P-084 Oral antioxidant supplementation ameliorates the deleterious effects of plasticizers Bisphenol AF (BPAF) and Dibutyl Phthalate (DBP) on mouse sperm DNA integrity
Authors: Drevet J , Hug E , Villeneuve P , Bravard S , Damon-Soubeyrand C , Moazamian A , Geurtsen R , Aitken J R , Saez F , Gharagozloo P 
Published: June 2023

Abstract

Study question
Do common chemicals in plastic, BPAF and DBP, negatively impact sperm parameters and DNA integrity, and can oral antioxidant supplementation mitigate their impact?

Summary answer
Short-term, low-dose exposure to BPAF or DBP did not impact testicular/epididymal histology but caudal epididymal sperm parameters, particularly DNA integrity was significantly compromised.

What is known already
Plasticizers are among the most commonly produced chemicals worldwide with 90% of people showing detectable levels in their urine. As endocrine disruptors (EDCs), they act as estrogen mimetics but can also induce oxidative stress and form DNA adducts. Numerous studies have linked exposure to EDCs to impaired spermatogenesis, sperm DNA damage and male infertility. Limited studies suggest antioxidants may alleviate the reproductive toxicity of EDCs. This study measured the effects of short-term exposures to two common environmental EDCs (BPAF & DBP) on the post-testicular compartment epididymis and investigate the efficacy of an oral antioxidant supplement to safeguard sperm DNA integrity.

Study design, size, duration
Adult male CD1 mice were exposed to low doses (50mg/kg) of BPAF or DBP with or without co-administration of antioxidant supplementation (Fertilix®) for 14 days and evaluated after euthanasia.

Participants/materials, setting, methods
All experiments were performed at the University Clermont Auvergne, Clermont-Ferrand, France. Mice were supplemented with BPAF, DBP or/and Fertilix® in their drinking water. The results of exposure of males were evaluated against controls and included: testicular and epididymal histology, epididymal ROS status via 4-HNE levels in caput protein extracts, general semen parameters: (count, motility, viability, acrosome integrity), sperm nuclear/DNA parameters [decondensation (Toluidine blue stain), fragmentation (TUNEL test), oxidation (8-OHdG residue level)].

Main results and the role of chance
The histology of the testis and epididymis was unaffected by the exposure conditions used. An oxidative stress situation was evident by the EDC exposures, demonstrated by increased level of 4-HNE adducts in the epididymal caput protein extracts. Viability, total and progressive motility, and acrosome integrity of caudal epididymal spermatozoa remained unaltered in exposed animals compared with controls. Exposure to BPAF but not DBP significantly decreased sperm count. Sperm nuclear/DNA integrity assessed by the percentages of sperm with decondensed and oxidized nuclei was significantly increased in EDC-exposed animals. Sperm DNA fragmentation did not significantly increase in any group of exposed animals. Co-administration with Fertilix® significantly corrected the defective sperm parameters (nuclear decondensation and DNA base oxidation) with the exception of sperm count which did not return to control levels in BPAF+ Fertilix® treated animals. These data confirm that even at low doses and short-term exposures, epididymal spermatozoa are susceptible to DNA damage induced by environmental ROS-generating EDCs, confirming its association with male infertility.

Limitations, reasons for caution
The translation of these findings to humans needs to be confirmed, although the nuclear compartment of human sperm is more susceptible to oxidative alterations than that of the mouse.

Wider implications of the findings
These data demonstrate the susceptibility of post-testicular sperm cells to common environmental chemicals. They also support the use of appropriate antioxidant supplementation as an effective therapeutic choice for individuals with multiple exposures to environmental stressors such as ROS-generating EDCs.

Trial registration number
not applicable