ETD

• assisted reproductive technology
• DNA fragmentation index
• lipus
• male infertility
• sperm motility
• ultrasound

Infertility is a growing global issue, with male factors accounting for approximately 30-50% of all cases. The causes of male infertility are multifactorial, commonly related to seminal disorders. When infertility cannot be treated, assisted reproductive technologies (ART) such as intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI) are employed. These techniques vary in complexity, invasiveness, and efficacy.
Among the parameters influencing fertilization success, both natural and assisted, sperm motility plays a key role, particularly total motile count and inseminating motile count. Numerous strategies have been investigated to enhance sperm motility and improve ART outcomes, but most have proven inconsistent, potentially harmful, or incompatible with clinical workflows due to procedural constraints.
In this work, we propose the use of low-intensity pulsed ultrasound (LIPUS), a safe and non-invasive technology, to induce sustained biological effects after short-term stimulation. The acoustic field generated by bulk waves exerts a controlled mechanical action on sperm cells, modulating their behaviour in a safe way.
Our results show an average 54% increase in curvilinear velocity one hour after stimulation, which remains significantly higher than control for up to three hours, and a threefold increase in the proportion of rapidly progressive sperm (from 9% to 24%). Biocompatibility was confirmed in terms of sperm vitality, morphology, and DNA fragmentation, indicating that ultrasound exposure does not compromise gamete integrity.
This method enables the pre-treatment of the entire sample, enhancing its properties prior to sperm selection. Such approach can offer a double benefit: increasing the number of sperm cells that are available post-processing and enhancing their motility to ultimately improve ART outcomes. The combination of biocompatibility, efficacy, procedural simplicity, and short duration suggests that ultrasound stimulation shows significant promise as an effective and clinically compatible complementary tool in assisted reproduction.