Effects of dioxins on animal spermatogenesis: A state-of-the-art review

Abstract

The male reproductive system is especially affected by dioxins, a group of persistent environmental pollutants, resulting in irreversible abnormalities including effects on sexual function and fertility in adult males and possibly on the development of male offspring. The reproductive toxicity caused by dioxins is mostly mediated by an aryl hydrocarbon receptor (AhR). In animals, spermatogenesis is a highly sensitive and dynamic process that includes proliferation and maturation of germ cells. Spermatogenesis is subject to multiple endogenous and exogenous regulatory factors, including a wide range of environmental toxicants such as dioxins. This review discusses the toxicological effects of dioxins on spermatogenesis and their relevance to male infertility. After a detailed categorization of the environmental contaminants affecting the spermatogenesis, the exposure pathways and bioavailability of dioxins in animals was briefly reviewed. The effects of dioxins on spermatogenesis are then outlined in detail. The endocrine-disrupting effects of dioxins in animals and humans are discussed with a particular focus on their effects on the expression of spermatogenesis-related genes. Finally, the impacts of dioxins on the ratio of X and Y chromosomes, the status of serum sex hormones, the quality and fertility of sperm, and the transgenerational effects of dioxins on male reproduction are reviewed.

Bioaccumulation and Male Reproductive Toxicity of the New Brominated Flame Retardant Tetrabromobisphenol A-Bis(2,3-dibromo-2-methylpropyl ether) in Comparison with Hexabromocyclododecane

“…On PND 7, the mean HBCD concentration was 66 ng/g (lipid) in HBCD-treated mouse livers, while the concentrations of TBBPA-DBMPE were 109 and 882 ng/g (lipid) in the TD-50 and TD-1000 groups, respectively (Figure ). The data show that TBBPA-DBMPE can transfer from dams to pups through breast milk, like HBCD and other POPs. − Compared with the data on PND 7, their burdens in livers on PND 56 remarkably increased, with 246 ng/g HBCD in the HB-50 group and 201 and 1981 ng/g TBBPA-DBMPE in the TD-50 and TD-1000 groups, respectively. These observations demonstrate the bioaccumulation of TBBPA-DBMPE with time.…”

Comment on “Maternal Exposure to Per- and Polyfluoroalkyl Substances (PFAS) and Male Reproductive Function in Young Adulthood: Combined Exposure to Seven PFAS”

“…These data reinforce that associations between PFAS levels and parameters of semen quality require careful interpretation with respect to possible causal relationships and the critical window of exposure. The current evidence, including that from animal studies, 5 suggests that the observed diminished semen quality may also be attributable to dioxins that co-occur with PFAS, either singly or in the mixture, or may be related to lifestyle factors altogether. 11 …”

“… 2 Dioxins, in particular, have been suspected agents ever since results began emerging from studies of cohorts exposed to very high levels of 2,3,7,8-tetrachlorodibenzo- -dioxin following the 1976 Seveso accident 3 , 4 ; a causal relationship is supported by animal data. 5 In 2018, the European Food Safety Authority used data from a study of high ambient exposure in a Russian industrial city 6 to derive a tolerable weekly intake for dioxins below mean consumption levels observed in several countries. 7 …”

Impact of dioxins on reproductive health in female mammals

“…As a prototype of halogenated aromatic compounds, TCDD is frequently employed to illustrate the toxicological effects of dioxins on organisms. Numerous studies have reported that TCDD induces a range of toxicological effects, encompassing reproductive, developmental, and carcinogenic impacts in both exposed individuals and a diverse array of experimental animal models ( White and Birnbaum, 2009 ; Faiad et al, 2022 ; Aldeli et al, 2023 ; Faiad et al, 2023 ; Hammoudeh et al, 2023 ).…”