Objectives: A spermatozoa-mitochondrial DNA (Sp-MtDNA) rearrangement is one of several etiologies of male infertility. The molecular base of this defect must be clarified to inspect the cause of diminished sperm fertility. This work has been designed to evaluate the Sp-MtDNA mutations as a candidate issue for males'-infertility. Methods: The study included 56 asthenozoospermic and 30-fertile males. A semen sample was collected from all participants. Direct sequencing was performed after the mitochondrial ATPase-8 gene (MtATPase-8) was amplified by PCR. Results: A novel nucleotide substitution was recognized significantly in the MtATPase-8 of all patients in progressive and non-progressive motility sperm cells, but absent in the normozoospermic controls. One missense novel substitution 8378A>G in the MtATPase-8 detected characterized by alteration of amino-acids ''Asn to Asp''. This substitution was persistent in the ≤ 5% group of sperms-motility, which was 7.5%, with lower frequencies in other sperms-motility groups. Non-progressive motility sperm portions were found to have the highest frequencies of the identified mutations, which had isolated from a 40% gradient in the ≤ 5% sperm-motility group. The latter represented 7.5% for 8378A>G mutation, instead of progressively motile sperms isolated from the 80% gradient portion.
Conclusion: In the current work, the mutation of Sp-MtDNA reveals a vital role in fertility and sperm motility attenuation, which are significant elements of male fertility. Moreover, in infertile men, the incidence of Sp-MtDNA novel mutation is highly frequent.