzymatic activity and protein expression of GR in primary cultured testicular cells confirmed its predominant expression in Sertoli cells. Intracellular GSH levels, expressed as mol per mg protein, was higher in spermatogenic cells than in Sertoli cells. As a result of these findings, the effects of buthionine sulfoximine (BSO), an inhibitor for GSH synthesis, and 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU), an inhibitor for GR, on cultured testicular cells were examined. Sertoli cells were prone to die as the result of BCNU, but not BSO treatment, although intracellular levels of GSH declined more severely with BSO treatment. Spermatogenic cells were less sensitive to these agents than Sertoli cells, which indicates that the contribution of these enzymes is less significant in spermatogenic cells. The results herein suggest that the GR system in Sertoli cells is involved in the supplementation of GSH to spermatogenic cells in which high levels of cysteine are required for protamine synthesis. In turn, the genital tract, the epithelia of which are rich in GR, functions in an antioxidative manner to protect sulfhydryl groups and unsaturated fatty acids in spermatozoa from oxidation during the maturation process and storage.
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Affiliation(s)
- Tomoko Kaneko
- Department of Biochemistry, Yamagata University School of Medicine, Yamagata, Japan
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460
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Anzar M, He L, Buhr MM, Kroetsch TG, Pauls KP. Sperm apoptosis in fresh and cryopreserved bull semen detected by flow cytometry and its relationship with fertility. Biol Reprod 2002; 66:354-60. [PMID: 11804948 DOI: 10.1095/biolreprod66.2.354] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The present study was conducted to detect sperm apoptosis in fresh and frozen semen and to determine its relationship with bull fertility. Three ejaculates were collected from five breeding bulls with different fertility levels and were cryopreserved using standard methods. Two flow cytometric methods were employed to measure apoptosis: an assay for phosphatidylserine (PS) translocation across the plasma membranes using fluorescein-labeled Annexin V and propidium iodide (PI), and an assay for nicked DNA using bromodeoxyuridine (BrdU), terminal deoxynucleotidyl transferase, and fluorescein-labeled anti-BrdU monoclonal antibody. Both assays showed that fresh sperm contained 10%-20% apoptotic sperm. Significant differences in the percentage of apoptotic sperm were observed among the bulls. Cryopreservation induced translocation of PS to the outer leaflet of the plasma membrane and caused most of the necrotic cells in fresh sperm to disintegrate. Bull fertility was significantly related to the percentage of necrotic or viable sperm in fresh semen as detected by the Annexin V/PI assay, to the number of apoptotic sperm in fresh semen as detected by the TUNEL assay, and to the level of chromatin or DNA condensation as detected by PI staining. The present study suggests that the presence of apoptotic spermatozoa in fresh semen could be one of the reasons for poor fertility in breeding bulls.
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Affiliation(s)
- Muhammad Anzar
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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461
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Check JH, Check ML, Katsoff D. Prognosis for sperm fertilizability: analysis of different variables in men. ARCHIVES OF ANDROLOGY 2002; 48:73-83. [PMID: 11789686 DOI: 10.1080/014850102753385233] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
An overview of various sperm tests is presented. The standard semen analysis obtained by most clinicians evaluating infertility usually consists of sperm concentration, percent motility, quality of motility, and sperm morphology. Unfortunately, unless the motile density is extremely low, the count and motility are not good prognosticators of fertility potential. Values above the norm for normal fertile couples unfortunately cannot reliably predict normal fertility potential. It is important to find sperm tests that are easy to perform, are relatively inexpensive, and provide an accurate prognosis. Strict morphology was hoped to be such a tool with initial optimism that it was far superior to standard morphology. Unfortunately, this test also failed to be the ideal inexpensive prognostic test after further evaluation. One test that is inexpensive and highly correlates with fertilizability is the presence of antisperm antibodies since their presence frequently does not alter count, motility, or morphology. This test should be performed as part of the routine semen analysis. Other tests highly correlate with the achievement of pregnancy and are simple and inexpensive to perform, but, interestingly, do not correlate with fertilizability. These include the hypoosmotic swelling test (HOST) and the sperm stress test. Abnormalities in these tests imply a different abnormality of sperm that leads to conception failure and that is the transfer of a toxic factor from the sperm to oocyte to embryo that prevents the embryo from implanting. Certainly, the simple, inexpensive HOST should be performed routinely. Other tests of sperm function, e.g., sperm penetration assay, sperm zona pellucida binding assay, and acrosome reaction, have their definite place in the evaluation of the infertile male. However, because they are expensive and difficulty to perform they lend themselves to certain specific circumstances but not to routine testing.
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Affiliation(s)
- J H Check
- The University of Medicine/Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden, USA
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462
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Medeiros CMO, Forell F, Oliveira ATD, Rodrigues JL. Current status of sperm cryopreservation: why isn't it better? Theriogenology 2002; 57:327-44. [PMID: 11775978 DOI: 10.1016/s0093-691x(01)00674-4] [Citation(s) in RCA: 239] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cryopreservation extends the availability of sperm for fertilization; however, the fertilizing potential of the frozen-thawed sperm is compromised because of alterations in the structure and physiology of the sperm cell. These alterations, characteristics of sperm capacitation, are present in the motile population and decrease sperm life-span, ability to interact with female tract, and fertilizing ability. The etiology of such alterations may represent a combination of factors, such as inherited fragility of the sperm cell to withstand the cryopreservation process and the semen dilution. Although the former is difficult to address, approaches that make-up for the dilution of seminal fluid may be sought. The aim of this work is to review aspects of sperm cryopreservation paralleled by events of capacitation and evaluate the possible roles of sperm membrane cholesterol, reactive oxygen species, and seminal plasma as mediators of cryopreservation effects on sperm function.
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Affiliation(s)
- C M O Medeiros
- Laboratório de Embriologia e Biotécnicas de Reprodução, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970 Brazil.
