RESUMO
Male infertility is a great matter of concern as out of 15% of infertile couples in the reproductive age, about 40% are contributed by male factors alone. For DNA condensation during spermatogenesis, constrained DNA nicking is required, which if increased beyond certain level results in infertility in men. High sperm DNA Fragmentation (SDF) majorly contributes to male infertility and its association with regards to poor natural conception and assisted reproductive technology (ART) outcomes is equivocal. Apoptosis, protamination failure and the excess of reactive oxygen species (ROS) are considered to be the main causes of SDF. It's testing came into existence because of the limitations of the conventional methods in explaining infertility in normozoospermic infertile individuals. Over the past 25 years, SDF's several testing strategies have been proposed to diagnose the aetiology of infertility. Various treatments combined with sperm selection techniques are being used alone or in combination to reduce DNA fragmentation index (DFI) and obtain spermatozoa with high quality chromatin for assisted reproduction. This review summarises SDF's main causes, its impact on fertility and clinical outcomes in assisted reproduction, the need to perform test, testing procedures, and the treatment strategies.
Assuntos
Fragmentação do DNA , Infertilidade Masculina , Espermatozoides , Humanos , Masculino , Infertilidade Masculina/terapia , Infertilidade Masculina/diagnóstico , Infertilidade Masculina/etiologia , Técnicas de Reprodução AssistidaRESUMO
Oocyte retrieval, oocyte denudation, and embryo transfer are crucial processes during assisted reproduction technology (ART). Air quality in the ART laboratory, temperature, pH of the media used and the time interval between oocyte retrieval and insemination are all critical factors. Anesthesia is required for oocyte retrieval, however, evidence regarding the potential impact of different methods (general anesthesia, conscious sedation, and local anesthesia) on the clinical outcomes is unclear. The optimal timing of oocyte denudation following retrieval has not been established. Regarding the mechanical denudation process, there is a lack of evidence to demonstrate the safest minimum inner diameter of denuding pipettes used to complete the removal of granulosa cells surrounding the oocytes. During embryo transfer, many clinics worldwide flush the catheter before embryo loading, in an attempt to potentially rinse off any toxic agents; however, there is insufficient evidence to show that flushing the embryo transfer catheter before loading increases the success of ART outcome. Considering the serious gaps in knowledge in ART practice, the aim of this review is to provide an updated overview of the current knowledge regarding the various steps and techniques involved in oocyte retrieval, oocyte denudation, and embryo loading for transfer.