Reactive oxygen species and human spermatozoa: analysis of the cellular mechanisms involved in luminol- and lucigenin-dependent chemiluminescence.

We have shown that human spermatozoa generate and release reactive oxygen species that can be detected by chemiluminescence techniques. Analysis of the cellular mechanisms responsible for this activity suggests that the probe, luminol, undergoes an intracellular dioxygenation reaction mediated by hydrogen peroxide and a sperm peroxidase located within the acrosome. Support for this model included the following observations: (1) the luminol-dependent signal could be suppressed with peroxidase inhibitors, phenylhydrazine and sodium azide; (2) this suppression could be reversed by the addition of an azide-insensitive peroxidase, horse radish peroxidase (HRP); (3) inhibition of intracellular superoxide dismutase (SOD) with potassium cyanide (KCN) suppressed the luminol signal; (4) peroxidase activity could be detected in purified populations of human spermatozoa with 3,3',5,5' tetramethylbenzidine (TMB); (5) this peroxidase was active at the pH prevailing within the acrosomal vesicle; and (6) peroxidase activity and luminol-dependent chemiluminescence were minimal in spermatozoa exhibiting a congenital absence of acrosomes. Human spermatozoa could also generate lucigenin-dependent chemiluminescent signals that could neither be suppressed with peroxidase inhibitors nor enhanced by the addition of peroxidase. However, these signals could be enhanced by suppression of intracellular SOD with KCN or inhibited by exogenous SOD, suggesting that lucigenin was responding to superoxide anion released into the extracellular space. The ability of chemiluminescent techniques to detect and discriminate the production of superoxide and hydrogen peroxide by spermatozoa should facilitate the further analysis of reactive oxygen species as mediators of normal and abnormal human sperm function.     

Functional changes and motility characteristics of Japanese Black bull spermatozoa separated by Percoll

Spermatozoa from two Japanese Black bulls (Bull-ATF and Bull-KTG) were separated by centrifugation at 700 x g for 15min in modified TALP with or without 45-90% Percoll. Control washed spermatozoa and those collected from the bottom of 45 and 90% Percoll fractions were examined for viability and membrane integrity (using Hoechst bis-benzimide 33258 or propidium iodide and 6-carboxyfluorescein diacetate (PI-CFDA)), acrosomal status (using fluorescence isothiocyanate (FITC) conjugated Pisum Sativum agglutinin (PSA) and Peanut agglutinin (PNA), Naphthol Yellow S and Erythrosin B (NE) or triple staining (TS)), capacitation status (using chlortetracycline (CTC)), motility characteristics (using a computer-assisted sperm motion analysis system (CASA)) and for in vitro fertility. Percoll-separated spermatozoa showed greater viability and membrane integrity than controls, as determined by supravital staining. Differences were observed in the results regarding viability and acrosomal status of spermatozoa among sperm staining methods. Bull-ATF, which showed significantly greater in vitro fertility than Bull-KTG (P<0.05), showed a significantly higher rate of CTC-B-pattern (capacitated) spermatozoa (P<0.01) than Bull-KTG. The motility characteristics of control washed spermatozoa and those separated by 45-90% Percoll were analyzed by CASA. More motile and progressively motile spermatozoa were observed in the fraction at the bottom of the 90% Percoll solution than in the 45% Percoll fraction or in controls (P<0.01). Moreover, the spermatozoa of Bull-KTG, which showed lower in vitro fertility than Bull-ATF, did not show significant differences in motility from those of Bull-ATF. These results provided basic information about Japanese Black bull spermatozoa, and suggested that spermatozoa with greater motility and viability can be obtained by Percoll separation than without separation. However, Percoll separation did not enhance their in vitro fertility.     

Origin of reactive oxygen species in human semen: spermatozoa or leucocytes?

Peroxidative damage induced by reactive oxygen species (ROS) has been proposed as one of the major causes of defective sperm function. In previous studies of the production of ROS in semen, the contribution of contaminating leucocytes was not assessed. We determined the levels of ROS in 60 semen samples from men attending our infertility clinic and demonstrated by performing extraction experiments with antibody-coated magnetic beads that, within this unselected population of patients, leucocytes were the major source of ROS in the low-density Percoll fraction. Of the sperm motion parameters examined using computerized semen analysis, beat-cross frequency was the only one significantly affected by the ROS in semen.     

