Assessment of correlation between asthenozoospermia and mitochondrial DNA mutations in Egyptian infertile men

Abstract

Background

Asthenozoospermia is a chief reason for male seminal pathologies with an impression of around 19% of infertile patients. Spermatozoa mitochondrial DNA variations seem to link with low sperm motility. The objective of the study was to assess the relation between mitochondrial mutations and male sterility, especially in asthenozoospermia. The patient semen samples were investigated by studying the sperm physical characters; motility, viability, and morphological parameters were then classified into normozoospermia and asthenozoospermia. In addition, the level of malondialdehyde (MDA) as a bio-indicator of lipid peroxidation, seminal fructose, and total antioxidant capacity (TAC) were estimated. For molecular analysis, DNA from the semen samples was extracted using a DNA extraction kit. ND1, ND2, and ATPase6 genes were amplified by using a specific primer. After the purification procedure, each PCR product was sequenced to identify the single nucleotide polymorphisms (SNPs) in selected genes.

Results

A significant negative correlation between seminal plasma malondialdehyde levels and sperm motility was detected. Meanwhile, TAC analysis revealed significantly lower activity ( p ≤ 0.05) in the sample of asthenozoospermic than in normozoospermic men. As regards the seminal plasma fructose, there was no significant difference in the fructose level of normozoospermia and asthenozoospermia cases. At the molecular level, 31 diverse nucleotide substitutions were recognized in mitochondrial DNA. Only ten (10) mutations led to amino acid transformation: four have deleterious effects, four are benign, and the other two have conflicting effectiveness.

Conclusions

This study is the first in Egypt that is concerned with studying the relationship between the mitochondrial DNA mutations in human spermatozoa of asthenozoospermic patients and fertility. The results displayed scientific indications evidenced that there is an association between mitochondrial mutations and male infertility.