Sperm DNA damage and its impact on male reproductive health: a critical review for clinicians,reproductive professionals and researchers

Introduction: Sperm DNA damage is the major molecular cause of male infertility, which has a negative effect on reproductive outcomes in couples. Sperm DNA damage originates either during production/maturation or transport of spermatozoa through male genital tract. Though several assays have been used to assess the sperm chromatin integrity and sperm DNA fragmentation (SDF), routine application of SDF testing in semen analysis is generally not reinforced by professional societies. SDF testing is now emerging as a valuable tool and recent clinical practice guidelines (CPG) published by the Society for Translational Medicine recommends SDF testing in various clinical scenarios.

Areas covered: This review discusses the origin and factors contributing to sperm DNA damage, the molecular changes, especially proteomic alterations caused due to SDF, risk factors associated with SDF, methods used to analyze SDF, clinical implications of SDF, and CPG recommendations for SDF testing.

Expert opinion: Recent clinical practice recommendations suggest the potential role of SDF testing in specific clinical scenarios. This would expand the horizon of SDF testing globally as a prognostic and diagnostic tool in various male infertility scenarios and their treatment management.     

HPV感染对男性精子活力及精子DNA完整性的影响

目的通过检测人乳头瘤病毒(HPV)感染的精液中精子活力及精子DNA完整性,探讨HPV感染对精液参数及精子DNA完整性的影响,进一步完善精液质量评估,为男性不育症患者,尤其是弱精子症者的治疗及辅助生殖技术助孕前的检查提供新的依据。方法采用PCR-膜杂交法及染色质扩散实验法检测330例因不育就诊的男性患者精液中HPV感染率、感染亚型、精子活力及精子DNA完整性。根据精液中HPV的感染情况分为HPV感染组和HPV未感染组。分别比较HPV感染组和未感染组间精子活力及精子DNA完整性的差异性。结果 HPV感染组精子活力及精子DNA完整性无明显差异。结论 HPV感染精液对精子活力及精子DNA完整性无明显影响。     

精子DNA完整性对男性生育力的补充预测价值

目的探究精子DNA完整性检测相对传统的精液常规在男性生育力评价中的辅助预估价值。 方法采集收集2017年4月至10月共1076例不育男性精液标本,男性患者来源于安徽医科大学第一附属医院妇产科,每份标本分成2份,分别行精液常规及精子DNA完整性检测,根据精子DNA碎片指数（DFI）分为精子DNA完整性良好组（DFI≥30%）、完整性一般组（15%6/ml）及少精症（<15×10⁶/ml）,按照精子前向活动率分为正常（≥32%）及弱精子症（<32%）,采用χ²检验分析不同精子DNA完整性组之间的年龄、浓度和前向活动率的差异,采用Pearson相关分析分析患者年龄、精子浓度及前向活动率分别与精子DFI的相关性。 结果不同精子DNA完整性组间,精子浓度正常与少精症水平差异具有统计学意义（χ²=96.82,P<0.001）、活力正常与弱精子症水平差异均具有统计学意义（χ²=2.06,P<0.001）。年龄与DFI成正相关（r=0.154,P<0.001）,精子浓度及前向活动率与DFI成负相关（r=-0.231,P<0.001;r=-0.564,P<0.001）。 结论精子DFI与精子浓度及活动率呈负相关,与年龄呈正相关,精子DNA完整性检测一定程度上可以弥补精液常规参数分析在评价男性生育能力上的不足,具有重要参考价值。     

精子DNA碎片率与精子核蛋白不成熟度检测在体外受精治疗中的应用研究

目的探讨精子DNA碎片率及精子核蛋白不成熟度检测在体外受精(IVF)治疗中的应用价值。方法选择2015年3月至2016年2月于本院接受IVF治疗的不育症患者102例,进行精液常规分析、精子核蛋白不成熟度及精子DNA碎片率检测,分析精子核蛋白不成熟度和精子DNA碎片率与精子质量分析参数、IVF受精率及优胚率等的相关性。结果精子DNA碎片率与IVF优胚率、精子活力呈负相关(P0.05),与IVF受精率无相关性(P0.05);精子核蛋白不成熟度与IVF优胚率、IVF受精率无相关性(P0.05),与精子浓度呈负相关(P0.05)。结论精子DNA碎片率与IVF优胚率密切相关,对不育症患者IVF治疗结局具有重要的预测价值。     

