Lipid peroxidation and large-scale deletions of mitochondrial DNA in asthenoteratozoospermic patients.

The correlation between malondialdehyde (MDA) an index of lipid peroxidation (LPO) with large-scale deletion mitochondrial DNA (mtDNA) was investigated in a case-control study with a total of 50 semen samples from infertile men, including 25 normozoospermic donor as the control group and 25 asthenoteratozoospermic (AT) patients as the case group. Routine semen analysis was performed according to World Health Organization (WHO, 1999) guidelines. MDA levels of the seminal plasma and spermatozoa were measured by TBARS method. A long-range polymerase chain reaction (PCR) method was used for the analysis of multiple large-scale mtDNA deletions based in two areas of mtDNA. The results showed that mean concentration of MDA in seminal plasma (nmol/ml) and spermatozoa (nmol/10 × 106 sperm) of AT men was higher than in normozoospermic patients, but the differences were not statistically significant. The products of PCR analysis showed multiple deletions of ~4.7, 4.8, 7.2, 7.3 and 7.4-kb in mtDNA of the spermatozoa in both AT and control groups. Multiple deletions were also observed in 64% of AT patients and 44% of the control group. Moreover, MDA level of the spermatozoa in deleted mtDNA samples group was significantly higher than in non-deleted mtDNA group (p = 0.01). Our findings indicated a positive correlation between increased MDA levels and large-scale mtDNA deletions in human spermatozoa. It is suggested that LPO or other oxidative stress factors might be causative elements in mtDNA damage, effect on sperm motility and morphology, resulting in decline of fertility in men.

Oxidative stress and sperm mitochondrial DNA mutation in idiopathic oligoasthenozoospermic men.

Physiological function of reactive oxygen species (ROS) has been known since a long, but recently toxic effects of ROS on spermatozoa have gained much importance in male infertility. Mitochondrial DNA (mtDNA) is believed to be both source and target of ROS. mtDNA unlike nuclear DNA is not compactly packed and hence more susceptible to oxidative stress (OS) than nuclear DNA. In the present study, the role of OS in mitochondrial genome changes was studied in men with idiopathic infertility. The study included 33 infertile oligo-asthenozoospermic (OA) men and 30 fertile controls. Semen analyses were performed and OS was measured by estimating the level of malondialdehye (MDA) in the seminal plasma and ROS in the sperm. Sperm mtDNA was sequenced by standard PCR-DNA sequencing protocol for ATPase and nicotinamide adenine dinucleotide dehydrogenase (ND) groups of genes. Sperm count and progressive motility were found to be significantly lower in infertile group than the fertile controls. Semen MDA and ROS levels of infertile group were significantly higher (p<0.0001), when compared to the control group. However, catalase and glutathione peroxidase (GPx) levels were significantly lower in infertile group, compared to controls, but no significant difference in superoxide dismutase (SOD) activity was observed between control and cases. This might be due to higher expression of SOD alone in order to overcome OS in the semen. mtDNA analysis showed significant and high frequency of nucleotide changes in the ATPase (6 and 8), ND (2, 3, 4 and 5) genes of infertile cases compared to the controls. Hence excess ROS and low antioxidant levels in the semen might cause mtDNA mutations and vice versa in OA men that might impair the fertilizing capacity of spermatozoa. Thus, it is important to understand the etiology of mitochondrial genome mutations in idiopathic OA cases for better diagnostic and prognostic value in infertility treatment/assisted reproductive technique

Activity of antioxidant enzymes in seminal plasma and their relationship with lipid peroxidation of spermatozoa

PURPOSE: To determine the activity of seminal plasma catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) and their relationship with malondialdehyde (MDA), as a marker of lipid peroxidation, content of spermatozoa and seminal plasma in normozoospermic and asthenozoospermic males. MATERIALS AND METHODS: Semen samples were obtained from 15 normozoospermic and 30 asthenozoospermic men. RESULTS: We observed inverse correlations between activities of CAT (k/mL) and SOD (U/mL) in seminal plasma with MDA content of spermatozoa from normozoospermic samples (r =- 0.43, p < 0.05 and r =- 0.5, p < 0.05, respectively). Significant correlations were observed between total activity CAT (k/total seminal plasma) with total SOD (U/total seminal plasma) and GPX activity (mU/total seminal plasma) in seminal plasma from normozoospermic samples (r = 0.67, p = 0.008 and r = 0.455, p = 0.047, respectively). Furthermore, we found positive correlations between total activities of CAT, SOD and GPX with total content of MDA in seminal plasma (nmoL/total seminal plasma) from normozoospermic samples (r = 0.67, p = 0.003; r = 0.73, p = 0.003; r = 0.74, p = 0.004, respectively). In asthenozoospermic samples, there were no significant correlations observed between activities of CAT (k/mL), SOD (U/mL) and GPX (mU/mL) of seminal plasma with MDA content of spermatozoa. However, we found significant correlations between total activities of CAT (k/total seminal plasma) and SOD (U/total seminal plasma) with total content of MDA in seminal plasma (r = 0.4, p = 0.018 and r = 0.34, p = 0.03, respectively). CONCLUSION: These findings indicate a protective role for antioxidant enzymes of seminal plasma against lipid peroxidation of spermatozoa in normozoospermic samples.