褪黑素在活性氧致精子线粒体功能损伤中的保护作用

目的 :探讨活性氧 (ROS)对精子线粒体功能的损伤以及褪黑素 (MLT)的保护作用。　方法 :采用Percoll梯度离心法选择具有正常生理功能的精子 ,作为本实验的正常精子模型。应用次黄嘌呤—黄嘌呤氧化酶体系产生ROS ,在MLT存在与不存在情况下 ,与精子模型分别孵育 30和 6 0min后 ,采用酶组织化学方法分析精子线粒体部位的琥珀酸脱氢酶 (SDH)活性 ,采用Rhodamine 1 2 3(Rh1 2 3)荧光探针标记精子 ,通过流式细胞仪检测线粒体膜电位。　结果 :正常精子与ROS孵育后 ,精子线粒体膜电位明显降低 ,线粒体SDH活力降低极为显著 ;而MLT则减轻了ROS对精子线粒体功能的损伤。　结论 :ROS可通过对精子线粒体膜电位和SDH活力的影响 ,而导致精子线粒体功能损伤 ;MLT可通过其有效的抗氧化能力 ,保护精子对抗ROS对其线粒体功能的损伤     

尿激酶型纤溶酶原激活因子对小鼠获能精子线粒体膜电位的影响

目的:检测尿激酶型纤溶酶原激活因子(uPA)体外对小鼠获能精子线粒体膜电位的影响。方法:采用线粒体膜电位荧光染料JC-1,利用流式细胞仪和荧光显微镜检测分别与uPA(实验组)和BWW液(对照组)共孵育0、5、15、30、60min的小鼠获能精子线粒体膜电位状态。结果:①在uPA作用第5、15min时,精子体内平均荧光强度较作用前显著增加,高膜电位的精子数量百分率相应增加(P<0.05)。②与对照组相比,实验组在uPA作用5、15min时的高膜电位精子数量百分率,以及作用15、30、60min时的精子线粒体膜电位平均荧光强度显著增加(P<0.05)。结论:uPA在体外可以增加小鼠获能精子的线粒体膜电位,并使高膜电位状态维持一段时间,为获能精子提供充足的能量供应。     

孕酮趋化诱导人精子线粒体功能与ROS产生的关系

目的:使用计算机辅助精液分析仪和流式细胞分析仪,比较经上游法处理前后、孕酮诱导上游法处理前后精子线粒体相对活性以及活性氧自由基(ROS)阳性精子比例的变化,研究受精精子的线粒体功能特点。方法:收集正常人类精子(达到《世界卫生组织人类精液检查与处理实验室手册》第5版标准),利用"上游法"获能培养1 h,获得"获能前组"和"获能后组"精子。获能后组的精子继续在37℃和5%二氧化碳培养箱中,使用"孕酮诱导"垂直上游法再处理1 h,获得孕酮诱导超激活运动精子,分别称为"孕酮诱导组"和"对照组"。分别使用线粒体膜电位特异性染色剂JC-1和ROS染色剂DCF,标记人类精子线粒体膜电位,并计算线粒体相对活性指数,标记ROS阳性细胞比例。结果:正常人类精子经获能处理及继续垂直上游后,线粒体相对活性(高活性线粒体/低活性线粒体比值)显著上升。获能前组、获能后组、对照组和孕酮诱导组的线粒体活性分别为1.42、6.23、14.36和12.33;获能前组、获能后组、对照组和孕酮诱导组含有均衡线粒体(含有等量高膜电位和低膜电位的线粒体)比例分别为21.64%、4.27%、5.03%和8.57%,说明孕酮诱导能够在激活线粒体活性的同时,维持低活性线粒体的比例。ROS同时在精子的头、颈、尾部出现,获能前组、获能后组、对照组和孕酮诱导组ROS阳性细胞比例分别为2.89%、0.7%,4.25%和1.90%。上游1 h后的精子ROS阳性比例显著低于上游前精子。再经过1 h垂直上游后,"对照组"精子的ROS阳性比例大大增加;孕酮诱导组精子的ROS阳性比例显著低于"对照组"。结论:孕酮体外诱导上游精子,能够显著提高精子运动速度,使其呈现超激活运动状态,同时抑制精子的线粒体相对活性持续增高,保持线粒体活性均衡,降低ROS产量,可能有利于体外受精率和胚胎质量的提高。     