Analysis of age-associated alternation of SCSA sperm DNA fragmentation index and semen characteristics of 1790 subfertile males in China

BackgroundIt has been identified that incidence of infertility was about 20% among couples worldwide, about 50% caused by male elements. However, conventional semen laboratory detections could not handle clinical needs, which led to more comprehensive parameters for male fertility evaluation. We aimed to investigate the clinical relationship of age‐linked changes and the sperm chromatin structure assay (SCSA) sperm DNA fragmentation index (DFI), and routine semen characteristics among subfertile Chinese males.Methods1790 clinical semen specimens were enrolled from February 2018 to October 2019. Clinical and laboratory data including routine semen analyses, sperm DFI, and sperm morphology were collected and showed age‐related alterations in semen parameters.ResultsOur results, displayed an increase in sperm DFI with age, were demonstrated in three age‐groups, particularly within the ≥35‐year cohort. There were positive and inverse correlations of sperm DFI with abnormal semen characteristics and with normal morphological parameters, respectively. Furthermore, age, sperm morphology, concentration, and progressive motility, immotile sperm percentage, semen volume, sperm survival, and high acridine orange DNA stainability (indicating immature forms) were found to be independent risk factors affecting sperm DNA integrity. Likewise, men aged ≥35 years had a higher sperm DFI than did normozoospermic men in the overall cohort. Routine semen characteristics, sperm DFI, and morphology tended to alter with age.ConclusionsThe SCSA sperm DFI showed the greatest clinical application in the assessment of male fertility in this study, which should help infertility clinics decide on reproductive options for the treatment of older infertile couples.     

Ureaplasma urealyticum induces polymorphonuclear elastase to change semen properties and reduce sperm motility: a prospective observational study

ObjectiveTo elucidate the mechanism underlying how Ureaplasma urealyticum (UU) affects sperm quality and identify a therapeutic target.MethodsIn this prospective observational study, the differences in and relationships among semen volume, pH, viscosity, liquefaction time, sperm concentration, sperm motility [progressive motility (PR)], and seminal polymorphonuclear (PMN) elastase were analyzed in 198 normal semen samples (control group) and 198 UU-infected semen samples (observation group). The UU-infected samples were treated and the above parameters were compared between the two groups.ResultsThe semen volume, viscosity, liquefaction time, and seminal PMN elastase were significantly higher in the observation than control group, but the pH and PR were significantly lower. In the observation group, the pH and PR were significantly higher after than before treatment, whereas the semen volume, PMN elastase, viscosity, and liquefaction time were lower. UU was closely related to semen volume, pH, viscosity, liquefaction time, sperm motility (PR), and PMN elastase. PMN elastase had significant negative effects on semen pH and sperm motility (PR) but positive effects on viscosity and liquefaction time.ConclusionUU might induce PMN elastase to increase the liquefaction time and viscosity of semen, eventually decreasing PR. PMN elastase might be a therapeutic target of UU.     

