Increased F2-isoprostane levels in semen and immunolocalization of the 8-iso prostaglandin F2α in spermatozoa from infertile patients with varicocele

Polyunsaturated fatty acid damages lead to alterations in sperm function. This study aimed to investigate the involvement of F2-isoprostanes (F2-IsoPs), oxidized lipid products from arachidonic acid, in sperm quality impairment. For this purpose, F2-IsoP levels in semen and F2-IsoP localization in spermatozoa were explored in infertile subjects affected by idiopathic infertility or varicocele, as well as in fertile men. As compared to fertile men, in the idiopathic infertility and varicocele groups, sperm concentration, motility, morphology, viability, and fertility index were significantly lower and the mean scores concerning sperm apoptosis, necrosis, and immaturity were significantly higher. The idiopathic infertile group showed a reduction in sperm motility and fertility index, as well as an increase of apoptosis and necrosis percentages, in comparison to the varicocele group. The varicocele group showed the highest levels of F2-IsoPs, a significant increase of sperm immaturity, and a significant correlation between F2-IsoP levels and sperm immaturity. 8-Iso Prostaglandin F2α, biomarker of in vivo F2-IsoP, was clearly localized in sperm midpiece and cytoplasmic residues. Data show that F2-IsoP formation is relevant in semen and sperm from infertile patients with varicocele and high percentage of immaturity, suggesting that a correct fatty acid integrity is needed for sperm maturation.