JC-1单标法检测精索静脉曲张患者精子线粒体膜电位的研究

目的:检测精索静脉曲张患者精子线粒体膜电位并探讨其临床意义。方法:将67例精索静脉曲张患者分为VC1组(精索静脉曲张1度,n=26)、VC2组(精索静脉曲张2度,n=21)和VC3组(精索静脉曲张3度,n=20),以正常生育男性为正常对照组(n=29)。通过计算机辅助精液分析系统进行精液常规分析。精液标本洗涤处理后用荧光染料JC-1染色后上流式细胞仪分析,检测精子线粒体膜电位(JC-1+%)。结果:VC1、VC2、VC3组精子线粒体膜电位[(56.29±16.32)%,P<0.05;(45.04±13.21)%,P<0.01;(31.63±12.91)%,P<0.01]均显著低于正常对照组[(76.21±13.96)%]。96例标本中,JC-1+%与(a+b)级精子百分率呈显著正相关(r=0.693,P=0.000)。结论:精索静脉曲张可引起精子线粒体膜电位降低,可能是导致男性不育的重要原因之一。     

正常精子体外与活性氧作用后超微结构观察

目的 :观察精子与活性氧 (ROS)作用后超微结构变化。　方法 :采用Percoll梯度离心法选择具有正常生理功能的精子作为正常精子模型 ,应用次黄嘌呤 黄嘌呤氧化酶体系产生ROS ;在有氧环境下ROS与精子模型孵育后 ,采用透射电镜观察精子超微结构。　结果 :正常精子模型与ROS作用后 ,精子膜及顶体存在不同程度的损伤 ,精子线粒体结构出现异常。　结论 :过多的ROS可致精子膜、顶体以及线粒体的超微结构改变 ,损害精子功能。     

线粒体氧化磷酸化抑制剂FCCP体外对人精子动力学和线粒体功能的影响

目的通过线粒体氧化磷酸化(OXPHOS)特异性抑制剂FCCP对人精子活动力及其线粒体功能影响的研究,探讨氧化磷酸化在精子能量代谢中的作用。方法选择来自捐精志愿者的正常精液8份,优选后制备精子悬液,将每份精子悬液分为4组,分别与终浓度为0μmol/L(对照组)、2.5μmol/L、5μmol/L和10μmol/L的FCCP共孵育1h、3h、5h,以精子动力学参数、线粒体膜电位、精子细胞内ATP含量、精子质膜完整性作为评价指标,分析比较各组间的差异。结果 (1)各组精子活动率和其他各项运动参数随着FCCP浓度增高呈下降趋势:孵育1h后,与对照组相比,仅10μmol/L组的精子活动率、前向运动百分率和精子头侧摆幅度(ALH)显著下降(P0.05),其余指标无显著性变化,而其余浓度处理组的各指标变化均无统计学意义(P0.05);孵育3h后,10μmol/L组的精子活动率、前向运动百分率、平均路径速率(VAP)、直线速率(VSL)、曲线速率(VCL)、ALH和鞭打频率(BCF)均显著降低(P0.05),5μmol/L组的ALH和BCF指标显著下降(P0.05);孵育5h后,与对照组相比,10μmol/L组的前述指标继续显著性下降(P0.05),5μmol/L组的精子活动率和前向运动百分率也出现显著降低(P0.05),而2.5μmol/L组各指标差异均无统计学意义(P0.05)。(2)精子线粒体膜电位(MMP)和ATP含量随FCCP浓度增加逐渐降低,10μmol/L组的MMP和ATP含量显著低于对照组(P0.05)。(3)质膜完整性比较中,10μmol/L组比对照组显著降低(73.94%vs.84.53%)(P0.05)。(4)随着FCCP孵育时间延长,各组精子活动率和前向运动百分率呈下降趋势。结论不同浓度的FCCP体外处理精子后,精子活动率和其他各项运动参数,以及反映线粒体活性的线粒体膜电位和ATP含量呈浓度依赖性下降,FCCP所抑制的线粒体氧化磷酸化是精子能量代谢的重要途径。     

