Assessment of correlation between mitochondrial DNA mutations and sperm dysfunction in infertile men

Abstract

Infertility could be described as a global socio-economical problem; Up to 15 percent of couples are infertile worldwide. This means that up to half of these couples aren't able to conceive a child even though they have frequent, unprotected sexual intercourse for a year or longer. Male infertility is due to low sperm production, abnormal sperm function or blockages that prevent the delivery of sperms. Illnesses, injuries, chronic health problems, lifestyle choices and other factors can play a role in causing male infertility. Sperm motility is an imperative male fertility determinant and mitochondria are a crucial cell organelle to create energy for sperm motility. As mitochondrial energy metabolism is a main factor supporting numerous sperm functions, its host serious metabolic pathways through the development and fertilization. In this study two groups; the control group (normozoospermic) which has normal sperm motility and the other one suffering of low sperm motility (Asthenozoospermic) were investigated. Evaluation of sperm physical characters was done according to WHO guidelines fifth edition. Level of oxidative stress was determinated by MDA calorimetrically. Also, the fructose level and total antioxidant capacity was evaluated. The total DNA from the sperm cells was isolated using the DNA kit. The ND1, ND2 and ATPase6 mitochondrial genes were amplified using two sets of PCR primers, which were located in the flanking regions of each gene. The bands were excised from the agarose gel and purified using a Thermo gel band purification kit. The sequencing was done by Macrogen Incorporation (Seoul, Korea). The variations were imported into BioEdit sequence alignment editor version 7.2.1 and aligned with the reference human mtDNA, where the mutations at the various points were identified and recorded.