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463
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Tesarik J, Greco E, Mendoza C. Assisted reproduction with in-vitro-cultured testicular spermatozoa in cases of severe germ cell apoptosis: a pilot study. Hum Reprod 2001; 16:2640-5. [PMID: 11726588 DOI: 10.1093/humrep/16.12.2640] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Apoptosis-related cell damage is known to compromise success rates of assisted reproduction with ejaculated spermatozoa. This study was undertaken to determine whether the frequency of apoptosis-related cell damage and reproductive performance of testicular spermatozoa from men with non-obstructive azoospermia can be improved by in-vitro culture. METHODS Testicular tissue samples were cultured for 2 days in the presence of 50 IU/l FSH and 1 micromol/l testosterone. The frequency of spermatozoa showing DNA strand breakage and plasma membrane phosphatidylserine externalization was compared in before-culture and after-culture samples. The after-culture samples were used in assisted reproduction attempts. RESULTS In a group of 11 azoospermic patients with at least two previous intracytoplasmic sperm injection (ICSI) failures, the incidence of DNA strand breakage was high in living testicular spermatozoa from before-culture samples, but significantly lower in after-culture samples (96 versus 30%, P < 0.001). The same applied to the incidence of phosphatidylserine externalization in the motile sperm subpopulation from the before-culture and after-culture samples (83 versus 6%, P < 0.001). Seven ongoing clinical pregnancies (six with fresh embryos and one with cryopreserved embryos) were established. CONCLUSIONS Severe testicular sperm apoptosis may become a new indication for testicular tissue in-vitro culture before ICSI.
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464
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Taylor CT. Antioxidants and reactive oxygen species in human fertility. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2001; 10:189-198. [PMID: 21782576 DOI: 10.1016/s1382-6689(01)00099-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The cellular components of the human reproductive system are as vulnerable as other cells to the potential detrimental effects of reactive oxygen species (ROS). Antioxidant protection is thus required, though not yet fully characterized, at sites of gametogenesis, fertilization and implantation. Spermatozoa are highly susceptible to oxidative damage due to the high content of polyunsaturated fatty acids within their plasma membrane and such damage may underlie certain aspects of male infertility. However, oral antioxidant therapy with, for example, Vitamin E or glutathione has to date only achieved limited success in treatment programmes. Infertility treatments involve in vitro manipulation of gametes and embryos, ranging from simple spermatozoa preparation techniques to several days culture, exposing cells to increased oxygen levels and potential oxidative stress compared with in vivo. A considerable body of data has demonstrated the benefits for animal embryo culture and human sperm preparation of antioxidant supplementation as well as the removal of sources of ROS such as leucocytes, although data supporting supplementation for human embryo culture are limited. However, the use of exogenous superoxide dismutase may improve embryo development to the blastocyst stage. Evidence is accumulating for a role for ROS in signalling events mediating both sperm capacitation and luteal function. Potential also exists for ROS (including nitric oxide) to fulfill as yet unidentified roles in modulation signalling, gene expression and/or apoptotic events during fertilization, embryo development and implantation. Increasing knowledge of the mechanisms whereby ROS and endogenous antioxidant systems influence reproductive processes can assist to optimise the application of exogenous antioxidants to fertility treatment.
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Affiliation(s)
- C T Taylor
- The Fertility Centre, Priory Hospital, Priory Road, Edgbaston, Birmingham, B5 7UG, UK
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465
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Ollero M, Gil-Guzman E, Lopez MC, Sharma RK, Agarwal A, Larson K, Evenson D, Thomas AJ, Alvarez JG. Characterization of subsets of human spermatozoa at different stages of maturation: implications in the diagnosis and treatment of male infertility. Hum Reprod 2001; 16:1912-21. [PMID: 11527898 DOI: 10.1093/humrep/16.9.1912] [Citation(s) in RCA: 221] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Reactive oxygen species (ROS)-induced damage of membrane phospholipids and DNA in human spermatozoa has been implicated in the pathogenesis of male infertility. In this study, variations in ROS production, DNA structure (as measured by the sperm chromatin structure assay) and lipid composition, were studied in human spermatozoa at different stages of maturation. METHODS Sperm subsets were isolated by discontinuous density gradient centrifugation of semen samples obtained from healthy donors and from infertility patients. RESULTS DNA damage and ROS production were highest in immature spermatozoa with cytoplasmic retention and abnormal head morphology, and lowest in mature spermatozoa. Docosahexaenoic acid and sterol content were highest in immature germ cells and immature spermatozoa, and lowest in mature spermatozoa. The relative proportion of ROS-producing immature spermatozoa in the sample was directly correlated with DNA damage in mature spermatozoa, and inversely correlated with the recovery of motile spermatozoa. There was no correlation between DNA damage and sperm morphology in mature spermatozoa. CONCLUSIONS The high levels of ROS production and DNA damage observed in immature spermatozoa may be indicative of derangements in the regulation of spermiogenesis. DNA damage in mature spermatozoa may be the result of oxidative damage by ROS-producing immature spermatozoa during sperm migration from the seminiferous tubules to the epididymis.
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Affiliation(s)
- M Ollero
- Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
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466
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Younglai EV, Holt D, Brown P, Jurisicova A, Casper RF. Sperm swim-up techniques and DNA fragmentation. Hum Reprod 2001; 16:1950-3. [PMID: 11527903 DOI: 10.1093/humrep/16.9.1950] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Swim-up techniques for sperm separation may have detrimental effects on sperm DNA. We wished to determine whether the normal swim-up method with centrifugation used in our laboratory, which involves a centrifugation step, was harmful to sperm compared with swim-up without centrifugation. METHODS Semen samples were obtained from patients undergoing IVF or andrology assessment. An aliquot was removed for fixation and subsequent DNA fragmentation determination. The remaining sample was divided into two equal parts, which were subjected to swim-up either with (normal swim-up) or without (direct-swim-up) centrifugation. Semen analysis was performed both before and after swim-up. DNA fragmentation, in spermatozoa previously fixed in 4% paraformaldehyde, was assessed by the terminal transferase-mediated DNA end-labelling procedure (TUNEL). The percentage of spermatozoa with DNA damage after each swim-up technique was compared with that in the original semen sample. RESULTS DNA damage was <5% in most samples. No significant change in DNA fragmentation was observed between the two swim-up procedures, although the 'normal' swim-up sample had significantly less DNA fragmentation than the pre-swim-up sample. CONCLUSIONS We conclude that our normal swim-up technique caused no more DNA damage to spermatozoa from normal semen samples than a direct swim-up technique that involved no centrifugation step.
