Effects of chronic exposure to nonylphenol at environmental concentration on thyroid function and thyroid hyperplasia disease in male rats

Bioaccumulation and in vivo tracking of radiolabeled 4-nonylphenol in mice

4-Nonylphenol (4NP) is concerning due to its growing presence and endocrine-disrupting nature, raising concerns about its impact on health. In this study 124I-labeled 4NP was synthesized for in vivo tracing. Positron emission tomography imaging and biodistribution studies showed significant accumulation in various tissues after oral or intraperitoneal administration, emphasizing its intricate distribution and potential long-term effects, crucial for future risk assessments.

Myocardial fibrosis induced by nonylphenol and its regulatory effect on the TGF-β1/LIMK1 signaling pathway

OBJECTIVE

We here explored whether perinatal nonylphenol (NP) exposure causes myocardial fibrosis (MF) during adulthood in offspring rats and determined the role of the TGF-β1/LIMK1 signaling pathway in NP-induced fibrosis in cardiac fibroblasts (CFs).

METHODS AND RESULTS

Histopathology revealed increased collagen deposition and altered fiber arrangement in the NP and isoproterenol hydrochloride (ISO) groups compared with the blank group. Systolic and diastolic functions were impaired. Western blotting and qRT-PCR demonstrated that the expression of central myofibrosis-related proteins (collagens Ι and ΙΙΙ, MMP2, MMP9, TGF-β1, α-SMA, IL-1β, and TGF-β1) and genes (Collagen Ι, Collagen ΙΙΙ, TGF-β1, and α-SMA mRNA) was upregulated in the NP and ISO groups compared with the blank group. The mRNA-seq analysis indicated differential expression of TGF-β1 signaling pathway-associated genes and proteins. Fibrosis-related protein and gene expression increased in the CFs stimulated with the recombinant human TGF-β1 and NP, which was consistent with the results of animal experiments. According to the immunofluorescence analysis and western blotting, NP exposure activated the TGF-β1/LIMK1 signaling pathway whose action mechanism in NP-induced CFs was further validated using the LIMK1 inhibitor (BMS-5). The inhibitor modulated the TGF-β1/LIMK1 signaling pathway and suppressed the NP-induced increase in fibrosis-related protein expression in the CFs. Thus, the aforementioned pathway is involved in NP-induced fibrosis.

CONCLUSION

We here provide the first evidence that perinatal NP exposure causes myocardial fibrosis in growing male rat pups and reveal the molecular mechanism and functional role of the TGF-β1/LIMK1 signaling pathway in this process.

Association between prenatal exposure to alkylphenols and intelligence quotient among preschool children: sex-specific effects

BACKGROUND

While prenatal exposure to alkylphenols (APs) has been demonstrated to be associated with neurodevelopmental impairments in animals, the evidence from epidemiological studies remains limited and inconclusive. This study aimed to explore the link between AP exposure during pregnancy and the intelligence quotient (IQ) of preschool children.

METHODS

A total of 221 mother-child pairs from the Guangxi Zhuang Birth Cohort were recruited. Nonylphenol (NP), 4-tert-octylphenol (4-T-OP), 4-n-nonylphenol (4-N-NP), and 4-n-octylphenol were measured in maternal serum in early pregnancy. Childhood IQ was evaluated by the Fourth Edition of Wechsler Preschool and Primary Scale of the Intelligence at 3 to 6 years of age. The impact of APs on childhood IQ were evaluated by generalized linear models (GLMs), restricted cubic spline (RCS), and Bayesian kernel machine regression (BKMR).

RESULTS

In GLMs, prenatal exposure to NP and the second tertile of 4-T-OP exhibited an inverse association with full-scale IQ (FSIQ) (β = -2.38; 95% CI: -4.59, -0.16) and working memory index (WMI) (β = -5.24; 95% CI: -9.58, -0.89), respectively. Prenatal exposure to the third tertile of 4-N-NP showed a positive association with the fluid reasoning index (β = 4.95; 95% CI: 1.14, 8.77) in total children, as well as in girls when stratified by sex. A U-shaped relationship between maternal 4-T-OP and WMI was noted in total children and girls by RCS (all P nonlinear < 0.05). The combined effect primarily driven by NP, of maternal AP mixtures at concentrations above the 50th percentile exhibited an inverse trend on FSIQ in total children and girls in BKMR.

CONCLUSIONS

Prenatal exposure to various APs affects IQ in preschool children, and there may be nonmonotonic and sex-specific effects. Further investigation across the population is required to elucidate the potential neurotoxic effects of APs.

The environmental burden on endocrine neoplasia: a review on the documented impact of endocrine disrupting chemicals

INTRODUCTION

Endocrine-disrupting chemicals (EDCs) have gained more importance in the past decade, mostly due to their role in the pathogenesis of disease, especially in carcinogenesis. However, there is limited literature on the environmental burden on some of the less common endocrine neoplasia.

AREAS COVERED

This review focuses on both observational and experimental studies linking exposure to EDCs and endocrine neoplasia specifically pituitary, thyroid, adrenal and neuroendocrine tumors. Following PRISMA guidelines, a search of English peer-reviewed literature was performed using Medline and Google Scholar, giving preference to recent publications.