益精方对特发性少弱精子症精子凋亡和线粒体功能影响的研究

目的:观察益精方对特发性少弱精子症精子凋亡和线粒体膜电位水平的影响。方法:采用自身前后对照的临床试验设计方法,观察益精方对30例特发性少弱精子症治疗前后精子凋亡率和线粒体膜电位的变化情况。结果:30例特发性少弱精子症患者精子早期凋亡率(AV+/PI-)治疗前为(4.26±2.79)%,治疗后为(2.86±1.47)%,线粒体膜电位(MMP)丧失率治疗前为(41.73±20.30)%,治疗后为(21.77±13.46)%,精子早期凋亡率和线粒体膜电位丧失率治疗前后比较有统计学差异(P<0.05);精子晚期凋亡和死亡率(PI+)治疗前为(34.10±16.26)%,治疗后为(30.21±13.50)%,治疗前后比较无统计学差异(P>0.05)。结论:益精方可以降低精子早期凋亡率,提高精子线粒体功能,这可能是益精方治疗少弱精子症的一个重要途径。     

白藜芦醇对人精子冷冻损伤的保护作用

目的:通过在人精子冷冻保护液中添加白藜芦醇,研究其对冻融后精子质量和功能的影响。方法:选择正常精液与少弱精子症样本各50例,液化后的精液样本分别与甘油-卵黄-柠檬酸盐(GEYC)冷冻保护液或含有30μmol/L白藜芦醇的GEYC冷冻保护液混匀。冷冻复苏前后,进行精子活力、存活率及顶体反应分析。采用丙二醛(MDA)及活性氧(ROS)检测试剂盒评估精子脂质过氧化程度及ROS水平。通过罗丹明123(Rh123)染色法及TUNEL试验检测精子线粒体膜电位及DNA损伤。结果:在正常精液和少弱精子症样本组中,与各组冷冻前新鲜精液相比,冻融后前向运动精子百分率、总活力、存活率、线粒体膜电位及顶体反应率均显著下降(P0.05),而精子ROS、MDA水平和DNA碎片指数(DFI)均显著升高(P0.05)。冷冻保护液中添加30μmol/L白藜芦醇后,正常精液组前向运动精子百分率[(43.1±6.3)%]、总活力[(56.9±7.4)%]、存活率[(67.5±5.6)%]、线粒体膜电位[(63.4±7.5)%]及顶体反应百分率[(26.3±4.7)%]较冷冻对照(未加白藜芦醇)的前向运动精子百分率[(32.7±4.8)%]、总活力[(44.8±6.9)%]、存活率[(52.3±6.1)%]、线粒体膜电位[(56.5±7.0)%]及顶体反应百分率[(16.6±3.8)%]均显著提高(P0.05),而精子ROS、MDA水平和DFI较冷冻对照均显著降低(P0.05)。在少弱精子症组中,添加白藜芦醇也均显著地提高了冷冻后精子前向运动百分率、总活力百分率、存活率、线粒体膜电位及顶体反应百分率,尤其是DFI[28.5±4.8)%]较冷冻对照[(36.3±5.7)%]显著降低(P0.01)。结论:在精液冷冻保护液中添加白藜芦醇可以通过降低精子内ROS水平减少精子冷冻损伤,从而改善解冻后精子质量和功能。     

番茄红素对人精子冷冻损伤的保护作用及机制研究

目的:通过在人精子冷冻保护液中添加不同浓度的番茄红素,研究番茄红素对精子冷冻损伤的可能保护作用及机制。方法:选择吉林省人类精子库捐精者的精液标本25份,每份精液一式4份,3∶1加入冷冻保护液后混匀,不含番茄红素者设为对照组(Ly0),而Ly2、Ly5、Ly10实验组混合液中分别含有2、5、10μmol/L的番茄红素,冷冻复苏精液进行常规分析,采用流式细胞术分析冻融后各组精子的凋亡率;采用硫代巴比妥酸(TBA)比色法检测精子中脂质过氧化产物丙二醛(MDA)浓度。利用JC-1标记法检测线粒体膜电位。结果:冻融后各组精子运动参数较新鲜精液参数均明显下降(P<0.01),Ly5组冻融后精子凋亡率[(25.68±4.36)%]较对照组[(33.26±4.78)%]显著下降(P<0.05);Ly5组线粒体膜电位水平[(66.18±14.23)%]显著高于对照组[(55.24±12.31)%],P<0.05;Ly2、Ly5、Ly10组的MDA水平与对照组比较,无统计学差异(P>0.05)。结论:在精液冷冻保护液中添加一定浓度的番茄红素可以减少线粒体氧化损伤,减轻活性氧对精子质膜的氧化应激损伤,从而提高精子的抗凋亡能力。     