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Affiliation(s)
- E V Younglai
- Division of Reproductive Sciences, The Toronto General Hospital, The Samuel Lunenfeld Research Institute, University of Toronto, Toronto, Ontario, Canada.
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467
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Haines GA, Hendry JH, Daniel CP, Morris ID. Increased levels of comet-detected spermatozoa DNA damage following in vivo isotopic- or X-irradiation of spermatogonia. Mutat Res 2001; 495:21-32. [PMID: 11448639 DOI: 10.1016/s1383-5718(01)00181-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To investigate whether DNA damage arising in spermatogenic germ cells can be detected in resultant sperm, we have irradiated murine testis and collected spermatozoa from the vas deferens 45 days later. These cells were derived from spermatogonia present at the time of irradiation. Two forms of irradiation were used, external X-rays (4Gy) and internal auger electrons from contamination of the male mouse with the isotope Indium-114m (1.85MBq), which was localised in the testis. Both forms of irradiation produced a profound fall in vas deferens sperm count and testis weight, Indium-114m being more effective. Using the neutral Comet assay for double strand break detection, significant increases in sperm comet tail length and moment were observed. The levels of damage were similar for both treatments. Care had to be taken during the assay to distinguish between sperm and somatic cells as the proportion of the latter increased after irradiation. We conclude that the comet assay can detect DNA damage in spermatozoa after the in vivo exposure of male germ cells to a known testicular genotoxic agent. The assay may be useful for the assessment of sperm DNA damage (double stranded) associated with male infertility and post-fertilization developmental abnormalities in the offspring.
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Affiliation(s)
- G A Haines
- School of Biological Sciences, University of Manchester, Manchester, UK
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468
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Bencic DC, Ingermann RL, Cloud JG. Does CO2 enhance short-term storage success of Chinook salmon (Oncorhynchus tshawytscha) milt? Theriogenology 2001; 56:157-66. [PMID: 11467511 DOI: 10.1016/s0093-691x(01)00551-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Successful short-term storage of salmonid milt depends on numerous factors, including temperature, fluid volume, and gaseous environment, with storage at low temperatures under an atmosphere of 100% O2 being the most common method. Salmonid sperm maintained in a storage environment with elevated carbon dioxide (CO2) levels, such as the approximately 4% CO2 in exhaled air, are not motile when activated. While these modest levels of CO2 inhibit sperm motility, the effect is reversible within hours after exposure to a CO2-free oxygenated environment. Therefore, the effect of CO2 (as a component gas in the storage environment) on chinook salmon (Oncorhynchus tshawytscha) sperm motility and viability was examined. The hypothesis of the current investigation was that CO2-exposure with subsequent CO2 removal would be beneficial during short-term chinook salmon milt storage. Milt samples were collected from mature (adult) and precocious (jack) male chinook salmon and stored under various CO2 and O2 levels at 3 to 4 degrees C for up to 14 days. Milt samples were then removed from the incubation environments and maintained under CO2-free humidified air with continuous mixing for 4 h at 10 degrees C before analysis of motility. The resultant motility of samples incubated under 3.5% or less CO2 was not different than controls during the 14 d incubation period; motility of samples stored under higher CO2 tensions were significantly lower. The motility of samples incubated under 3.5% CO2 reached the maximum recovered motility after 2 h exposure to CO2-free humidified air, while the motility of sperm incubated under 13.4% CO2 levels recovered no motility even after 6 h exposure to CO2-free humidified air. The motility of samples incubated under normoxia was significantly greater than that of samples incubated under hyperoxia (approximately 90% O2) at both 7 and 14 d, regardless of the CO2 level. Sperm viability was relatively unaltered by any of the incubation conditions examined. The results of this investigation suggest that there is no apparent advantage to storage of chinook salmon sperm in the presence of CO2 and that storage under hyperoxia negatively affects sperm function compared to storage under normoxia.
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Affiliation(s)
- D C Bencic
- Department of Cell and Developmental Biology, The University of North Carolina at Chapel Hill, 27599-7090, USA
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469
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Jeong BS, Yang X. Cysteine, glutathione, and Percoll treatments improve porcine oocyte maturation and fertilization in vitro. Mol Reprod Dev 2001; 59:330-5. [PMID: 11424219 DOI: 10.1002/mrd.1038] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Several factors have been examined to improve in vitro fertilization and development of porcine oocytes. Cysteine is known to be beneficial for oocyte maturation and male pronuclear formation in pigs and glutathione is known to help prevent membrane disruption of sperm in other species, including human. It has also been reported that the presence of cumulus cells influences the outcome of in vitro fertilization in cattle. The objectives of the present study were to investigate the effects of several factors involved in porcine in vitro maturation (IVM) and fertilization (IVF) procedures on oocyte embryogenic competence. The following factors were examined: the effects of different concentrations (0, 0.285, 0.57, 1.14, 2.28 microM) and exposure duration (22 and 44 hr) of cysteine during IVM, glutathione inclusion and of cumulus presence during IVF, and the use of gradient Percoll (45%/90%) during sperm preparation. The presence of cysteine in maturation medium improved blastocyst development significantly regardless of the duration of exposure when compared to the control (11--16% vs. 4%, P < 0.01). However, no dose-responsive effect was observed at the concentrations tested. The use of gradient Percoll during sperm preparation significantly improved cleavage (85% vs. 57%, P < 0.01) and blastocyst development (24% vs. 6%, P < 0.01) over conventional sperm preparation. Significant improvement was also achieved by the addition of glutathione to Percoll gradient (30% vs. 20%, P < 0.05). In conclusion, cysteine and glutathione as well as Percoll and cumulus were beneficial to embryogenic competence of porcine oocytes in this study. Mol. Reprod. Dev. 59:330-335, 2001.
