Perfluoro-octanoic acid impairs sperm motility through the alteration of plasma membrane.

Abstract

Perfluoroalkyl-substances (PFAS) are chemical additives considered harmful for humans. We recently showed that accumulation of perfluoro-octanoic acid (PFOA) in human semen of exposed subjects was associated with altered motility parameters of sperm cells, suggesting direct toxicity. To determine whether direct exposure of human spermatozoa to PFOA was associated to impairment of cell function. Spermatozoa isolated from semen samples of ten normozoospermic healthy donors were exposed up to 2h to PFOA, at concentrations from 0.1 to 10ng/mL. Viability and motility parameters were evaluated by Sperm Class Analyser. Cell respiratory function was assessed by both mitochondrial probe JC-1 and respiratory control ratio (RCR) determination. Sperm accumulation of PFOA was quantified by liquid chromatography-mass spectrometry. Expression of organic ion-transporters OATP1 and SLCO1B2 was assessed by immunofluorescence and respective role in PFOA accumulation was evaluated by either blockade with probenecid or membrane scavenging through β-cyclodextrin (β-CD). Plasma membrane fluidity and electrochemical potential (ΔΨp) were evaluated, respectively, with Merocyanine-540 and Di-3-ANEPPDHQ fluorescent probes. Compared to untreated controls, a threefold increase of the percentage of non-motile sperms was observed after 2h of exposure to PFOA regardless of the concentration of PFOA, whilst RCR was significantly reduced. Only scavenging with β-CD was effective in reducing PFOA accumulation, suggesting membrane involvement. Altered membrane fluidity, reduced ΔΨp and sperm motility loss associated with exposure to PFOA were reverted by β-CD treatment. PFOA alters human sperm motility through plasma-membrane disruption, an effect recovered by incubation with β-CD.