精索静脉曲张显微手术后抗精子抗体水平与精子质量相关性分析

目的:探讨精索静脉曲张(VC)患者行显微精索静脉结扎术前后抗精子抗体(AsAb)水平与精子质量的相关性。方法:选择2015年1月至2017年12月行经外环口显微精索静脉结扎术的精索静脉曲张患者67例为病例组,同期同年龄层次育前检查未发现精索静脉曲张者67例为对照组。测定记录病例组手术前、术后(3、6、12个月)及对照组的AsAb阳性率、精液量、精子浓度、精子活动率、向前运动精子率以及精子畸形率,分析各项检测指标变化情况。结果:对照组与病例组术前AsAb阳性率、精子质量5项指标差异均有统计学意义(P0.05)。病例组术后3个月AsAb阳性率与术前差异无统计学意义,术后6、12个月AsAb阳性率均降低,与术前差异有统计学意义(P0.05)。病例组手术后各时间点及对照组精液量均无明显变化。病例组术后精子浓度、精子活动率、向前运动精子率、精子畸形率4项精子质量指标均较术前明显改善,差异有统计学意义(P0.05)。病例组术后12个月精子浓度、精子活动率均较术后6个月、3个月进一步改善,差异有统计学意义(P0.05);病例组术后6个月与术后3个月精子浓度、精子活动率差异无统计学意义。病例组术后各时间点精子畸形率差异无统计学意义。病例组术后12个月、6个月向前运动精子率较术后3个月进一步改善,差异有统计学意义(P0.05);术后12个月与术后6个月向前运动精子率差异无统计学意义。Pearson相关性分析显示,手术前后AsAb阳性率降低与精子浓度、精子活动率改善明显负相关(P0.05)。结论:显微精索静脉结扎术后患者AsAb阳性率明显降低,精子浓度、精子活动率、向前运动精子率及精子畸形率改善明显,且随时间延长,AsAb水平的降低程度与精子浓度、精子活动率改善明显相关,有助于术后疗效的评估。     

精索静脉曲张不育患者各项精液分析指标的特征及其临床价值

目的通过比较精索静脉曲张不育患者与健康婚育检查人士各项精液分析指标水平,探讨精索静脉曲张不育患者各项精液分析指标的特征,并分析精子DNA碎片指数(DFI)与其他精液分析指标的相关性,以及各项指标联合检测在精索静脉曲张不育中的诊断效能。方法将该院2019年经B超确诊为精索静脉曲张,并同时进行精子DNA完整性检查、精液常规参数分析和精子形态分析的107例不育患者纳入精索静脉曲张组,选择同期60例健康婚育检查人士纳入健康对照组。检测并比较两组研究对象精子DFI、高DNA可染性(HDS)、精子浓度、前向运动精子(PR)、正常形态精子百分比(PNS)、畸形精子指数(TZI)、精子畸形指数(SDI),分析精子DFI与其他精液分析指标的相关性,绘制受试者工作特征(ROC)曲线,判断联合检测在精索静脉曲张不育患者中的诊断效能。结果两组精子DFI、HDS、精子浓度、PR、PNS、TZI、SDI比较,差异均有统计学意义(P<0.05)。精子DFI与HDS、TZI、SDI呈正相关(r=0.530、0.454、0.306,P<0.05),与PR、PNS呈负相关(r=—0.559、—0.245,P<0.05),与精子浓度无明显相关性(r=—0.112,P>0.05)。多因素Logistic回归分析显示,精子DFI与HDS是精索静脉曲张不育的独立危险因素[精子DFI(OR=1.179,95%CI:1.094~1.271,P<0.05)、HDS(OR=1.150,95%CI:1.029~1.286,P<0.05)]。ROC曲线分析显示,各项指标联合检测ROC曲线下面积(AUC)为0.871(95%CI:0.819~0.924,P<0.05),灵敏度为71.0%,特异度为95.0%,阳性预测值为95.0%,阴性预测值为65.5%,约登指数为0.660,诊断效能均优于单独检测。结论精索静脉曲张不育患者精子DNA完整性、常规精液分析结果与健康人有差异,精子DFI与部分精液分析指标存在相关性,精子DFI与其他精液常规分析参数联合检测能为临床筛查和治疗精索静脉曲张不育提供更好的依据。     

男性不育患者精子DFI与其他精液参数的关系

目的通过研究精子DNA碎片指数(DFI)与其他精液参数的相关性,探讨精子DFI在诊断和治疗男性不育中的临床应用价值。方法收集2019年1月至2020年1月在该院生殖中心就诊的959例男性不育患者的精液标本,通过计算机辅助分析系统进行精液常规检测,运用Diff-quik染色法对精液进行染色处理后再作形态学分析,采用精子染色质扩散试验检测精子DFI,根据精子DFI值分组,Ⅰ组精子DFI<30%,Ⅱ组精子DFI≥30%,并对精子DFI与其他精液参数的相关性进行分析。结果Ⅰ组有754例;Ⅱ组有205例。Ⅰ组的精子存活率、前向运动精子百分率(PR)、非前向运动精子百分率(NP)和正常形态精子百分率明显高于Ⅱ组,差异有统计学意义(P<0.05)。Ⅰ组患者的年龄、不动精子百分率(IM)明显低于Ⅱ组,差异有统计学意义(P<0.05)。精子DFI与精子存活率、PR、NP、正常形态精子百分率呈负相关(r=-0.409、-0.402、-0.198、-0.216,P<0.05),而与患者年龄和IM呈正相关(r=0.181、0.402,P<0.05)。结论精子DFI与多项精液参数相关,因此精子DFI检测应与精液常规检测及精子形态学分析相结合,为临床评估男性不育患者的生育力提供可靠且准确的评价指标。     