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Affiliation(s)
- B S Jeong
- Department of Animal Science, University of Connecticut, Storrs, Connecticut 06269, USA
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470
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Bombail V, Aw D, Gordon E, Batty J. Application of the comet and micronucleus assays to butterfish (Pholis gunnellus) erythrocytes from the Firth of Forth, Scotland. CHEMOSPHERE 2001; 44:383-392. [PMID: 11459143 DOI: 10.1016/s0045-6535(00)00300-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This report describes an investigation of genotoxic effects in an inter-tidal fish species sampled along a pollution gradient in the Firth of Forth, Scotland, UK. The comet assay is an electrophoretic technique for measuring DNA breakage in nuclei from individual cells and has only recently been applied to field investigations of genotoxicity. The measurement of nuclear anomalies (NA), such as the presence of micronuclei (MN) and 'lobes', has been successfully utilised in many field studies of genotoxic effects of contaminated sediments. These two techniques were applied to nucleated red blood cells (RBC) from the butterfish, Pholis gunnellus. The comet assay was adapted and validated for use in this species. Fish were sampled from the inner Firth of Forth, which has a legacy of industrial contamination and the outer Firth of Forth which is comparatively clean. The analysis of DNA strand breakage using this technique did not reveal any significant differences between animals sampled from inner and outer zones of the Firth. In contrast, MN and NA frequencies were elevated in the inner polluted zone of the Firth compared to the outer zone. This study suggests: (1) there are genotoxic effects associated with contaminants in the inner Firth of Forth, and (2) the comet assay may not be a suitable genotoxicity biomarker in fish.
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Affiliation(s)
- V Bombail
- School of Life Sciences, Napier University, Edinburgh, Scotland, UK
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471
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Affiliation(s)
- S Oehninger
- Division of Reproductive Endocrinology, Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, 23507, Norfolk, VA, USA
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472
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Karbownik M, Gitto E, Lewiñski A, Reiter RJ. Relative efficacies of indole antioxidants in reducing autoxidation and iron-induced lipid peroxidation in hamster testes. J Cell Biochem 2001; 81:693-9. [PMID: 11329624 DOI: 10.1002/jcb.1100] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Increased iron stores are associated with free radical generation and carcinogenesis. Lipid peroxidation is involved in DNA damage, thus indirectly participating in the early steps of tumor initiation. Melatonin and structurally related indoles are effective in protecting against oxidative stress. The aim of the study was to compare the relative efficacies of melatonin, N-acetylserotonin (NAS), indole-3-propionic acid (IPA), and 5-hydroxy-indole-3-acetic acid (5HIAA) in altering basal and iron-induced lipid peroxidation in homogenates of hamster testes. To determine the effect of the indoles on the autoxidation of lipids, homogenates were incubated in the presence of each agent in concentrations of 0.0, 0.01, 0.05, 0.1, 0.25, 0.5, 0.75, 1.0, 2.0, 2.5, or 5.0 mM. To study their effects on induced lipid peroxidation, homogenates were incubated with FeSO(4) (30 microM + H(2)O(2) (0.1 mM) + each of the indoles in the same concentrations as above. The degree of lipid peroxidation was expressed as concentrations of malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) per mg protein. The indoles decreased both basal and iron-related lipid peroxidation in a concentration-dependent manner. Melatonin reduced basal MDA + 4-HDA levels when used at the concentrations of 0.25 mM or higher, and prevented iron-induced lipid peroxidation at concentrations of 1.0, 2.0, 2.5, or 5.0 mM. The lowest effective concentrations of NAS required to lower basal and iron-related lipid peroxidation were 0.05 mM and 0.25 mM, respectively. IPA, only when used in the highest concentrations of 2.5 mM or 5 mM inhibited basal lipid peroxidation levels and it was ineffective on the levels of MDA + 4-HDA due to iron damage. 5HIAA reduced basal lipid peroxidation when used at concentrations of 0.25 mM or higher, and it prevented iron-induced lipid peroxidation only at the highest applied concentration (5 mM). In conclusion, melatonin and related indoles at pharmacological concentrations protect against both the autoxidation of lipids as well as induced peroxidation of lipids in testes. In doing so, these agents would be expected to reduce testicular cancer that is initiated by products of lipid peroxidation.
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Affiliation(s)
- M Karbownik
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
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473
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Krzyzosiak J, Molan P, McGowan L, Vishwanath R. Effect of sperm number and oxygenation state of the storage media on in vitro fertility of bovine sperm stored at ambient temperature. Theriogenology 2001; 55:1401-15. [PMID: 11354702 DOI: 10.1016/s0093-691x(01)00490-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The effects of storage time and the oxygenation state of the storage medium on motility, viability, and in vitro fertility of stored diluted sperm were investigated. Oocytes collected from abattoir material were matured and fertilized in vitro on defined days with sperm stored for up to 11 days in a citrate-based commercial diluent. The proportions of oocytes fertilized and developing to the blastocyst stage were used to assess the quality of the stored semen. In vitro fertility of sperm declined with storage time. There was no significant effect of the oxygenation state of the medium on in vitro fertility of stored sperm. Increased sperm-to-oocyte ratios resulted in a significant elevation of the proportion of oocytes fertilized on day 0 of storage and the proportion of fertilized oocytes developing to the blastocyst stage on days 0 and 3 of storage, suggesting some form of sperm competition or egg selection of sperm based on the ability of sperm to induce normal development.
