Infertility remains a major problem in society, with recent data suggesting its presence in one of four couples. The objective of the present study was to evaluate the impact of nicotine (0.25, 0.5 and 0.75 mm), as a major component of cigarette smoke, in vitro, on sperm membrane [by spermatocrit and lipoperoxidation (LPO) tests], DNA integrity (by Comet assay), and viability of spermatozoa (by eosin staining) from normozoospermic men. Sperm samples were washed and diluted with phosphate-buffered saline. A drop in spermatocrit values and an increase in thiobarbituric acid-reactive substances/LPO rate was observed with the addition of nicotine, predominantly at a concentration of 0.75 mm, indicating a deleterious effect of nicotine on sperm membrane intactness. There was also a strong negative correlation between LPO rate and percentage viable sperm cell (r = -0.990). Data obtained from Comet assay technique revealed that nicotine could induce double-stranded DNA breaks (11% in 0.75 mm concentration) in the sperm nuclei. The value of r between LPO rate and percentage Comets was found to be +0.976. Taken together, nicotine proved to be a potential oxidant agent in the category of environmental factors to the integrity of sperm plasma membrane and DNA.

Numerous investigations have been conducted on the relationship between cigarette smoking and male infertility, however, the exact molecular mechanisms are not well understood in most of the cases. Few studies have indicated the direct effect of seminal plasma (SP) [in different dilutions with phosphate buffer solution (PBS)] from smokers (SM) on the sperm functional parameters from nonsmokers (non-SM). The aim of this study was to provide evidence that cigarette smoking affects male fertility via altering the sperm quality. Our results indicated that exposure of spermatozoa from the non-SM to the SP from the SM yielded a significant reduction in the sperm motility and acrosome reaction and an elevation in the amount of malondialdehyde (MDA), in a certain time course. Exposure of spermatozoa from the SM to the SP from the non-SM or with PBS resulted in the nonsignificant improvement in the altered sperm functional parameters indicating removal of SM's SP and then subsequent reconstitution with physiological media could be of clinical significance in the various assisted reproductive technologies applied for SM. However, the detrimental effect of SM's SP on non-SM's spermatozoa was prominent. In addition, as spermatozoa in SM's SP are susceptible to peroxidative damages, men with such cells who wish to have children should especially benefit from quitting smoking.

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Purpose Sperm that bypass natural apoptosis and the ubiquitin-proteasome system may find their way into semen.In order to avoid the insemination of such sperm during an intracytoplasmic sperm injection (ICSI) treatment, novel sperm selection procedures such as the Zeta procedure have been implemented. Therefore, the aim of this study was to evaluate extent of ubiquitination and external phosphatidylserine (EPS) in sperm populations selected by combines density gradient centrifugation (DGC) and Zeta electric potential in comparison to DGC and neat semen samples. Methods Semen samples were collected from 51 infertile men and divided into control, DGC and DGC-Zeta groups. Semen analysis was carried out according to World Health Organization criteria. The percentages of protamine deficiency, DNA fragmentation, EPS and ubiquitinated sperm were assessed by chromomycin A3 (CMA3), TUNEL, Annexin V, and immunostaining, respectively. Results Sperm selected by the DGC-Zeta procedure presented a lower percentage of sperm with protamine deficiency, abnormal morphology and DNA fragmentation while the percentage of annexin V and ubiquitin-positive sperm increased. Conclusion The results of this study reveal that, DGC-Zeta improves the quality of the selected spermatozoa for ICSI and increases ubiquitination and EPS rates. We propose these alterations are part of the normal physiological process of capacitation.

Cadmium (Cd) is a widespread environmental pollutant. Because of its long biological half-life (10-30 years in humans), Cd accumulates in the biological systems such as gonads. The present study was designed to evaluate the effect of Cd in the concentration range 50-750 micromol/L, in vitro, on the membrane integrity, motility and acrosomal status of bull spermatozoa. The samples were processed for sperm analyses using semen-diluting fluid (phosphate-buffered saline, pH 7.2). A significant elevation in the malondialdehyde level/lipid peroxidation (LPO) rate and a decrease in the spermatocrit values, particularly at a concentration of 750 micromol/L Cd, indicated the deleterious effect of Cd on sperm membrane integrity. There was also a negative correlation between LPO rate and percentage of motile spermatozoa (r = 0.992). The gelatin test indicates that Cd may alter the integrity of acrosomal membranes and shows an abnormal acrosome reaction. In this regard, a strong negative correlation was found between LPO rate and % halos (bright clear zone around sperm heads after gelatin digestion) (r = 0.990). Taking the results together, Cd proved to be a potential toxicant in the category of environmental factors that induce membrane impairment, lower motility, and decrease the rate of acrosome reactions, leading to male infertility. Apparently, the presence of Cd in the environment and seminal plasma exerts a toxic effect on sperm cells.