男性不育症患者精子DNA完整性与精液分析参数相关性研究

目的 探讨男性不育症患者精子DNA完整性与精液参数间的相关性.方法 已有生育男性健康者50例(对照组);男性不育症患者100例(不育组),根据精子常规参数检测结果分为参数正常不育组及参数异常不育组.采用计算机辅助精液分析系统分析精液常规和运动参数,采用末端脱氧核苷酸转移酶介导的dUTP末端标记法检测精子DNA碎片化指数(DFI).结果 参数正常不育组和参数异常男性不育组精子DFI均高于对照组(P＜0.05),参数异常不育组精子DFI高于参数正常不育组(P＜0.05);不育组精子DFI与精子密度、正常形态率、活动率、存活率、a级和b级精子活力及精子运动参数(直线速度、曲线速度、平均路径速度和侧摆幅度)呈不同程度负相关(P＜0.05),与c级和d级精子活力呈正相关(P＜0.05),与精子直线性、前向性、摆动性和鞭打频率无相关性(P>0.05).结论 精子DFI是可用于评估精液质量和男性生育能力的理想指标.     

Lack of an Association Between Sperm Head Abnormality and DNA Damage by Alkaline Comet Assay

Sperm DNA damage affects sperm function, compromising reproductive outcome in both natural and assisted reproduction. The present study addresses the existing ambiguity between sperm morphology and DNA damage, by use of comet assay/single cell gel electrophoresis. Using comet assay as an end point, sperm DNA fragmentation in a total of 17 control and infertile subjects presenting to the infertility clinic of Kasturba Medical College has been investigated. Percent tail DNA, tail length and olive tail moment were selected as a measure to compare the extent of DNA damage between the groups. No significant difference was observed between the control group with morphologically normal sperm and experimental group with abnormal sperm morphology with respect to head DNA, tail DNA, Olive tail moment or tail length by alkaline comet assay. The comet assay failed to demonstrate any positive association between sperm morphology and DNA damage. In view of accumulating evidence on the importance of sperm DNA integrity in fertilization and embryogenesis, refined techniques allowing sperm selection with intact sperm DNA or with minimal DNA damage for clinical use should be sought.     

Association between sperm quality, oxidative stress, and seminal antioxidant activity

Objectives

To determine seminal antioxidant capacity, oxidative stress markers, and their association with semen quality as oxidative stress is considered to be a major etiological factor in male infertility.

Subjects and methods

Semen samples were obtained from 138 men and categorized on the basis of sperm count, motility, and morphology. Seminal oxidative and antioxidant markers are as follows: lipid peroxidation (LPO), protein carbonyls (PC), superoxide dismutase (SOD), catalase (CAT), thiols, and ascorbic acid were determined.

Results

Sperm count significantly correlated positively with progressive sperm motility and normal morphology. Sperm count and normal morphology showed significant negative correlation with LPO and PC. Sperm count and progressive motility showed significant positive relationship with SOD. The SOD, CAT, and thiols positively whereas LPO and PC negatively associated with elevated sperm count.

Conclusion

Insufficient antioxidant enzymes and increased oxidative stress may attribute to the risk of declining semen quality and hence protective role for antioxidant enzymes against the oxidative damage cannot be ruled out.     