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Affiliation(s)
- J Krzyzosiak
- Livestock Improvement Corporation, Hamilton, New Zealand
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474
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Zini A, Bielecki R, Phang D, Zenzes MT. Correlations between two markers of sperm DNA integrity, DNA denaturation and DNA fragmentation, in fertile and infertile men. Fertil Steril 2001; 75:674-7. [PMID: 11287017 DOI: 10.1016/s0015-0282(00)01796-9] [Citation(s) in RCA: 269] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To evaluate two different assays of human sperm DNA integrity, DNA denaturation (DD) and DNA fragmentation (DF), and to correlate these with standard semen parameters. DESIGN Prospective, observational study. SETTING University infertility clinic. PATIENT(S) Forty consecutive semen samples from 33 nonazoospermic men presenting for infertility evaluation and 7 fertile men presenting for vasectomy. INTERVENTION(S) Assessment of sperm concentration, motility, morphology, DD and DF. MAIN OUTCOME MEASURE(S) Sperm DD and DF in fertile and infertile men. RESULT(S) The mean (+/-SE) rates of DD and DF were significantly higher in infertile subjects compared to fertile controls, respectively: 25.4 +/- 3.0 vs. 10.2 +/- 2.3 (P=.028) and 27.6 +/- 2.5 vs. 13.3 +/- 2.5% (P=.016). DF and DD correlated strongly (r = 0.71, P<.0001). Also, DD and DF correlated negatively with standard semen parameters (concentration, motility, and morphology), the strongest correlation being with sperm motility. CONCLUSION(S) The strong correlation between sperm DD and DF, and the higher levels of sperm DNA damage in infertile compared with fertile men, indicate that male infertility is associated with poor sperm DNA integrity. Although infertile men may father children with assisted conception, fertilization with DNA-damaged spermatozoa may increase the risk of genetic disease in the offspring.
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Affiliation(s)
- A Zini
- Division of Urology, Department of Surgery, University of Toronto, Ontario, Toronto, Canada.
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475
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476
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Abstract
OBJECTIVES To compare the effects of density-gradient centrifugation and swim-up technique on sperm DNA integrity. METHODS Semen samples (n = 22) were obtained from consecutive nonazoospermic men presenting for infertility evaluation. Individual samples were divided into three aliquots (whole semen, density-gradient centrifugation, and swim-up) for subsequent analysis of sperm motility and DNA integrity. Sperm DNA integrity was evaluated by flow cytometry analysis of acridine orange-treated spermatozoa and expressed as the percentage of spermatozoa demonstrating denatured DNA. RESULTS Mean sperm motility (+/-SEM) improved significantly after processing with two-layer density-gradient and swim-up compared with whole semen (65.6% +/- 4.0% and 73.0% +/- 3.0% versus 52.0% +/- 3.6%, respectively, P <0.005), with no significant difference in motility between Percoll-treated and swim-up-treated spermatozoa. In contrast, the percentage of spermatozoa with denatured DNA was reduced significantly in swim-up-treated but not in Percoll-treated spermatozoa compared with whole semen (4.8% +/- 1. 2% and 13.6% +/- 3.6% versus 10.1% +/- 2.3%, respectively, P <0. 0001). CONCLUSIONS Although density-gradient centrifugation is comparable to swim-up technique in recovering spermatozoa with enhanced motility, spermatozoa recovered after swim-up possess higher DNA integrity. These data urge us to reexamine our current sperm processing techniques in order to minimize sperm DNA damage.
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Affiliation(s)
- A Zini
- Division of Urology, Department of Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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477
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L’irradiation des spermatozoïdes au Laser HeNe à faible énergie chez la souris et chez l’homme. ACTA ACUST UNITED AC 2000. [DOI: 10.1007/bf03034498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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478
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Kemal Duru N, Morshedi M, Oehninger S. Effects of hydrogen peroxide on DNA and plasma membrane integrity of human spermatozoa. Fertil Steril 2000; 74:1200-7. [PMID: 11119751 DOI: 10.1016/s0015-0282(00)01591-0] [Citation(s) in RCA: 205] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To evaluate the effects of oxidative stress on DNA and plasma membrane integrity of human spermatozoa. DESIGN Prospective cohort study. SETTING University-based, tertiary-care infertility center. PATIENT(S) Men (n = 10) undergoing infertility investigation. INTERVENTION(S) Purified populations of sperm with high motility were separated using Percoll density gradients. Then, spermatozoa were incubated with 0, 10, 100, and 200 microM hydrogen peroxide (H(2)O(2)) under capacitating conditions. MAIN OUTCOME MEASURE(S) Motion parameters were assessed by computer analysis. Genomic integrity was examined by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) assay. Plasma membrane integrity was evaluated by the annexin V-binding assay, a measure of phosphatidylserine translocation. RESULT(S) Under basal conditions, there was a significant and negative relationship between sperm motility and the percentages of sperm with DNA fragmentation and membrane translocation of phosphatidylserine. After a 2-h incubation, there was a significant, dose-dependent effect of H(2)O(2) on motion parameters (decrease) and DNA fragmentation (increase). The percentage of annexin V(-) live (normal) cells declined significantly as the level of oxidative stress increased. Although the percentages of annexin V(+) live cells (sperm depicting translocation of phosphatidylserine) and necrotic cells increased at the highest H(2)O(2) levels, these changes were not significant. CONCLUSION(S) In vitro sperm incubation with H(2)O(2) induces DNA fragmentation in a dose-dependent fashion. The sublethal effects of oxidative stress on motion parameters were not significantly associated with membrane translocation of phosphatidylserine.
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Affiliation(s)
- N Kemal Duru
- Department of Obstetrics and Gynecology, GATA School of Medicine, Ankara, Turkey
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479
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Banerjee S, Lamond S, McMahon A, Campbell S, Nargund G. Does blastocyst culture eliminate paternal chromosomal defects and select good embryos?: inheritance of an abnormal paternal genome following ICSI. Hum Reprod 2000; 15:2455-9. [PMID: 11098009 DOI: 10.1093/humrep/15.12.2455] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Following intracytoplasmic sperm injection (ICSI), approximately 60-70% of oocytes are fertilized and of these embryos, approximately 45% withstand in-vitro culture conditions to produce healthy blastocysts. The efficiency of implantation of 2-4-cell embryos selected at the pronuclear stage and that of blastocysts are comparable. However, prolonged selection of embryos in vitro (4-5 days), has been proposed to eliminate chromosomal abnormalities, more specifically those inherited by defective spermatozoa. This hypothesis is based upon the assumption that the paternal genetic contribution is indispensable for blastocyst development. Here we examine this hypothesis and suggest that phenotypic manifestation of paternal genomic abnormalities might not occur prior to implantation. In addition to the parent-of-origin effect during embryogenesis, blastocyst transfer may not prevent the inheritance of genetic defects involving 'male factor' loci.
