Associations of Sperm mtDNA copy number, DNA fragmentation index, and reactive oxygen species with clinical outcomes in ART treatments

Abstract Background Except for sperm parameters (sperm concentration, motility, and morphology), sperm mitochondria DNA copy number (mtDNA-CN), DNA fragmentation index (DFI), and reactive oxygen species (ROS) content are essential characteristics for sperm function. However, the roles of these measurements in embryo development and pregnancy outcomes are still unclear. Methods Semen samples of 402 participants were collected. Sperm parameters, including sperm morphology, concentration, and motility, were analyzed by a computer-assisted sperm analysis system. MtDNA-CN, DFI, and ROS levels were measured using remained sperms through quantitative polymerase chain reaction method, sperm chromatin structure assay and Reactive Oxygen Species Assay Kit, respectively. The assisted reproductive technology (ART) treatments, including in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), were performed in 126 couples of these participants. Results In 402 semen samples, elevated mtDNA-CN and DFI were associated with poor seminal quality. In 126 couples conducted ART, only mtDNA-CN was negatively correlated with fertilization rate in ART cases. However, it was not significant after adjusting male age, female age, seminal quality, and ART strategy. With regard to pregnancy outcomes, none of sperm mtDNA-CN, ROS and DFI was associated with clinical pregnancy rate in 79 cases transferred embryos. Conclusions Increased mtDNA-CN and DFI in sperms jointly contributed to poor seminal quality. However, none of sperm mtDNA-CN, ROS/MS and DFI were associated with clinical outcomes in ART.