Nuclear maturity and morphology of human spermatozoa selected by Percoll density gradient centrifugation or swim-up procedure

The selection of motile human spermatozoa, from fertile and infertile semen samples was compared by using Percoll density gradient centrifugation or the swim-up procedure. Selected spermatozoa were evaluated according to their motility, % normal forms, nuclear maturity (aniline blue staining, acridine orange staining, ethidium bromide uptake and SDS nuclear decondensation). These methods showed differences between fertile and infertile men. The swim-up procedure, based on motility, resulted in greater proportions of motile spermatozoa and eliminated mainly tail abnormalities. Percoll gradient separation, based on density, selected oval-headed spermatozoa with good motility. Nuclear maturity level was improved by both methods but Percoll gradient separation generally resulted in spermatozoa with better nuclear maturity than those selected by the swim-up procedure.     

High Levels of Cadmium and Lead in Seminal Fluid and Blood of Smoking Men are Associated with High Oxidative Stress and Damage in Infertile Subjects

We measured the levels of malondialdehyde (MDA), protein carbonyls, glutathione S-transferase (GST) and reducte glutathione (GSH) in seminal plasma and spermatozoa from 95 subjects including 50 infertile patients to evaluate the association between oxidative stress and damage and the components of the anti-oxidant defenses in seminal plasma and spermatozoa of infertile subjects and concentrations of cadmium (Cd) and lead (Pb) in the blood and seminal plasma because of tobacco smoke exposure. The reactive oxygen species (ROS) in spermatozoa were also evaluated by luminol (5-amino-2,3-dihydro-1,4-phthalazinedione)-enhanced chemiluminescence assay. The sperm count, motility, and morphology in the smokers infertile group were found to be lower than those in the fertile male group and nonsmokers infertile group (p < 0.001). Concentrations of Cd, Pb, MDA, protein carbonyls, and ROS levels in the smokers infertile group were significantly higher than those in the fertile male and nonsmokers infertile male groups (p < 0.001). However, GSH levels and GST activities were decreased in the smokers infertile male group than those in the fertile male and nonsmokers infertile male groups (p < 0.001). The results indicate that smoking could affect semen quality and oxidative lipid and protein damage in human spermatozoa. From Pearson correlation analysis, positive correlations were demonstrated between the seminal plasma Cd and seminal plasma protein carbonyls and between seminal plasma Pb and spermatozoa ROS levels in smokers of the subfertile group, while there was a significant positive correlation between blood Cd and ROS levels in smokers of the fertile group. There was also a significant negative correlation of the Cd level of the blood and GSH levels of the sperm and seminal plasma. These findings suggest that cigarette smoking enhances the levels of Cd and Pb in seminal plasma and blood and the extent of oxidative damage associated with a decrease in components of the anti-oxidant defenses in the sperm of infertile males.     

Generation of reactive oxygen species, lipid peroxidation, and human sperm function

Recent studies have demonstrated that human spermatozoa are capable of generating reactive oxygen species and that this activity is significantly accelerated in cases of defective sperm function. In view of the pivotal role played by lipid peroxidation in mediating free radical damage to cells, we have examined the relationships between reactive oxygen species production, lipid peroxidation, and the functional competence of human spermatozoa. Using malondialdehyde production in the presence of ferrous ion promoter as an index of lipid peroxidation, we have shown that lipid peroxidation is significantly accelerated in populations of defective spermatozoa exhibiting high levels of reactive oxygen species production or in normal cells stimulated to produce oxygen radicals by the ionophore, A23187. The functional consequences of lipid peroxidation included a dose-dependent reduction in the ability of human spermatozoa to exhibit sperm oocyte-fusion, which could be reversed by the inclusion of a chain-breaking antioxidant, alpha-tocopherol. Low levels of lipid peroxidation also had a slight enhancing effect on the generation of reactive oxygen species in response to ionophore, without influencing the steady-state activity. At higher levels of lipid peroxidation, both the basal level of reactive oxygen species production and the response to A23187 were significantly diminished. In contrast, lipid peroxidation had a highly significant, enhancing effect on the ability of human spermatozoa to bind to both homologous and heterologous zonae pellucidae via mechanisms that could again be reversed by alpha-tocopherol. These results are consistent with a causative role for lipid peroxidation in the etiology of defective sperm function and also suggest a possible physiological role for the reactive oxygen species generated by human spermatozoa in mediating sperm-zona interaction.     