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Affiliation(s)
- S Banerjee
- Centre for Reproductive Medicine, Department of Obstetrics & Gynaecology, St. George's Hospital Medical School, Cranmer Terrace, University of London, London SW17 ORE, UK
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480
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Flesch FM, Gadella BM. Dynamics of the mammalian sperm plasma membrane in the process of fertilization. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1469:197-235. [PMID: 11063883 DOI: 10.1016/s0304-4157(00)00018-6] [Citation(s) in RCA: 350] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sexual reproduction requires the fusion of sperm cell and oocyte during fertilization to produce the diploid zygote. In mammals complex changes in the plasma membrane of the sperm cell are involved in this process. Sperm cells have unusual membranes compared to those of somatic cells. After leaving the testes, sperm cells cease plasma membrane lipid and protein synthesis, and vesicle mediated transport. Biophysical studies reveal that lipids and proteins are organized into lateral regions of the sperm head surface. A delicate reorientation and modification of plasma membrane molecules take place in the female tract when sperm cells are activated by so-called capacitation factors. These surface changes enable the sperm cell to bind to the extra cellular matrix of the egg (zona pellucida, ZP). The ZP primes the sperm cell to initiate the acrosome reaction, which is an exocytotic process that makes available the enzymatic machinery required for sperm penetration through the ZP. After complete penetration the sperm cell meets the plasma membrane of the egg cell (oolemma). A specific set of molecules is involved in a disintegrin-integrin type of anchoring of the two gametes which is completed by fusion of the two gamete plasma membranes. The fertilized egg is activated and zygote formation preludes the development of a new living organism. In this review we focus on the involvement of processes that occur at the sperm plasma membrane in the sequence of events that lead to successful fertilization. For this purpose, dynamics in adhesive and fusion properties, molecular composition and architecture of the sperm plasma membrane, as well as membrane derived signalling are reviewed.
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Affiliation(s)
- F M Flesch
- Department of Biochemistry and Cell Biology, and Department of Farm Animal Health, Graduate School of Animal Health and Institute for Biomembranes, Utrecht University, Yalelaan 2, 3584 CM, Utrecht, The Netherlands
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481
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Tielemans E, van Kooij R, Looman C, Burdorf A, te Velde E, Heederik D. Paternal occupational exposures and embryo implantation rates after IVF. Fertil Steril 2000; 74:690-5. [PMID: 11020508 DOI: 10.1016/s0015-0282(00)00720-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate any influence of paternal occupational exposures on implantation rates after IVF. DESIGN Cohort study of couples who sought IVF treatment. SETTING University Hospital Utrecht, The Netherlands. PATIENT(S) The study population was composed of 726 couples pursuing IVF treatment. INTERVENTION(S) Only the earliest IVF treatment cycle with ET was selected for the analysis. All couples filled in a generic questionnaire on lifestyle factors and details about their occupation. In addition, more detailed exposure information was obtained for pesticides with use of job-specific questionnaires and a subsequent telephone interview. MAIN OUTCOME MEASURE(S) The implantation rate was defined as the number of gestational sacs seen with ultrasound at 6-7 weeks of pregnancy, divided by the number of embryos replaced. RESULT(S) A significantly reduced implantation rate was seen among couples with male partners working in occupations with presumably high levels of organic solvent exposure. Conversely, paternal pesticide exposure was significantly associated with an increased implantation rate. Paternal exposures to metal dust or fumes and welding fumes were not related to the probability of implantation. CONCLUSION(S) The findings suggested that paternal organic solvent exposure decreased the implantation rate among couples undergoing IVF-ET treatment.
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Affiliation(s)
- E Tielemans
- Environmental and Occupational Health Group, University of Utrecht, Utrecht, The Netherlands
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482
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Zini A, Nam RK, Mak V, Phang D, Jarvi K. Influence of initial semen quality on the integrity of human sperm DNA following semen processing. Fertil Steril 2000; 74:824-7. [PMID: 11020532 DOI: 10.1016/s0015-0282(00)01495-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To examine and compare the effects of density-gradient centrifugation on the integrity of sperm DNA from the semen of both fertile and infertile men. DESIGN Prospective, observational study. SETTING University infertility clinic. PATIENTS Forty-four nonazoospermic, infertile men and nine fertile controls. INTERVENTIONS Semen samples were processed by density-gradient centrifugation. Sperm motility and sperm chromatin structure (evaluated by flow cytometry analysis of acridine orange-treated spermatozoa) were monitored before and after semen was processed. MAIN OUTCOME MEASURES Sperm motility and DNA integrity. RESULTS Following density-gradient centrifugation, mean sperm motility (+/-SEM) improved significantly compared to whole semen in samples from fertile and infertile men, respectively (71 +/- 6 vs. 49 +/- 7% and 56 +/- 3 vs. 44 +/- 3%, P<0.05). However, the percentage of sperm with denatured DNA increased compared to whole semen after processing of samples from infertile (25 +/- 3 vs. 15 +/- 2%, P<0. 01) but not fertile men (9 +/- 3 vs. 8 +/- 2%, P>0.05). CONCLUSIONS Our data indicate that the potential detrimental effect of density-gradient centrifugation on sperm DNA integrity is related to the initial semen quality. These data urge us to examine our current sperm-processing techniques to minimize sperm DNA damage.
