Perfluorooctane Sulfonate (PFOS) and Perfluorohexane Sulfonate (PFHxS) Alters Protein Phosphorylation, Increase ROS Levels and DNA Fragmentation during In Vitro Capacitation of Boar Spermatozoa

Abstract

Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) are toxic and bioaccumulative, included in the Stockholm Convention’s list as persistent organic pollutants. Due to their toxicity, worldwide distribution, and lack of information in spermatozoa physiology during pre-fertilization processes, the present study seeks to analyze the toxic effects and possible alterations caused by the presence of these compounds in boar sperm during the in vitro capacitation. The spermatozoa capacitation was performed in supplemented TALP-Hepes media and mean lethal concentration values of 460.55 μM for PFOS, and 1930.60 μM for PFHxS were obtained. Results by chlortetracycline staining showed that intracellular Ca2+ patterns bound to membrane proteins were scarcely affected by PFOS. The spontaneous acrosome reaction determined by FITC-PNA was significantly reduced by PFOS and slightly increased by PFHxS. Both toxic compounds significantly alter the normal capacitation process from 30 min of exposure. An increase in ROS production was observed by flow cytometry and considerable DNA fragmentation by the comet assay. The immunocytochemistry showed a decrease of tyrosine phosphorylation in proteins of the equatorial and acrosomal zone of the spermatozoa head. In conclusion, PFOS and PFHxS have toxic effects on the sperm, causing mortality and altering vital parameters for proper sperm capacitation.

Toxic effects of per- and polyfluoroalkyl substances on sperm: Epidemiological and experimental evidence

“…Our previous study showed that incubation with PFOA in vitro compromised progesterone-induced acrosome reaction and viscous medium penetration in human sperm ( 43 ). Similarly, in vitro exposure to PFOA and PFOS decreased the number of capacitated spermatozoa and hindered progesterone-induced acrosomal reaction in boar spermatozoa ( 45 , 46 ).…”

How Per- and Poly-Fluoroalkyl Substances Affect Gamete Viability and Fertilization Capability: Insights from the Literature

“…The blood–testis barrier is crossed by PFAS, allowing for direct interaction with sperm [ 18 , 57 , 58 ]. PFOS and PFOA exposure can impact semen quality by coiling sperm tails, impacting the crucial component of sperm motility through the female reproductive tract [ 12 ]. Studies point to decreased sex hormone-binding globulin (SHBG), FSH, and testosterone after increased exposure levels to PFOA and PFOS [ 12 , 31 ].…”

“…PFAS are extremely resistant to degradation, both environmentally and metabolically. Additionally, PFAS are extremely thermally and chemically stable [ 1 , 12 ]. Primarily, PFAS are excreted by the body through urine, with other routes of elimination being breast milk and menstrual blood [ 13 , 14 ].…”

A Sea Anemone Lebrunia neglecta Venom Fraction Decreases Boar Sperm Cells Capacitation: Possible Involvement of HVA Calcium Channels

“…Slides were observed under a fluorescence microscope (Olympus BX51, Japan) at 495 nm UV epifluorescence and 400× magnification. Capacitation was determined as follows: non-capacitated spermatozoa presented fluorescence throughout the head and capacitated spermatozoa showed intense fluorescence in the equatorial and acrosomal zone [41].…”