Antioxidant levels in blood and seminal plasma and their impact on sperm parameters in infertile men

Excess reactive oxygen species (ROS) beyond the scavenging capacity of antioxidants leads to DNA damage and oxidation of lipoprotein components at the cellular and subcellular level. The oxidative stress (OS) adversely affects sperm function by altering membrane fluidity, permeability and impairs sperm functional competence. In the present study, the OS status in seminal plasma and blood serum in infertile men and its relationship with spermatozoa parameters have been investigated. Four groups of infertile men viz., oligozoospermic (n = 15), asthenozoospermic (n = 17), teratozoospermic (n = 19), and oligoasthenoteratozoospermic (n = 9), and healthy fertile controls (n = 40) have been analyzed for superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) in seminal plasma and blood serum. Significant correlation between blood serum SOD and sperm count has been observed in patients (p = 0.018) and controls (p = 0.021). Similarly, significant correlation between blood serum GSH and sperm progressive motility in patients (p = 0.036) and controls (p = 0.029) is observed. The low seminal MDA is associated with increase in sperm progressive motility in patients (p = 0.039) and controls (p = 0.028). Positive correlation is found between increased seminal MDA levels and abnormal sperm morphology in both patients and controls (r = 0.523, p = 0.029; r = 0.612, p = 0.034 respectively). Correlations between blood SOD and sperm count and between blood GSH levels and progressive motility suggest that these can be important biochemical markers in assaying the sperm count and motility. A negative correlation of motility with seminal MDA indicates that sperm membrane lipid peroxidation affects the fluidity and thus mobility of sperm axoneme. This affects functional competence of the sperm and acts like a biological safeguard. The results of the present study suggest the prospects of using the blood serum and seminal plasma antioxidants as a valuable tool to evaluate the sperm reproductive capacity and functional competence.     

Relationship between fertilizing ability of frozen human spermatozoa and capacity for heparin binding and nuclear decondensation.

Nuclear decondensation of spermatozoa induced by heparin, reduced glutathione (GSH) or a mixture of heparin and GSH was studied using frozen-thawed human spermatozoa. The percentages of decondensed spermatozoa in controls and after treatment for 60 min with 30 mumol heparin l-1, 5 mmol GSH l-1, or heparin-GSH mixture were 1.5, 22.1, 4.3 and 37.6%, respectively. Most of the decondensed spermatozoa were eliminated by Percoll gradient centrifugation of samples previously treated with heparin or heparin-GSH mixture. However, comparable numbers of motile spermatozoa were recovered in the control and in each treated sample, demonstrating that a major proportion of motile spermatozoa was resistant to heparin (or heparin-GSH) effects on nuclear decondensation of spermatozoa. Fertilization of hamster oocytes was attempted using spermatozoa recovered in the 90% Percoll fraction and resistant to heparin-GSH decondensing mixture. Although insemination used a constant number of motile spermatozoa, fertilization rates were higher after treatments with heparin and GSH alone than in control or heparin-GSH-treated samples. In addition the number of spermatozoa that attached to the oocyte plasma membrane was a sixth or a half for sperm pretreated with heparin-GSH or heparin alone, respectively compared with untreated values. However, there was no evidence for induced acrosomal reaction by heparin and GSH, at least at the concentrations used. Qualitative analyses of heparin-binding sites were performed on untreated spermatozoa recovered in the 90% Percoll fraction by incubating spermatozoa in the presence of heparin covalently linked to albumin and coupled to colloidal gold (5 nm). Among this population of spermatozoa, 40.5% bound heparin-gold and labelling was mainly observed on the sperm head surface (88% of labelled spermatozoa) with (59.5%) or without (28.5%) tail labelling. Only a small proportion (23%) of spermatozoa that attached to the oocyte plasma membrane bound heparin-gold conjugate and only weak labelling was observed on the sperm head. Moreover, the proportion of spermatozoa that bound heparin-gold conjugate decreased (r = -0.77, P less than 0.0001) in relation to increasing concentrations of motile spermatozoa in the sample.(ABSTRACT TRUNCATED AT 400 WORDS)     

The production of reactive oxygen and nitrogen species by skeletal muscle.

Skeletal muscle has been recognized as a potential source for generation of reactive oxygen and nitrogen species for more than 20 years. Initial investigations concentrated on the potential role of mitochondria as a major source for generation of superoxide as a "by-product" of normal oxidative metabolism, but recent studies have identified multiple subcellular sites, where superoxide or nitric oxide are generated in regulated and controlled systems in response to cellular stimuli. Full evaluation of the factors regulating these processes and the functions of the reactive oxygen species generated are important in understanding the redox biology of skeletal muscle.     