精子线粒体琥珀酸脱氢酶的检测及意义

目的 :采用一种简便、快速的检测精子线粒体琥珀酸脱氢酶 (SDH)的改良方法检测精子SDH ,并评价其与精子活动率及存活率的关系。　方法 :4 6例年龄为 2 5～ 36岁 (平均 31岁 )生育与不育男性精液标本 ,采用计算机辅助精液分析系统检测精子活动率 ,应用改良SDH检测法检测精子SDH ,通过死、活精子荧光分子探针染色检测精子存活率 ,分析精子活动率、存活率及精子SDH阳性率之间的关系。　结果 :4 6例生育与不育男性精子活动率为( 6 7.33± 7.37) % ,存活率为 ( 79.78± 7.6 5 ) % ,精子SDH阳性率为 ( 74 .74± 8.2 9) % ;精子活动率、存活率及精子SDH阳性率 3者之间均存在显著相关性 (P均 <0 .0 1)。　结论 :精子线粒体SDH检测对评价精子线粒体功能具有重要意义 ,还可作为精子存活率的辅助指标     

Protection of melatonin against damage of sperm mito-chondrial function induced by reactive oxygen species

Aim: To study the mitochondrial function damage of sperm in-duced by reactive oxygen species (ROS) and the protection of melatonin (MLT) against the damage. Methods: Normal function spermatozoa were selected from semen samples by Percoll gradi-ent centrifugation technique. The ROS generated by the hypoxan-thine xanthine oxidase system was incubated with the normal sper-matozoa in the presence or absence of MLT (6 retool/L) for 30 and 60 minutes.     

Effects of semen processing on the generation of reactive oxygen species and mitochondrial membrane potential of human spermatozoa

This study was designed to evaluate the effects of semen processing on the generation of intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in spermatozoa, and to develop reliable indexes for the evaluation of sperm quality during sperm preparation. Swim-up and density gradient centrifugation methods were used to separate semen in oligoasthenoteratozoospermia (OAT), leucocytospermia (LC) and normozoospermia groups. Levels of ROS and MMP were measured by flow cytometry. Before preparation, the patients with abnormal semen parameters had a lower MMP and higher ROS, and there was a negative correlation between MMP and ROS. The levels of MMP and ROS increased significantly, especially ROS produced by swim-up. A significant difference was found between the correlation of MMP and total normal motile sperm count after preparation in the OAT group. The level of ROS was associated with the amount of white blood cells in the LC group. The MMP can be used as an objective index to evaluate the sperm quality of OAT patients, and the combination of MMP and ROS can be used to assess the efficiency of sperm preparation in LC patients. These findings can guide selection of the ideal sperm separation technique for different sperm samples.     

Effects of reactive oxygen species from activated leucocytes on human sperm motility, viability and morphology

The accumulated data suggest that inflammation can increase the level of reactive oxygen species (ROS), which contribute to impaired sperm function and male infertility. Therefore, we propose that inflammation-mediated production of ROS in male and female reproductive tracts hinder sperm fertilisation. To test this hypothesis, phorbol myristate acetate (PMA) with polymorphonuclear leucocytes (PMNs) was applied to generate endogenous ROS. We evaluated the time-dependent effects of ROS on human sperm motility, viability and mitochondrial membrane potential (MMP). The results showed that after treatment with PMA and PMNs, the motility of human spermatozoa significantly decreased to 50% on Day 1 and 15% on Day 4 compared with that of the, respectively, negative controls (P = 0.012). The viability of human spermatozoa decreased on Day 4 of PMA + PMNs treatment (P = 0.028). The MMP of human spermatozoa significantly decreased from Day 2 to Day 4 in the PMA + PMN group compared with that of the controls (P = 0.019). Taken together, the 4-day cultivation approach provided an accurate evaluation of sperm quality, especially sperm motility and MMP. Our findings indicated that endogenous inflammation increased ROS levels, which might induce sperm oxidative damage. Additionally, sperm motility might be one of the earliest and most sensitive indicators of this damage.     

