Inter-Day Variability of Metabolites of DEHP and DnBP in Human Urine-Comparability of the Results of Longitudinal Studies with a Cross-Sectional Study

Prenatal DEHP exposure induces lifelong testicular toxicity by continuously interfering with steroidogenic gene expression

Background

Epidemiologic studies suggested the association between prenatal di-(2-ethylhexyl) phthalate (DEHP) exposure and disorders of sex development (DSD), adult male disorders, and reproductive aging. Inhibiting testosterone synthesis by interfering with steroidogenic gene expression induces testicular toxicity, however, whether prenatal DEHP exposure induces testicular toxicity through this mechanism remains uncertain.

Methods

C57BL/6JGpt male mice underwent different doses (0, 100, 500, 1,000 mg/kg) of prenatal DEHP exposure during gestational day 10 to delivery day, the testicular toxicity (genital development, testosterone, semen quality, and morphology of testis tissue) in the neonatal, post-puberal and middle-aged stages was observed, and the steroidogenic gene (Lhcgr, Star, Cyp11a1, Cyp17a1, Hsd17b3, and Hsd3b2) expression was analyzed by quantitative polymerase chain reaction (qPCR) and Western blot (WB). The interference of steroidogenic gene expression in TM3 cells after mono-(2-ethylhexyl) phthalate (MEHP) exposure was also explored for verification.

Results

Prenatal DEHP exposure induced immediate testicular injury in the neonatal stage [reduced anogenital distance (AGD) and intratesticular testosterone], DSD in the post-puberal stage (poor genital development), and reproductive aging in the middle-aged stage (obesity, reduced testosterone and semen quality, and atrophic seminiferous tubules), especially in the high dose. Prenatal DEHP exposure continuously interfered with steroidogenic gene expression (Hsd3b2, Hsd17b3) in RNA and protein levels. MEHP inhibited testosterone synthesis of TM3 cells by interfering with steroidogenic gene expression (Hsd3b2, Hsd17b3) in RNA and protein levels.

Conclusions

Prenatal DEHP exposure induces lifelong testicular toxicity by continuously interfering with steroidogenic gene expression, thus indicating the association between prenatal exposure and DSD, adult male disorders, and reproductive aging.

Distribution of Micro-Nano PS, DEHP, and/or MEHP in Mice and Nerve Cell Models In Vitro after Exposure to Micro-Nano PS and DEHP

Polystyrene (PS) and di-(2-ethylhexyl) phthalate (DEHP) exist widely in the environment. However, their distribution in organisms remains unclear. We used three sizes (50 nm, 500 nm, and 5 μm) of PS and DEHP to study the distribution and accumulation of PS, DEHP, and mono(2-ethylhexyl) phthalate (MEHP) in mice and nerve cell models (HT22 and BV2 cells) and their potential toxicity. Results showed that PS entered the blood of mice, and the distribution of different particle sizes in different tissues was different. After the combined exposure to PS and DEHP, PS carried DEHP, which significantly increased the DEHP content and MEHP content and the highest content of MEHP was in the brain. With the decrease in PS particle size, the contents of PS, DEHP, and MEHP in the body increased. The levels of inflammatory factors were increased in the serum of the PS or/and DEHP group. In addition, 50 nm polystyrene can carry MEHP into nerve cells. These results suggest for the first time that PS and DEHP combined exposure can induce systemic inflammation, and the brain is an important target organ of PS and DEHP combined exposure. This study may serve as a reference for further evaluation of the neurotoxicity induced by combined exposure to PS and DEHP.

Adverse cardiovascular effects and potential molecular mechanisms of DEHP and its metabolites-A review

Currently, cardiovascular disease (CVD) is a health hazard that is associated with progressive deterioration upon exposure to environmental pollutants. Di(2-ethylhexyl) phthalate (DEHP) has been one of the focuses of emerging concern due to its ubiquitous nature and its toxicity to the cardiovascular (CV) system. DEHP has been noted as a causative risk factor or a risk indicator for the initiation and augment of CVDs. DEHP represents a precursor that contributes to the pathogenesis of CVDs through its active metabolites, which mainly include mono (2-ethylhexyl) phthalate (MEHP). Herein, we systematically presented the association between DEHP and its metabolites and adverse CV outcomes and discussed the corresponding effects, underlying mechanisms and possibly interventions. Epidemiological and experimental evidence has suggested that DEHP and its metabolites have significant impacts on processes and factors involved in CVD, such as cardiac developmental toxicity, cardiac injury and apoptosis, cardiac arrhythmogenesis, cardiac metabolic disorders, vascular structural damage, atherogenesis, coronary heart disease and hypertension. DNA methylation, PPAR-related pathways, oxidative stress and inflammation, Ca²⁺ homeostasis disturbance may pinpoint the relevant mechanisms. The preventive and therapeutic measures are potentially related with P-glycoprotein, heat-shock proteins, some antioxidants, curcumin, apigenin, β-thujaplicin, glucagon-like peptide-1 receptor agonists and Ang-converting enzyme inhibitors and so on. Promisingly, future investigations should aid in thoroughly assessing the causal relationship and molecular interactions between CVD and DEHP and its metabolites and explore feasible prevention and treatment measures accordingly.

Critical analysis of peptidoglycan structure of Lactobacillus acidophilus for phthalate removal

Our previous studies have shown that lactic acid bacteria (LABs) can bind and remove di-n-butyl phthalate (DBP), diethyl phthalate, and dioctyl phthalate; three ubiquitous environmental phthalate contaminants. In this study, Lactobacillus acidophilus NCFM was chosen to study the DBP binding mechanism. We found that the three-dimensional structure of the bacterial cell wall, including the carbohydrates and proteins, was essential for DBP adsorption. Peptidoglycan was the main binding component in the cell wall (80.71%), and binding sites exposed to DBP were C-N, N-H, O-H, and C-O bonds. Molecular dynamic (MD) studies demonstrated that hydrophobic interaction plays an important role in DBP adsorption, the chemical sites that influenced the binding in the peptidoglycan model were O2, O3>N1, N2, N3>O1, O4, and the form of adsorption force included hydrogen bonding force, electrostatic force, and van der Waals forces. These theoretical data from the MD simulation were consistent with the experimental results in terms of the ability of this bacterium to bind DBP, so the MD simulation proposed a new way to investigate the mechanisms of phthalate binding to LABs.