Almost 15% of couples suffer from infertility and the men account for 50% of infertility factors. The most prevalent reason of male infertility is due to problems in sperm production that include low number of sperms or low mobility of sperm and production of sperm with improperly function. Sperm cell needs ATP to perform its functions which provided by mitochondria. Presence of point mutations, polymorphisms and eliminations in mitochondrial DNA especially in D-loop region influence the ATP production and subsequently impair the performance of sperm.5>
Materials and methods
We collected 360 blood samples (24 azoospermia and 336 healthy controls) from men attending the infertility clinic at Research and Clinical Center for Infertility (Yazd, Iran). Genomic DNA was extracted from blood using salting-out procedure. To amplification of HV1 region, the universal primers of ONP98 F and ONP77 R and to amplification of HV2 region, universal primers of ONP38 F and ONP79 R were used.
Our data revealed that there were total 85 variations in HV1 and HV2 regions. From these variations, 78 mutations were previously reported and 7 mutations has not been reported yet. However, the D-loop G16129A and T16172C polymorphisms were associated with azoospemia (P < 0.05).
D-loop is contained two areas, namely, HV1 and HV2. The rate of mutation is higher in this area as a non-coding site. We found two polymorphisms (G16129A and T16172C) in HV1 region and then we compared the frequency of them between case and control groups. Our data revealed a significant differences between control and case groups (P<0.05). Since HV1 has an essential role in DNA replication therefore we suggest that G16129A and T16172C may change the DNA replication deficiency. The issue may change the copy number of mtDNA and mitochondrial function subsequently.