Effects of 2,4‐dichlorophenol on the expression of vitellogenin and estrogen receptor genes and physiology impairments in Chinese rare minnow (Gobiocypris rarus)

Abstract

2,4-Dichlorophenol (2,4-DCP) is known as a toxicant, but unknown as an environmental endocrine disruptor. In the present work, Chinese rare minnow (Gobiocypris rarus) was exposed to 0.03, 0.3, and 3 mg/L 2,4-DCP for 3 d and 0.1, 0.3, and 1 mg/L 2,4-DCP for 21 d, respectively. Endpoints including somatic index, vitellogenin (VTG) mRNA and protein level, estrogen receptor (ER) mRNA and histopathology were measured. In the 3-d exposure experiment, the effect concentrations were 0.3 mg/L and above, and in 21-d exposure, the effect concentrations were 0.1 mg/L and above. When exposed to the effect concentrations, GSI was significantly reduced for both male and female, ER mRNA was upregulated in male and downregulated in female. There were no significant variations of VTG mRNA in both male and female in 3-d exposure and in male in 21-d exposure. However, VTG mRNA in female in 21-d exposure was upregulated, corresponding to an increase of VTG protein in serum. Histopathological observation showed that ovaries were degenerated in the effect concentrations, where follicular atresias were more frequently observed. Because the sex hormones related genes and toxicological endpoints were affected in the dose-dependent manner, the results suggest that 2,4-DCP could be a potential endocrine disruptor and might cause adverse effects in female sex organs through interruption of ER-mediated processes.

2, 4-Dichloro-6-nitrophenol, a photonitration product of 2, 4-dichlorophenol, caused anti-androgenic potency in Chinese rare minnows (Gobiocypris rarus)

“…Nevertheless, cellular vacuolization, hepatocyte hypertrophy and nuclear pyknosis were observed in the liver of the rare minnows, which confirmed the hepatotoxicity induced by DCNP. Similar types of histological damage have been observed in fish exposed to several substituted phenols such as nonylphenol, nitrophenol and DCP (Lam et al, 2013;Zhang et al, 2008). Additionally, DCNP has been shown to induce oocyte and testis degeneration in this study.…”

“…In this study, the plasma VTG level increased in male fish after DCNP exposure, which confirmed that DCNP was acting as a xenoestrogen. It has been reported that substituted phenols such as 2.4-DCP induce the synthesis of VTG in many fish species (Zhang et al, 2008). However, a slight decrease in female fish at a concentration of 200 mg/L occurred in this study, suggesting weak estrogenic activity of DCNP in female fish.…”

“…Moreover, Nishihara have reported that substituted phenols (e.g., BPA, 3,4-dichlorophenol, and pentachlorophenol) were potential agonists to the rat ER (Nishihara et al, 2000), but their anti-androgenic activity was measured using a recombinant yeast assay (Li et al, 2010). In addition, in vivo studies have indicated that substituted phenols can alter the expression of the steroid receptors associated with changes in the metabolism of xenobiotics and steroid hormones (Zhang et al, 2008). Therefore, potent estrogenic effects of substituted phenols (e.g., Nonylphenol and Tribromophenol) have been found in vitro (Bonefeld-Jorgensen et al, 2007) and in vivo (Deng et al, 2010;Duffy et al, 2014).…”

Current exposure of 200 pregnant Danish women to phthalates, parabens and phenols

“…Triclosan (TCS), benzophenone-3 (BP-3) (a u.v.-filter) and several other phenols also appear to have endocrine-disrupting activity with adverse effects on, e.g. thyroid and reproductive function (Zhang et al 2008, Li et al 2010, Rodriguez & Sanchez 2010, Jung et al 2012, Krause et al 2012, Henry & Fair 2013.…”

Pentachlorophenol affected both reproductive and interrenal systems: In silico and in vivo evidence

“…Rare minnow (Gobiocypris rarus), which is mainly distributed in upstream of the Yangtze River, has been selected as an appropriate native species for risk assessment by Chinese government due to its small size, ease of culture and sensitivity to chemical exposure (Zha et al, 2007(Zha et al, , 2008Zhang et al, 2008b). In vivo models for evaluating the disruptions on HPG/I axis was developed using Chinese rare minnow, and have been validated useful for studying endocrinedisrupting effects and the underlying molecular mechanisms (Zhang et al, 2008a;Yang et al, 2010Yang et al, , 2011.…”