The effect of reactive oxygen species on equine sperm motility, viability, acrosomal integrity, mitochondrial membrane potential, and membrane lipid peroxidation

The objective of this study was to examine the influence of reactive oxygen species (ROS), generated through the use of the xanthine (X)-xanthine oxidase (XO) system, on equine sperm motility, viability, acrosomal integrity, mitochondrial membrane potential, and membrane lipid peroxidation. Equine spermatozoa were separated from seminal plasma on a discontinuous Percoll gradient, and spermatozoa were incubated with 0.6 mM X and 0.05 U/mL XO for 30 minutes. Catalase (150 U/mL), superoxide dismutase (SOD, 150 U/mL), or glutathione (GSH, 1.5 mM) were evaluated for their ability to preserve sperm function in the presence of the induced oxidative stress. At the end of the 30-minute incubation, sperm motility was determined by computer-assisted semen analysis. Viability and acrosomal integrity were determined by Hoechst-Pisum sativum staining, and mitochondrial membrane potential was determined by staining with JC-1. Incubation with the X-XO system led to a significant (P < .01) increase in hydrogen peroxide production and an associated decrease (P < .01) in motility parameters. Total motility was significantly (P < .01) lower in the presence of X-XO compared with the case of the control (29%+/-9% vs 73%+/-1%, respectively). Catalase, but not SOD, prevented a decline in motility secondary to oxidative stress (71%+/-4% vs 30%+/-3%, respectively). The addition of glutathione had an intermediate effect in preserving sperm motility at the end of the 30-minute incubation (53%+/-3%). No influence of X-XO could be determined on viability, acrosomal integrity, or mitochondrial membrane potential. In order to promote lipid peroxidation, samples were incubated with ferrous sulfate (0.64 mM) and sodium ascorbate (20 mM) for 2 hours after the X-XO incubation. No increase in membrane lipid peroxidation was detected. This study indicates that hydrogen peroxide is the major ROS responsible for damage to equine spermatozoa. The decrease in sperm motility associated with ROS occurs in the absence of any detectable decrease in viability, acrosomal integrity, or mitochondrial membrane potential or of any detectable increase in lipid peroxidation.     

活性氧致人精子运动功能和存活力变化的分析

目的 :对活性氧 (ROS)作用后精子的运动参数和存活率的变化进行分析 ,以证实ROS是否为引起精子运动功能障碍的病因之一。　方法 :采用Percoll梯度离心法选择具有正常生理功能的人精子作为正常精子模型 ,应用次黄嘌呤 黄嘌呤氧化酶体系产生ROS ,在有氧环境下与精子模型孵育后 ,运用计算机辅助精液分析 (CASA)系统 ,分析ROS攻击后精子运动参数的改变。　结果 :与对照组相比 ,正常精子模型与ROS孵育 30min后 ,精子活动率、曲线速度 (VCL)、直线速度 (VSL)、平均路径速度 (VAP)均明显下降 (P <0 .0 0 1) ,头侧摆幅度 (ALH)尚无明显改变 (P >0 .0 5 ) ,而与ROS孵育 6 0min后 ,精子运动功能近乎丧失 ,精子主要运动参数趋向于零。　结论 :ROS与正常精子作用后 ,可导致精子运动功能下降 ,从而证实ROS为精子运动功能障碍的病因之一。     

