Addition of Chlorogenic Acid to Human Semen: Effects on Sperm Motility, DNA Integrity, Oxidative Stress, and Nrf2 Expression

This study evaluated the effects of chlorogenic acid (CGA) on human semen and on oxidative stress (OS) induced in vitro in human spermatozoa. After the treatment of the basal semen with 100 µM CGA, rapid and slow sperm progressive motility were evaluated and seminal F₂-Isoprostanes (F₂-IsoPs), a marker of OS, were quantified by ELISA. In a second set of experiments, semen was treated with 100 µM CGA, 1 mM H₂O₂ to induce OS, or H₂O₂+CGA; untreated samples were used as controls. Then, sperm motility, DNA integrity by the acridine orange test, F₂-IsoPs and <i>Nrf2</i> mRNA expression by RT-PCR were quantified. In CGA-treated specimens, rapid progressive sperm motility was increased (<i>p</i> < 0.01) and F₂-IsoP levels decreased (<i>p</i> < 0.001) versus controls. The increase of F₂-IsoP levels and DNA damage and the decrease of sperm motility after H₂O₂ treatment was reversed in the presence of CGA, which upregulated <i>Nrf2</i> mRNA expression. These findings contributed to clarifying CGA's antioxidant activity and highlighted the positive impact of CGA on sperm progressive motility, suggesting also a possible mechanism of action based on the Nrf2 pathway. CGA can be useful during human semen handling procedures in the laboratory and in optimizing the recovery of motile spermatozoa through selection techniques during assisted reproductive technology protocols.