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Affiliation(s)
- A Zini
- Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
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483
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Baker HW. Management of male infertility. BAILLIERE'S BEST PRACTICE & RESEARCH. CLINICAL ENDOCRINOLOGY & METABOLISM 2000; 14:409-22. [PMID: 11097783 DOI: 10.1053/beem.2000.0088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The causes of infertility are known in a small proportion of patients, and only a few are treatable: gonadotrophin deficiency, genital tract obstruction, sperm autoimmunity, coital dysfunction and reversible effects of toxins, drugs or intercurrent illnesses. Other patients have reduced sperm quality or function that may be associated with previous testicular damage, varicocele or non-specific genital tract inflammation. No treatments have been proved to increase semen quality and fertility in this group; intracytoplasmic sperm injection is the most appropriate management if a natural pregnancy is unlikely to occur. Apart from the transmission of genetic and chromosomal disorders and a small increase in the number of sex chromosomal aneuploidies associated with severe spermatogenic defects, the risk of serious adverse effects in intracytoplasmic sperm injection offspring is low. The pathogenetic mechanisms of the most common forms of defective sperm production are unknown, which prevents the logical development of effective treatment.
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Affiliation(s)
- H W Baker
- University of Melbourne Department of Obstetrics and Gynaecology, The Royal Women's Hospital, Victoria, Carlton, Australia
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484
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Barroso G, Morshedi M, Oehninger S. Analysis of DNA fragmentation, plasma membrane translocation of phosphatidylserine and oxidative stress in human spermatozoa. Hum Reprod 2000; 15:1338-44. [PMID: 10831565 DOI: 10.1093/humrep/15.6.1338] [Citation(s) in RCA: 290] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
UNLABELLED The objectives of this cross-sectional observational study were: (i) to detect DNA damage and plasma membrane translocation of phosphatidylserine in purified sperm populations of high and low motility, and (ii) to analyse their relationship with the endogenous generation of reactive oxygen species. Ejaculates from infertile men were examined following gradient centrifugation. The main outcome measures were: sperm motion parameters (assessed with a computer analyser), generation of reactive oxygen species (measured by chemiluminescence), DNA damage (detected by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling and monoclonal antibody labelling of single-stranded DNA) and translocation of membrane phosphatidylserine (examined with annexin V staining). DNA fragmentation and membrane translocation of phosphatidyl-serine were observed in the fractions with low and high sperm motility in all patients. The fractions with low sperm motility had significantly higher proportion of cells with DNA damage and production of reactive oxygen species than the fractions with high sperm motility (P < 0.005). DNA fragmentation was significantly and positively correlated with the generation of reactive oxygen species (r = 0.42; P = 0.02). IN CONCLUSION (i) spermatozoa from infertile men display translocation of membrane phosphatidylserine as diagnosed by annexin V positive staining; (ii) DNA damage (fragmentation and presence of single-stranded DNA) can be detected in ejaculated spermatozoa from infertile men in fractions with low and high sperm motility, and (iii) there is a relationship between DNA damage and oxidative stress.
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Affiliation(s)
- G Barroso
- The Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA 23507, USA
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485
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Sergerie M, Ouhilal S, Bissonnette F, Brodeur J, Bleau G. Lack of association between smoking and DNA fragmentation in the spermatozoa of normal men. Hum Reprod 2000; 15:1314-21. [PMID: 10831562 DOI: 10.1093/humrep/15.6.1314] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Male factor infertility patients can have anomalies in their sperm nuclei, displaying high levels of loosely packaged chromatin and damaged DNA. The primary objectives of this study were to compare the extent of DNA fragmentation in the spermatozoa of healthy light and heavy smokers versus non-smokers, and to investigate its correlation with concentrations of the smoking markers cotinine and cadmium. A secondary objective was to compare the concentrations of blood cadmium and serum cotinine with corresponding concentrations in seminal plasma. Ninety-seven healthy male volunteers were divided into three groups: non-smokers, light and heavy smokers. There was no difference between the three groups with respect to age, number of ejaculations per week, serum testosterone concentration, and parameters of semen analysis. The percentages of DNA fragmentation in spermatozoa were not statistically different in the heavy smokers (12.11%), light smokers (11.66%) and non-smokers (20.41%). Serum and seminal plasma concentrations of cotinine were significantly higher in heavy smokers compared with the other groups (P < 0.0001). Median values for blood cadmium concentration were higher in heavy smokers (4.50 microg/l) than in light smokers (0.20 microg/l) and non-smokers (0.20 microg/l) (P < 0.001). Cadmium concentration in seminal plasma was significantly higher in heavy smokers (0.20 microg/l) than in light smokers (0.10 microg/l) and non-smokers (0. 10 microg/l) (P < 0.05). In summary, our results indicate no association between smoking and DNA fragmentation in the spermatozoa of healthy men.
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Affiliation(s)
- M Sergerie
- Andrology Laboratory, Centre hospitalier de l'Université de Montréal (CHUM) - Hôpital Saint-Luc, Québec, Canada
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486
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Shen H, Ong C. Detection of oxidative DNA damage in human sperm and its association with sperm function and male infertility. Free Radic Biol Med 2000; 28:529-36. [PMID: 10719234 DOI: 10.1016/s0891-5849(99)00234-8] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The expanding research interest in the last two decades on reactive oxygen species (ROS), oxidative stress, and male infertility has led to the development of various techniques for evaluating oxidative DNA damage in human spermatozoa. Measurement of 8-hydroxydeoxyguanosine (8-OHdG) offers a specific and quantitative biomarker on the extent of oxidative DNA damage caused by ROS in human sperm. The close correlations of 8-OHdG level with male fertility, sperm function and routine seminal parameters indicate the potential diagnostic value of this technique in clinical applications. On the other hand, single cell gel electrophoresis (SCGE or comet assay) and terminal deoxynucleotidyl transferase (TdT) mediated dUTP nick end labeling (TUNEL) assay have also been demonstrated to be sensitive, and reliable methods for measuring DNA strand breaks in human spermatozoa. As certain technical limitations were inherent in each of these tests, it is believed that a combination of these assays will offer more comprehensive information for a better understanding of oxidative DNA damage and its biological significance in sperm function and male infertility.
