الفهرس 
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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.
The physical and biochemical results: Our findings; revealed that the percentages of the total and progressive motility of spermatozoa were significantly low in asthenozoospermic infertile men as compared to those of normozoospermic men. Sperm count was significantly decreased in the infertile asthenozoospermic men than those of the normozoospermia men. Differences between fertile and infertile men were significant for sperm morphology, teratozoospermia index and acrosome index. The level of malondialdehyde (MDA) in seminal plasma of the asthenozoospermic men was significantly higher than in healthy normozoospermia fertile men. Seminal total antioxidants capacity analysis revealed significantly lower activity in asthenozoospermia compared to normozoospermia. While, fructose level in seminal plasma indicated no significance difference between normozoospermia and asthenozoospermia cases.
In normozoospermia, there was a negative correlation between motility with MDA levels (r = - 0.082), sperm concentration (r = - 0.229) and acrosome index (r = - 0.0012). While this correlation was positive between motility and total antioxidant capacity (r = 0.098), seminal fructose level (r = 0.201) and morphology (r = 0.184).
In asthenozoospermia, there was a negative correlation between motility with MDA levels (r = - 0. 282), sperm morphology (r = - 0. 349) and TZI (r = - 0.291) and acrosome index (r = - 0. 005). Although, the correlation between motility and sperm concentration (r = 0. 0.408), total antioxidant capacity (r = 0. 052), seminal fructose level (r = 0. 144) were significantly positive (P ≤ 0.05).
The molecular results: The net polymorphic sites observed in the sequenced mtDNAs regions are 31 diverse nucleotide substitutions, of which 10 non synonymous mutations that produced an amino acid variation and 21 synonymous mutations that did not cause any amino acid change.
In addition, the sequence analysis of the studied genes revealed that all base substitutions were transition except an insertion at nucleotide position 4169 (T) was detected in ND1, a deletion at nt. 4613 (A) and transversion C to A at nucleotide number 5331 were noticed in ND2.
The Ten non- synonymous leads to amino acid transformation were four have deleterious effect; four are benign and two mutations have conflicting results about effectiveness.
In conclusion, the findings got in this study discovered the role of reactive oxygen species in the pathogenesis of mitochondrial DNA (mtDNA) mutations in male infertility. Where, both the ROS and mtDNA mutations are deem to be the main etiological factors in a variety of human diseases including male infertility.
This thesis is the first study on Egyptian population which demonstrated that the incidences and proportions of the mtDNAs with the ND1, ND2 and ATPase6 genes are positively associated with the spermatozoa motility and fertility. It was difficult to establish the effect of mitochondrial mutations in male infertility, where, the sample size was small and the study was only focused on the asthenozoospermic. But the results showed scientific indications evidenced that there might be an association between mitochondrial mutations and male infertility in some tested cases.