Adverse effects of 4-tert-octylphenol on the production of oxytocin and hCG in pregnant rats

Murine Models and Research Progress on Dysmenorrhea

Dysmenorrhea is a prevalent gynecological disease among women at reproductive age. It is classified as the primary dysmenorrhea and the secondary dysmenorrhea according to the etiology. The primary dysmenorrhea is caused by uterine hypercontraction without any identifiable pelvic lesions, while the secondary dysmenorrhea is incurred by gynecological disorder with pelvic organic lesions. However, the underlying mechanism of dysmenorrhea is not completely clear. Animal models of dysmenorrhea, especially mouse and rat model, are helpful to explore the pathophysiological mechanism of dysmenorrhea, clarify the therapeutic effect of compounds, and guide clinical treatment. The murine model of primary dysmenorrhea is commonly induced by oxytocin or prostaglandin F_2α, while the secondary dysmenorrhea murine model was further created by injecting oxytocin on the basis of the established primary disease model. This review summarizes the current progress of dysmenorrhea models in rodent, including experimental methods, corresponding evaluation indexes, and the advantages and disadvantages of various murine dysmenorrhea models, in order to provide a reference for the selection of murine dysmenorrhea models and the further study of the pathophysiological mechanism of dysmenorrhea.

Environmental Water Pollution, Endocrine Interference and Ecotoxicity of 4-tert-Octylphenol: A Review

4-tert-Octylphenol is a degradation product of non-ionic surfactants alkylphenol polyethoxylates as well as raw material for a number of industrial applications. It is a multimedia compound having been detected in all environmental compartments such as indoor air and surface waters. The pollutant is biodegradable, but certain degradation products are more toxic than the parent compound. Newer removal techniques from environmental waters have been presented, but they still require development for large-scale applications. Wastewater treatment by plant enzymes such as peroxidases offers promise in total removal of 4-tert-octylphenol leaving less toxic degradation products. The pollutant's endocrine interference has been well reported but more in oestrogens than in any other signalling pathways through which it is believed to exert toxicity on human and wildlife. In this paper we carried out a review of the activities of this pollutant in environmental waters, endocrine interference and relevance to its toxicities and concluded that inadequate knowledge of its endocrine activities impedes understanding of its toxicity which may frustrate current efforts at ridding the compound from the environment.

Metabolomics Reveals Metabolic Changes Caused by Low-Dose 4-Tert-Octylphenol in Mice Liver

Background: Humans are constantly exposed to low concentrations of 4-tert-octylphenol (OP). However, studies investigating the effects of low-dose OP on the liver are scarce, and the mechanism of these effects has not been thoroughly elucidated to date. Methods: Adult male institute of cancer research (ICR) mice were exposed to low-dose OP (0, 0.01 and 1 μg/kg/day) for 7 consecutive days. Weights of mice were recorded daily during the experiment. Blood serum levels of OP, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined, and haematoxylin-eosin (HE) staining of the liver was performed. We applied an integrated metabolomic and enzyme gene expression analysis to investigate liver metabolic changes, and the gene expression of related metabolic enzymes was determined by real-time PCR and ELISA. Results: OP in blood serum was increased after OP exposure, while body weights of mice were unchanged. Liver weight and its organ coefficient were decreased significantly in the OP (1 μg/kg/day) group, but ALT and AST, as well as the HE staining results, were unchanged after OP treatment. The levels of cytidine, uridine, purine and N-acetylglutamine were increased significantly, and the level of vitamin B6 was decreased significantly in mice treated with OP (1 μg/kg/day). The mRNA and protein levels of Cda and Shmt1 were both increased significantly in OP (1 μg/kg/day)-treated mice. Conclusions: Through metabolomic analysis, our study firstly found that pyrimidine and purine synthesis were promoted and that N-acetylglutamine was upregulated after low-dose OP treatment, indicating that the treatment disturbed nucleic acid and amino acid metabolism in mice liver.

Effects of cigarette smoke extracts on cell cycle, cell migration and endocrine activity in human placental cells

Maternal smoking during pregnancy is known to be related to adverse pregnancy results associated with trophoblast proliferation and cell cycle progression. Moreover, many previous studies have shown that cigarette smoke is correlated with human chorionic gonadotropin beta (hCG-β) subunit produced from syncytiotrophoblasts during pregnancy. Thus, we further investigated whether cigarette smoke extract (CSE) affects the cell proliferation, migration and endocrine hormone activity of JEG-3 human placental cancer cells. JEG-3 cell proliferation was significantly reduced by all CSEs in a concentration-dependent manner. Moreover, CSEs decreased proliferating cell nuclear antigen (PCNA) levels in JEG-3 cells in Western blot. Increased migration or invasion ability of JEG-3 cells following CSE treatment was also confirmed by a scratch or fibronectin invasion assay in vitro. Additionally, protein levels of E-cadherin as an epithelial maker were down-regulated, while the mesenchymal markers N-cadherin, snail and slug were up-regulated in a time-dependent manner. The metastasis marker, cathepsin D, was also down-regulated by CSE. Finally, CSEs significantly reduced the expression of hCG-β protein in JEG-3 cells. Overall, these results indicate that exposure of placental cells to CSE deregulates the cell cycle by altering the expression of cell cycle-related proteins and stimulates cell metastatic ability by altering EMT markers and cathepsin D expression. CSE exposure may also decrease hCG-β production as an endocrine marker, implying that cigarette smoke has adverse effects during pregnancy.

Computational insights into the molecular interactions of environmental xenoestrogens 4-tert-octylphenol, 4-nonylphenol, bisphenol A (BPA), and BPA metabolite, 4-methyl-2, 4-bis (4-hydroxyphenyl) pent-1-ene (MBP) with human sex hormone-binding globulin

Environmental contamination has been one of the major drawbacks of the industrial revolution. Several man-made chemicals are constantly released into the environment during the manufacturing process and by leaching from the industrial products. As a result, human and animal populations are exposed to these synthetic chemicals on a regular basis. Many of these chemicals have adverse effects on the physiological functions, particularly on the hormone systems in human and animals and are called endocrine disrupting chemicals (EDCs). Bisphenol A (BPA), 4-tert-octylphenol (OP), and 4-nonylphenol (NP) are three high volume production EDCs that are widely used for industrial purposes and are present ubiquitously in the environment. Bisphenol A is metabolized in the human body to a more potent compound (MBP: 4-Methyl-2, 4-bis (4-hydroxyphenyl) pent-1-ene). Epidemiological and experimental studies have shown the three EDCs to be associated with adverse effects on reproductive system in human and animals. Sex hormone-binding globulin (SHBG) is a circulatory protein that binds sex steroids and is a potential target for endocrine disruptors in the human body. The current study was done in order to understand the binding mechanism of OP, BPA, NP, and MBP with human SHBG using in silico approaches. All four compounds showed high binding affinity with SHBG, however, the binding affinity values were higher (more negative) for MBP and NP than for OP and BPA. The four ligands interacted with 19-23 residues of SHBG and a consistent overlapping of the interacting residues for the four ligands with the residues for the natural ligand, dihydrotestosterone (DHT; 82-91% commonality) was shown. The overlapping SHBG interacting residues among DHT and the four endocrine disruptors suggested that these compounds have potential for interference and disruption in the steroid binding function.