精子碎片指数与精子形态的关系研究

目的：探讨精子DNA碎片指数（DNA fragmentation index, DFI）与精子形态学之间的相关性。方法：回顾性分析3 068例男性患者的精液检查结果,将精子DFI分为<15%、15%~30%、>30%共3组,再根据精子形态学检查结果,按照正常形态精子所占比例<4%、4%~10%、>10%将精子分为3组,分析精子不同形态学分组与精子DFI分组间的关系。结果：不同精子DFI分组的正常形态、头部畸形、混合畸形百分比差异无统计学意义（P均>0.05）;不同的精子正常形态率分组间的精子DFI差异无统计学意义（P均>0.05）,用Spearson相关性分析精子DFI与精子形态之间的相关性,结果发现两者间无相关性。结论：本研究发现精子DFI与精子形态学之间没有相关性。     

腹腔镜精索静脉高位结扎术对单侧精索静脉曲张伴不育患者精液参数的影响研究

目的分析腹腔镜精索静脉高位结扎术对单侧精索静脉曲张(VC)伴不育患者精液参数的影响。方法选取2014年3月至2016年3月该院收治的单侧VC伴不育患者56例,均行腹腔镜精索静脉高位结扎术。观察并对比术前及术后3个月乳酸脱氢酶同工酶X(LDH-X)在精子及精浆中的含量、精子碎片率(DFI)及其他精子参数。结果腹腔镜精索静脉高位结扎术前精浆与全精子LDH-X的比值、DFI及精浆LDH-X明显高于术后,术前精子LDH-X低于术后,差异均有统计学意义(P0.05);腹腔镜精索静脉高位结扎术前患者精子含量、精子活动率、精子存活率、前向运动精子百分率低于术后,差异有统计学意义(P0.05)。结论单侧VC伴不育患精液的质量、LDH-X的含量和DFI可以通过腹腔镜精索静脉高位结扎术得到积极的改善。     

不育男性生殖道沙眼衣原体感染对精子核DNA碎片化指数的影响

目的探讨不育男性生殖道沙眼衣原体感染对精子核DNA碎片化指数的影响。方法选择2017年1月至2017年5月在成都市锦江区妇幼保健院生殖医学中心(成都西囡妇科医院)门诊初诊的117例生殖道沙眼衣原体感染的不育男性(感染组)和92例体检正常的男性(对照组),对两组的精液常规参数及精子核DNA完整性(以精子核DNA碎片化指数DFI表示)检测结果进行回顾性分析。结果⑴感染组的精子浓度低于对照组,但差异无统计学意义(P>0.50);感染组的前向运动精子百分比低于对照组,但差异无统计学意义(P>0.20);⑵与对照组相比,感染组的精子DFI值显著升高,差异有统计学意义(P<0.05)。结论生殖道感染沙眼衣原体的男性不育患者的精子核DNA损伤程度明显高于未感染者。精子核DNA碎片化指数可能是评估男性精液质量的独立指标。     

不育男性精子中的顶体酶活性及精液参数研究

目的研究不育男性精子中顶体酶活性与精液参数。 方法选取我院收治的不育男性140例作为研究对象,再按照顶体酶参数是否正常划分为两组,观察组1（n=68）为精液参数正常组,即精液量、液化时间、外观、精子活力、外形以及数量等均无明显异常,观察组2（n=72）为精液参数异常组,即抗精抗体为阳性或上述检查有不少于1项明显异常,且存在生殖系统急慢性炎症史;选取1年内正常生育男性70例作为研究对象,设为对照组。应用手淫法对所有男性精液予以收集,且应用改良Kennedy法检测精子顶体酶活性,对比3组男性精子顶体酶活性。结果观察组2（a+b）级精子活动率明显低于其他两组（P<0.05）;对照组精子浓度明显高于观察组（P<0.05）;对照组顶体酶活性明显高于观察组1与观察组2（P<0.05）。 结论顶体酶活性低下密切关联于男性不育,检测不育男性精子中顶体酶活性临床价值重大,可将精子质量全面反映出来,进而评价其功能状态,有推广价值。       