Effect of mitochondrial calcium uniporter blocking on human spermatozoa

Calcium (Ca²⁺) regulates a number of essential processes in spermatozoa. Ca²⁺ is taken up by mitochondria via the mitochondrial calcium uniporter (mCU). Oxygen‐bridged dinuclear ruthenium amine complex (Ru360) has been used to study mCU because it is a potent and specific inhibitor of this channel. In bovine spermatozoa, it has been demonstrated that mitochondrial calcium uptake inhibition adversely affects the capacitation process. It has been demonstrated in human spermatozoa that mCU blocking, through Ru360, prevents apoptosis; however, the contribution of the mCU to normal human sperm function has not been studied. Therefore, the aim of this study was to evaluate the effect of mCU blocking on human sperm function. Spermatozoa obtained from apparently healthy donors were incubated with 5 and 10 μm Ru360 for 4 h at 37 °C. Viability was assessed using propidium iodide staining; motility was determined by computer‐aided sperm analysis, adenosine triphosphate (ATP) levels using a luminescence‐based method, mitochondrial membrane potential (ΔΨm) using JC‐1 staining and reactive oxygen species (ROS) production using dihydroethidium dye. Our results show that mCU blocking significantly reduced total sperm motility and ATP levels without affecting sperm viability, ΔΨm and ROS production. In conclusion, mCU contributes to the maintenance of sperm motility and ATP levels in human spermatozoa.     

The effect of cysteine and glutamine on human sperm functional parameters during vitrification

Assuming the adverse effects of reactive oxygen species (ROS) on sperm function, this study was conducted to assess the effects of cysteine and glutamine as effective antioxidants on human sperm parameters under vitrification. Twenty normozoospermic samples were used. The samples were subjected to a vitrification process and cysteine (5 and 10 mM) and glutamine (10 and 15 mM). The sperm motility parameters, mitochondrial membrane potential (MMP), plasma membrane integrity (PMI), DNA damage and intracellular ROS damage were assessed for each sample. Statistical analyses showed that motility, mitochondrial membrane potential and DNA damage decreased in the vitrified groups with cysteine 5, 10 mM and glutamine 10, 15 mM separately. Also intracellular ROS increased significantly compared to the fresh group (p < .05). No significant differences were observed for PMI compared with the fresh group (p > .05). Supplementation of cysteine and glutamine in both concentrations separately decreased intracellular ROS and DNA damage of spermatozoa with significant increase in PMI, MMP and progressive motility compared to vitrified control group (p < .05). The results showed no significant effect of a specific concentration in cysteine and glutamine on sperm parameters compared to other concentrations. Both amino acids have the potential to improve the harmful effects of freezing on sperm parameters.     

氧化胁迫与精子功能损伤

人类精子对氧化胁迫特别敏感 ,损伤精子功能的氧化胁迫有两个细胞来源 :精子自身和白细胞。由于精子膜含有高浓度的不饱和脂肪酸 ,而且精子自身的抗氧化能力很弱 ,在过量活性氧的攻击下 ,易发生脂类过氧化反应 ,使精子膜的流动性和完整性受到损伤 ,进而破坏精子功能 ,并最终引起男性不育。此外 ,过量的活性氧还可造成精子核DNA的损伤 ,而父代精子DNA的损伤又与子代儿童癌症的发生有密切的关联。     

Causes and consequences of sperm mitochondrial dysfunction

Mitochondria have multiple functions, including synthesis of adenine triphosphate, production of reactive oxygen species, calcium signalling, thermogenesis and apoptosis. Mitochondria have a significant contribution in regulating the various physiological aspects of reproductive function, from spermatogenesis up to fertilisation. Mitochondrial functionality and intact mitochondrial membrane potential are a pre-requisite for sperm motility, hyperactivation, capacitation, acrosin activity, acrosome reaction and DNA integrity. Optimal mitochondrial activity is therefore crucial for human sperm function and semen quality. However, the precise role of mitochondria in spermatozoa remains to be fully explored. Defects in sperm mitochondrial function severely impair the maintenance of energy production required for sperm motility and may be an underlying cause of asthenozoospermia. Sperm mtDNA is susceptible to oxidative damage and mutations that could compromise sperm function leading to infertility. Males with abnormal semen parameters have increased mtDNA copy number and reduced mtDNA integrity. This review discusses the role of mitochondria in sperm function, along with the causes and impact of its dysfunction on male fertility. Greater understanding of sperm mitochondrial function and its correlation with sperm quality could provide further insights into their contribution in the assessment of the infertile male.