Impaired E-cadherin expression in human spermatozoa in a male factor infertility subset signifies E-cadherin-mediated adhesion mechanisms operative in sperm-oolemma interactions

Cadherins comprise a family of calcium-dependent glycoproteins that function in mediating cell-cell adhesion in virtually all solid tissues of multicellular organisms. We have examined the presence of a cadherin on spermatozoon and its possible involvement in sperm-oocyte interaction. Spermatozoa from fertile human subjects showed the presence of E-cadherin on its head domains, detectable only after permeabilization of the surface membranes. On the contrary, spermatozoa from oligozoospermic subjects did not possess E-cadherin on their principal acrosomal and equatorial domains. Immunoprecipitation and Western blot studies also showed the presence of E-cadherin in spermatozoa from fertile males and its absence in oligozoospermic males. Using RT-PCR, we detected E-cadherin message in the round cells of fertile males, which was absent in the cells from oligozoospermic males. The presence of anti-E-cadherin antibody brought about quantitative reduction in the sperm-oocyte binding in vitro. These observations indicate the possibility of the interplay of a cadherin-dependent homophilic and/or heterophilic adhesion interaction between spermatozoa and oocyte during fertilization. The absence of a key adhesion molecule in a human male infertility disorder points towards genetic defects causing failure in gamete interactions.     

Reactive oxygen species in spermatozoa: methods for monitoring and significance for the origins of genetic disease and infertility

Human spermatozoa generate low levels of reactive oxygen species in order to stimulate key events, such as tyrosine phosphorylation, associated with sperm capacitation. However, if the generation of these potentially pernicious oxygen metabolites becomes elevated for any reason, spermatozoa possess a limited capacity to protect themselves from oxidative stress. As a consequence, exposure of human spermatozoa to intrinsically- or extrinsically- generated reactive oxygen intermediates can result in a state of oxidative stress characterized by peroxidative damage to the sperm plasma membrane and DNA damage to the mitochondrial and nuclear genomes. Oxidative stress in the male germ line is associated with poor fertilization rates, impaired embryonic development, high levels of abortion and increased morbidity in the offspring, including childhood cancer. In this review, we consider the possible origins of oxidative damage to human spermatozoa and reflect on the important contribution such stress might make to the origins of genetic disease in our species.     

Effets à court et à long termes de la cure de varicocèle sur les caractéristiques spermatiques

The authors studied the sperm features of 122 patients, before and 3 months, 6 months, 9 months and 12 months after varicocele repair, in order to define the sperm profiles of these patients and to study effects of this treatment on these profiles. Patients with varicocele generally present severe asthenozoospermia. Of the 122 patients studied: ?18% were extreme oligozoospermic, ?26% were severe oligozoospermic, ?18% were moderate oligozoospermic, ?38% were normozoospermic. Varicocele repair does not influence the volume of semen, the vitality of spermatozoa, their survival, their rate of abnormal shapes, or male genital tract markers, but significantly improves sperm counts and mobility, in men with extreme or severe oligozoospermia. This type of treatment is generally indicated in patients with extreme or severe oligoasthenozoospermia in order to obtain a natural pregnancy, or at least to increase the success of medically assisted procreation techniques.     

Zona pellucida binding and zona-induced acrosome reactions in horse spermatozoa: comparisons between fertile and subfertile stallions

Diagnostic tests that probe sperm function are needed to determine the potential etiologies of subfertility and to explore treatments of subfertility in stallions. Using epifluorescence and phase contrast microscopy, a comparison was made between ejaculates from 3 fertile and 3 subfertile stallions in which sperm-zona pellucida binding and acrosomal status were measured. Motile spermatozoa were selected by Percoll gradient centrifugation and were capacitated in vitro using TEST:TALP capacitation medium at 39 degrees C under humidified air containing 5% CO2. Concentration of motile spermatozoa was held constant during co-incubation with oocytes for fertile and subfertile ejaculates. The total number of zona pellucida-bound spermatozoa was higher for fertile stallions than for subfertile stallions (P < 0.05). Similarly, the percentage of acrosome reactions in zona pellucida-bound spermatozoa was higher for the 3 fertile stallions than for the 3 subfertile stallions (P < 0.05). These results indicate that spermatozoa from fertile stallions may interact with female gametes differently from that of subfertile stallions and suggest that sperm functions are measurable and may vary with fertility.     