改良的精子染色质扩散试验在人精子核DNA完整性检测中的应用

目的评价改良的染色质扩散试验在检测人精子核DNA完整性的应用价值。方法采用改良的精子染色质扩散试验分别对36例精液乙肝DNA阳性患者和36例正常男性进行精子DNA碎片率分析,评价方法的灵敏度。结果含有DNA碎片的精子头部无染色质扩散,DNA完整的精子显示"扩散光晕",在普通光学显微镜下根据"扩散光晕"容易检测出碎片精子率。精液HBV DNA阳性组的精子DNA碎片率显著高于对照组(P<0.001)。结论染色质扩散试验实验操作简便、快速、灵敏度高、特异性强,可用于90 min内快速检测人精子核DNA完整性。     

不育男性患者精浆 Ig A 型抗精子抗体对精液参数的影响

目的探讨精浆IgA型抗精子抗体(anti‐sperm antibody ,AsAb)对精液参数的影响.方法用酶联免疫吸附试验(ELISA)检测191例不育男性患者精浆的IgA型AsAb ,据此分为阳性和阴性两组,将两组患者的精液主要参数进行比较分析.结果精浆IgA型AsAb阳性组患者精子的密度、精子活率、精子总活力(PR+ NP)明显低于阴性组患者,差异具有统计学意义(P<0.01);两组患者的精液正常形态精子百分率差异无统计学意义(P>0.05).结论精浆IgA型AsAb不影响精液正常形态精子百分率,但能使精子的密度、活率、总活力明显降低,是导致男性不育的重要因素之一.     

男性不育患者病毒感染状况与精子密度、活率、形态的关系

目的 探讨男性不育患者病毒感染状况与精子密度、活率和精子形态的关系。方法 分析469例男性不育患者病毒感染状况，采用改良间接ELISA法进行病毒检测，用伊红-Y染色法分析精子活率，计算机自动分析精予活力，采用精子形态检测系统下人工修正方法进行精子形态分析。结果 469例男性不育精液样本中，检出病毒阳性率为8．32％，其中单纯疱疹病毒Ⅰ型1．92％，单纯疱疹病毒Ⅱ型2．56％，人类巨细胞病毒2．56％，风疹病毒1．28％。病毒感染阳性组精子密度和精子活率显著低于病毒感染阴性组（P〈0．05）；精子活力与病毒感染阴性组比较无显著性差异（P〉0．05）。病毒感染阳性组形态正常精子百分率与病毒感染阴性组比较，无显著性差异（P〉0．05），空泡样头精子和尾部缺陷精子百分率显著高于病毒感染阴性组（P〈0．05）。结论 单纯疱疹病毒和人类巨细胞病毒感染可导致精子密度和精子活率降低。     

精子染色质扩散试验及吖啶橙染色试验检测精子DNA完整性研究

目的 探讨精子染色质扩散(sperm chromatin dispersion,SCD)试验及吖啶橙染色(AO)试验检测精子DNA完整性的应用价值.方法 对32名已生育的成年男性健康对照者和27例特发性少精子症(idiopathic oligozoospermia,IO)患者同时进行SCD试验和AO试验,对检测结果 进行分析.在SCD试验中,DNA完整性正常精子的DNA扩散形成大晕环或中晕环,而受损伤产生DNA碎片的精子不形成或形成很小的晕环.用AO试验检测,正常精子DNA为双链,染成绿色,不成熟或损伤精子DNA为单链.染成红色、橙色或黄色.结果 SCD试验检测10患者的大晕环、中晕环、小晕环和无晕环精子百分率分别为(49.9±13.8)%、(11.5±5.4)%、(11.9±6.1)%和(26.7±10.0)%,健康对照组分别为(73.2±6.2)%、(14.7±6.3)%、(6.8±2.9)%及(5.3±2.2)%,2组比较,差异有统计学意义(t=8.576,P＜0.O1;t=2.083,P＜0.05;t=4.284,P＜0.01;t=11.823,P＜0.01);IO患者的DNA损伤精子的百分率为(38.6±12.1)%,健康对照组为(12.1±5.2)%,2组比较差异有统计学意义(t=11.995,P＜0.01).AO试验检测IO患者的单链DNA精子百分率为(45.5±13.8)%,健康对照组为(39.8±13.3)%,差异无统计学意义(t=1.626,P＞0.05).结论 精子DNA完整性异常可导致男性不育.SCD试验是一种有效的精子DNA完整性检测方法 .