EXPERT OPINION

Exposure to EDC occurs not only in the household but also at work, whether it is in the office, factory, or farm and during transport from one location to another. Many studies have evaluated the effect of single environmental agents; however, humans are rarely exposed to only one EDC. Different EDCs and different levels of exposure may interact together to provide either a synergistic and/or an antagonistic disruption on human health, and hence a complex mechanism to elucidate. The ultimate adverse effect is difficult to predict, as it is not only influenced by the degree of exposure, but also by genetics, lifestyle, comorbidities, and other stressors.

Mechanism of nonylphenol induced gastric inflammation through NF-κB/NLRP3 signaling pathway

Studies have found that the intake of environmental endocrine disruptors was positively correlated with the occurrence of gastric diseases. The aim of this study was to determine whether nonylphenol (NP) exposure can induce gastric inflammation and whether its mechanism was related to NF-κB/NLRP3 signaling pathway. In vivo, male SD rats were randomly divided into 4 groups (12 rats/group): control group (corn oil), NP low (0.4mg/kg), medium (4mg/kg), and high (40mg/kg) dose groups. After 33 weeks of NP chronic exposure, it was found pathological changes in gastric tissues, increase the release of inflammatory factors, and effects expressions of genes related to the NF-κB/NLRP3 signaling pathway. In vitro, the GES-1 cell experiments, which included four groups: control (0 µmol/L NP), L (2.5 µmol/L NP), M (40 µmol/L NP), and H (60 µmol/L NP), confirmed that NP increased the release of inflammatory factors in the cells, and up-regulated the expression of proteins related to NF-κB/NLRP3 signaling pathway. Furthermore, when pyrrolidinedithiocarbamate ammonium (PDTC) blocked the NF-κB signaling pathway, it was found that the expression of related proteins in the NF-κB/NLRP3 signaling pathway was decreased, and the release of inflammatory factors in GES-1 cells caused by NP was also attenuated. The results of this study indicated that NP can induce inflammation in the stomach in vivo and in vitro, and its mechanism was related to the NF-κB/NLRP3 signaling pathway. These findings provided a new perspective on the mechanism of inflammatory response induced by exposure to environmental endocrine disruptors. Also, these findings indicated that therapeutic strategies for the NF-κB/NLRP3 signaling pathway may be new methods to treat inflammatory diseases.

Nonylphenol induces anxiety-like behavior in rats by regulating BDNF/TrkB/CREB signal network

This study aimed to verify whether chronic exposure to nonylphenol (NP) induces anxiety behavior in rats and explored NP's regulatory effect on the BDNF/TrkB/CREB signal network in vitro. Anxiety-like behavior was assessed by elevated plus-maze and light-dark box tests. The residence time in the closed arm increased with NP dose (4, 40 mg/kg) and exposure time (3 and 6 months) (P < 0.05). The hippocampal neurons in the medium dose (M-NP, 4 mg/kg) and high dose (H-NP, 40 mg/kg) groups showed disorderly arrangement, cell swelling, and nuclear pyknosis/necrosis. The protein/mRNA expressions of BDNF/TrkB/CREB in the H-NP group decreased, and the decrease was more significant at 6 months (P < 0.05). Both, NP exposure and BDNF knockdown, increase the number of apoptotic cells (P ＜0.001). NP downregulated the proteins/mRNA expressions of BDNF/TrkB/CREB, and the trend was consistent with the BDNF silence group. Chronic exposure to NP could induce anxiety-like behavior in rats and reduce the expression of key proteins/genes in the BDNF/TrkB/CREB signaling network.

Effect of nonylphenol on the colonic mucosa in rats and intervention with zinc-selenium green tea (Camellia sinensis)

To investigate the effect of nonylphenol (NP) exposure on the colonic mucosa in rats, and the protective effects of Guizhou zinc-selenium tea (Zn-Se tea) on the damage induced by NP, sixty Sprague-Dawley rats were randomly divided into 6 groups (n = 10 in each group): control group (corn oil), and rats gavaged with NP at the doses of 0.4 mg/kg/d (Low NP group), 4 mg/kg/d (Medium NP group), 40 mg/kg/d (High NP group), and 40 mg/kg NP combined with green tea group at the doses of 0.2 g/ml (NP + GT group) and 0.2 g/ml Zn-Se tea group (NP + ZST group). NP at 40 mg/kg/d was administered to the tea groups for 3 months, followed by NP + green tea and NP + Zn-Se tea for 4 months, and the rest of the groups were gavaged for 7 months. With the increase of NP concentration, NP accumulation in colon gradually increased (P < 0.05), colonic villi shortened, tight junctions between cells widened, intestinal integrity was impaired, and goblet cells, intraepithelial lymphocytes and mast cells were significantly lower in NP high-dose group than in control group (P < 0.05). Meanwhile, the protein expression of Caspase-1, IL-1β and Pro-IL-1β in NP high-dose group was significantly higher than that in control group (P < 0.05). Zn-Se tea increased the number of goblet cells in colon and decreased the accumulation of NP in colon (P < 0.05); Zn-Se tea and common green tea decreased the expression of Caspase-1 and Pro-IL-1β protein (P < 0.05). NP exposure can destroy intestinal morphology, reduce the number of intestinal immune cells, reduce intestinal immunity and increase the release of inflammatory factors; Guizhou Zn-Se tea has a certain protective effect on colon damage caused by NP.