Cellular basis of defective sperm function and its association with the genesis of reactive oxygen species by human spermatozoa

Addition of the divalent cation ionophore, A23187, to washed populations of human spermatozoa resulted in a sudden burst of production of reactive oxygen species which peaked within 3-5 min. This activity was dependent upon the presence of calcium in the external medium and was unaffected by the mitochondrial inhibitors, oligomycin, antimycin and rotenone. Studies with scavengers of reactive oxygen species revealed that, while reagents directed against singlet oxygen and the hydroxyl radical were without effect, cytochrome C reduced the response to A23187 by about 50%, suggesting that the superoxide anion radical is a major product of the activated human spermatozoon. The clinical implications of these studies stem from the considerable variation observed between individuals in the levels of reactive oxygen species produced by the spermatozoa. This variability was shown to be inversely related to the ability of the spermatozoa to exhibit sperm-oocyte fusion on exposure to A23187; defective samples exhibited a basal level of reactive oxygen species production which was 40 times that observed with normal functional cells.     

Radicaux libres et spermatozoïdes humains: physiologie et physiopathologie

The role of reactive oxygen species in the physiopathology of human sperm function has been emphasized in recent years. Their production in semen has been associated with loss of motility, decreased capacity for spermoocyte fusion and loss of fertility. In semen preparations, there are two major sources of reactive oxygen species: leucocytes and spermatozoa themselve. It has been proposed that reactive oxygen species production by human spermatozoa was dependent upon a membrane-bound NADPH oxidase or a mitochondrial diaphorase. Hydrogen peroxide produced by the dismutation of superoxide anion has been recognized as the most toxic oxidizing species for human spermatozoa. Owing to their high content of polyunsaturated fatty acids, it has been proposed that lipid peroxidation of the sperm plasma membrane is largely responsible for defective sperm function. Reactive oxygen species also affect the sperm axoneme as a result of ATP depletion, inhibit mitochondrial functions, and synthesis of DNA, RNA and proteins, produce cytoskeletal modifications and inhibit sperm-oocyte fusion. Human spermatozoa possess enzymatic defence systems such as superoxide dismutase, glutathion peroxidas/reductase and catalase to counteract the toxic effects induced by reactive oxygen species. Correlations have been reported between their effectiveness and the duration of sperm motility. If the excessive production of reactive oxygen species is detrimental for human spermatozoa, they could also participate in the physiological function of the spermatozoa when present at low concentrations. Indeed, reactive oxygen species have been shown to be involved in the activation of several enzymes. Furthermore, sperm capacitation, acrosome reaction and sperm-zona interaction would be enhanced by reactive oxygen species.     

Gonadotropin response to acute stimulation with LHFSHRH in idiopathic oligospermia. Preliminary results]

Serum FSH and LH levels in basal conditions and after Gn-RH test were investigated in 15 idiopathic oligozoospermic patients. Basal FSH was significantly higher in oligospermic than in normal subjects and a negative relationship was found between basal FSH and sperm count. Basal LH was not different in oligozoospermic and in normal subjects. Both FSH and LH responses to GN-RH were significantly higher in oligozoospermic patients. In idiopathic oligozoospermia the presence of a testicular defect involving both the seminiferous epithelium and Leydig cells is suggested.     

Levels of antioxidant defenses are decreased in bovine spermatozoa after a cycle of freezing and thawing

Growing evidence suggests that the generation of reactive oxygen species (ROS) and their detoxification by antioxidants plays a very important role in fertility. However, the relationship between the level of antioxidants in spermatozoa and the decreased fecundity following a freeze/thaw cycle remains poorly understood. We assessed the activities of antioxidant enzymes such as catalase, glutathione peroxidase (GPx), superoxide dismutase (SOD), and levels of reduced/oxidized glutathione (GSH/GSSG) in bovine semen. Sperm cells were isolated using a Percoll gradient to avoid contamination from seminal plasma, cellular debris, and other cell types. We found that bovine spermatozoa are poorly adapted to metabolize the toxic hydrogen peroxide (H(2)O(2)). Indeed, very low levels of GPx and an absence of catalase were observed. We also studied the effect of freezing and thawing bovine spermatozoa in a egg yolk-Tris-glycerol extender (EYTG). Cryopreservation significantly reduced sperm GSH levels by 78% and SOD activity by 50%. We also investigated whether the decrease in GSH level could be linked to oxidative metabolism and found that a greater reduction in intracellular GSH level occurred when fresh sperm cells were incubated in EYTG for 6 hr at 38.5 degrees C under aerobic conditions than when incubated under restricted oxygen availability. Our results strongly suggest the involvement of an oxidative stress during a freeze/thaw cycle and are consistent with the hypothesis that ROS generated during such a cycle are detrimental to sperm function.     