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Affiliation(s)
- H Shen
- Department of Community, National University of Singapore, 16 Medical Drive, Singapore, Singapore
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487
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Sutovsky P, Schatten G. Paternal contributions to the mammalian zygote: fertilization after sperm-egg fusion. INTERNATIONAL REVIEW OF CYTOLOGY 1999; 195:1-65. [PMID: 10603574 DOI: 10.1016/s0074-7696(08)62703-5] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammalian fertilization has traditionally been regarded as a simple blending of two gametes, during which the haploid genome of the fertilizing spermatozoon constitutes the primary paternal contribution to the resulting embryo. In contrast to this view, new research provides evidence of important cytoplasmic contributions made by the fertilizing spermatozoon to the zygotic makeup, to the organization of preimplantation development, and even reproductive success of new forms of assisted fertilization. The central role of the sperm-contributed centriole in the reconstitution of zygotic centrosome has been established in most mammalian species and is put in contrast with strictly maternal centrosomal inheritance in rodents. The complementary reduction or multiplication of sperm and oocyte organelles during gametogenesis, exemplified by the differences in the biogenesis of centrosome in sperm and oocytes, represents an intriguing mechanism for avoiding their redundancy during early embryogenesis. New studies on perinuclear theca of sperm revealed its importance for both spermatogenesis and fertilization. Remodeling of the sperm chromatin into a male pronucleus is guided by oocyte-produced, reducing peptide glutathione and a number of molecules required for the reconstitution of the functional nuclear envelope and nuclear skeleton. Although some of the sperm structures are transformed into zygotic components, the elimination of others is vital to early stages of embryonic development. Sperm mitochondria, carrying potentially harmful paternal mtDNA, appear to be eliminated by a ubiquitin-dependent mechanism. Other accessory structures of the sperm axoneme, including fibrous sheath, microtubule doublets, outer dense fibers, and the striated columns of connecting piece, are discarded in an orderly fashion. The new methods of assisted fertilization, represented by intracytoplasmic sperm injection and round spermatid injection, bypass multiple steps of natural fertilization by introducing an intact spermatozoon or spermatogenic cell into oocyte cytoplasm. Consequently, the carryover of sperm accessory structures that would normally be eliminated before or during the entry of sperm into oocyte cytoplasm persist therein and may interfere with early embryonic development, thus decreasing the success rate of assisted fertilization and possibly causing severe embryonic anomalies. Similarly, foreign organelles, proteins, messenger RNAs, and mitochondrial DNAs, which may have a profound impact on the embryonic development, are propagated by the nuclear transfer of embryonic blastomeres and somatic cell nuclei. This aspect of assisted fertilization is yet to be explored by a focused effort.
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Affiliation(s)
- P Sutovsky
- Department of Obstetrics and Gynecology, Oregon Health Science University, USA
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488
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Affiliation(s)
- D M De Kretser
- Institute of Reproduction and Development, Monash University, Clayton, Victoria, Australia.
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489
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Zini A, Mak V, Phang D, Jarvi K. Potential adverse effect of semen processing on human sperm deoxyribonucleic acid integrity. Fertil Steril 1999; 72:496-9. [PMID: 10519622 DOI: 10.1016/s0015-0282(99)00295-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To examine the effect of standard Percoll density-gradient centrifugation on human sperm DNA denaturation. DESIGN Prospective, observational study. SETTING University-based infertility clinic. PATIENT(S) Twenty-five nonazoospermic men. INTERVENTION(S) Semen samples (n = 25) were obtained from consecutively seen nonazoospermic men presenting for infertility evaluation. Samples were processed by two-layer and four-layer Percoll density gradients. Sperm motility and sperm chromatin structure (evaluated by flow cytometry analysis of acridine orange-treated spermatozoa) were monitored before and after semen processing. Sperm chromatin integrity was expressed as the percentage of spermatozoa that demonstrated denatured DNA. MAIN OUTCOME MEASURE(S) Sperm motility and DNA integrity. RESULT(S) Mean sperm motility improved significantly after processing with two-layer and four-layer Percoll gradients compared with whole semen (54% and 57% motility versus 44% motility, respectively). In contrast, the percentage of sperm with denatured DNA increased after processing with two-layer and four-layer Percoll gradients compared with whole semen (34% and 32% versus 18%, respectively). CONCLUSION(S) Our data demonstrate that the improvement seen in sperm motility after Percoll processing is not associated with a similar improvement in sperm DNA integrity. These data suggest that we reexamine current sperm processing techniques to minimize sperm DNA damage and the potential transmission of genetic mutations in assisted reproductive cycles.
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Affiliation(s)
- A Zini
- Department of Surgery, Mount Sinai Hospital, University of Toronto, Ontario, Canada.
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490
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Abstract
DNA damage induced by either light exposure or oxidative stress likely contributes to the compromised development in vitro of cultured preimplantation embryos. Using the comet assay, which entails microgel electrophoresis that can readily detect single-strand breaks in DNA, a significant increase in DNA damage was detected in individual one-cell hamster embryos that were treated with either ultraviolet light or hydrogen peroxide. In addition, an increase in DNA damage also was observed following exposure of one-cell embryos to visible light. When the embryos were placed in drops of culture medium that were covered with mineral oil and the dishes then placed in a portable incubator containing 5% CO(2) in air at 37 degrees C, visible and UV light irradiation for 30 min still induced extensive DNA damage when compared to control embryos that were kept in the dark. In contrast, infrared irradiation did not induce an increase in DNA damage. DNA damage also was measured in individual one- and two-cell stage embryos developed in vivo or in vitro. The extent of DNA damage in the cultured embryos was significantly greater than in embryos that developed in vivo. These results highlight the usefulness of the comet assay to assess DNA damage in individual preimplantation embryos and how the assay can be used to monitor culture conditions in vitro.
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Affiliation(s)
- M Takahashi
- Department of Animal Reproduction, National Institute of Animal Industry, Ibaraki, Japan.
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