Identification of cytochrome P450-reductase as the enzyme responsible for NADPH-dependent lucigenin and tetrazolium salt reduction in rat epididymal sperm preparations

Lucigenin-dependent chemiluminescence and WST-1 reduction can be detected following addition of NADPH to many cell types, including rat epididymal sperm suspensions. Although many reports suggest that such a phenomenon is due to reactive oxygen species production, other probes-such as MCLA and luminol-that are capable of detecting reactive oxygen metabolites do not produce a chemiluminescent signal in this model system. Our aim was to purify and identify the enzyme catalyzing the NADPH-dependent lucigenin and WST-1 reduction from rat epididymal spermatozoa preparations. Here, we show the identity of this enzyme as cytochrome P450-reductase. In support of this, a homogenous preparation of this protein was capable of reducing lucigenin and WST-1 in the presence of NADPH. Moreover, COS-7 cells overexpressing cytochrome P450-reductase displayed a 3-fold increase in the aforementioned activity compared with mock-transfected cells. Immunolocalization studies and biochemical analysis suggest that the majority of the NADPH-lucigenin activity is localized to the epithelial cells present within the epididymis. These results emphasize the importance of the direct NADPH-dependent reduction of superoxide-sensitive probes by cytochrome P450-reductase even though this enzyme does not, on its own accord, produce reactive oxygen species.     

Relationship of SNP of H2BFWT gene to male infertility in a Chinese population with idiopathic spermatogenesis impairment

The H2B family, member W, testis specific (H2BFWT) gene encodes a testis specific histone that plays a crucial role in reorganization and remodeling of chromatin and epigenetic regulation during spermatogenesis, suggesting that the gene may be involved in spermatogenesis impairment. To test the speculation, the allele and haplotype frequencies of two single-nucleotide polymorphism loci in this gene, -9C>T and 368A>G, were investigated in 409 infertile patients with idiopathic azoospermia or oligozoospermia and 209 fertile men as controls using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. As the results, the frequencies of -9T (52.8% vs. 41.6%, p = 0.009) and 368G (43.0% vs. 32.5%, p = 0.012) were significantly higher in patients than those in controls; after stratifying patients, the significant higher frequencies were still detected in allele -9T for azoospermia (57.4% vs. 41.6%, p = 0.001) and allele 368G for oligozoospermia (45.4% vs. 32.5%, p = 0.007). The haplotype CA was significantly decreased (22.8% vs. 33.0%, p = 0.006) whereas TG was significantly increased (18.3% vs. 7.2%, p < 0.001) in infertile patients compared with controls. These results indicated that the polymorphism -9C>T and 368A>G in H2BFWT gene are associated with male infertility with idiopathic azoospermia or oligozoospermia, suggesting that H2BFWT gene might be contribute to susceptibility to spermatogenesis impairment in Chinese population.     

严重寡精症ICSI精子供体的DAZ基因拷贝缺失研究

DAZ基因拷贝缺失与人类的生精障碍有关。为了解中国正常生精男性和ICSI中严重寡精症精子供体DAZ基因拷贝缺失的分布, 探讨DAZ基因拷贝数检测在严重生精障碍精子供体遗传缺陷筛查中的意义, 本研究运用多重PCR和PCR-RFLP技术, 对128例严重寡精症ICSI精子供体和287个正常生精男性的DAZ基因缺失进行了研究。发现DAZ1/DAZ2、DAZ3/DAZ4和全部4个拷贝缺失等3种拷贝缺失类型, 其中全部4个拷贝缺失仅见于严重寡精症患者, 频率为11.7%; DAZ1/DAZ2缺失的频率在严重寡精症患者中显著高于正常男性(9.4% vs 2.8%, P = 0.004); 在严重寡精症患者中DAZ基因拷贝完全缺失与DAZ1/DAZ2缺失的总发生率为21.1%。DAZ3/DAZ4缺失的频率在两组人群中无显著差异(7.0% vs 3.8%, P > 0.05)。这些结果提示, DAZ基因全部拷贝缺失是严重寡精症患者生精障碍的常见遗传病因, 而DAZ1/DAZ2缺失则可能是一种高风险因素。鉴于上述DAZ基因缺失在严重生精障碍精子供体中较高的发生率, 在应用ICSI进行辅助生育前, 建议对严重寡精症的精子供体进行DAZ基因全缺失与DAZ1/DAZ2共缺失筛查, 以评估其男性后代患病的风险。