Enantioselective induction of estrogen-responsive gene expression by permethrin enantiomers in embryo-larval zebrafish
Introduction
Over the past decades, increasing concern has arisen regarding environmental compounds with the capacity to alter normal endocrine function of wildlife and human (McKinlay et al., 2008). Such compounds are known as endocrine-disrupting chemicals (EDCs), and it has become evident that many currently used chemicals, including insecticides, have such hormonal activity. These compounds may interfere with developmental and reproductive functions in aquatic species, including altering sex ratios, delaying sexual differentiation, damaging gonad development, and changing plasma steroid levels. Furthermore, evidence is now emerging that EDCs may influence reproductive and neuroendocrine systems, senescence, and even carcinogenesis in humans and wildlife (Rhind, 2005, Patisaul et al., 2006).
Manmade pesticides are among the most common sources of EDCs worldwide. Approximately 25% of currently used pesticides are chiral, and this ratio is still increasing (Liu et al., 2005a). In most cases, enantiomers are known to interact selectively with biological systems, and may behave as totally different compounds (Müller and Kohler, 2004). Recent studies have shown that enantiomers of chiral pesticides behave enantioselectively in their effects on aquatic toxicity and environmental fate (Lewis et al., 1999, Liu et al., 2005b, Liu et al., 2005c).
Permethrin (PM), one of the most common synthetic pyrethroids, is widely used for the control of agricultural and indoor pests. PM has two asymmetric positions and contains two pairs, including four ((+)-cis, (−)-cis, (+)-trans, and (−)-trans)) enantiomers. It is valuable to point out that the use of pyrethroids is expected to increase further because of restrictions on the use of organophosphorus pesticides (Qin and Gan, 2006). In fact, the Chinese government gave SPs the first priority to be used for preventing the occurrence of infectious disease after the great 2008 Wenchuan earthquake. Although PM is highly hydrophobic and immobile in soil, it is easily transported offsite into aquatic systems via runoff or soil erosion. As a result, its use will influence aquatic biological systems, even in very low concentrations. In fact, a previous study reported PM concentrations was around 1–5.5 ng g−1 in dry weight basis collected at the lower Missouri River of USA (Echols et al., 2008). The endocrine-disrupting activity of PM has been suggested in some in vitro and in vivo experimental systems (Go et al., 1999, Perry et al., 2007). Moreover, our recent study strongly suggested the occurrence of significant enantioselectivity in estrogenic activity of PM enantiomers in adult male zebrafish (Danio rerio) (Jin et al., 2008a). However, whether or how PM executes its potential hormonal activity in other life stages still remain unknown.
Zebrafish have been used as a predominant test model for hormonal activity assessment of EDCs. Toxicity investigations have been applied to different developmental stages in zebrafish-embryo, larvae, juvenile and adult (Brion et al., 2004). The use of fish in their early development stages in exposure tests has proven to be a convenient and effective approach to examining aquatic toxicity (Kishida et al., 2001, Andersen et al., 2003). Thus, embryo-larval zebrafish are an ideal model to analyze estrogenic activity in aquatic environment.
The aim of this study was to evaluate enantioselectivity in the endocrine-disrupting potential of PM, using embryo-larval zebrafish as the standard laboratory model. In this study, we adopted a real-time polymerase chain reaction (PCR) to determine the estrogenic effects of PM enantiomers by detecting the expression levels of estrogen-responsive genes in embryo-larval zebrafish exposed to PM enantiomer solutions for a period of 7 d immediately post-fertilization.
Section snippets
PM enantiomer separation and quantitative analysis
Analytical standard of racemic PM [99.2%, (3-phenoxyphenyl) methyl (1RS)-cis–trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate; cis/trans = 1:3] was purchased from Sigma (St. Louis, MO, USA). The method of separation of PM was performed with an established method described as Jin et al. (2008a). Briefly, separation of individual PM enantiomers was performed on a Jasco LC-2000 series HPLC system (Jasco, Tokyo, Japan). The column was a CHIRALCEL OJ-H column (4.6 mm ID × 250 mm) using
Induction of embryo-larval estrogenic-responsive gene expression as biomarkers
Fig. 1 showed that the expression levels of vtg1, vtg2, esrα, cyp19a and cyp19b mRNA in the zebrafish larvae were induced effectively when exposed to E2 for 7 d. The lowest concentration of E2 to significantly induce transcripts of these selected estrogenic-responsive genes were 50 ng L−1, and the induction in mRNA levels of vtg1, esrα, cyp19a and cyp19b were 5.0-, 2.6-, 2.3- and 5.4-fold at this concentration compared with those in the control treatment, while vtg2 was significant induced at 25 ng L
Discussion
Vtgs and esr have been widely used as biomarkers for detecting estrogenic EDCs in the aquatic environment, while real-time RT-PCR is one of the most sensitive in vitro and in vivo assay techniques (Yamaguchi et al., 2005, Jin et al., 2008b). Our results confirmed that the expression of vtg1, vtg2 and esr genes in newly hatched larval zebrafish could be induced rapidly and efficiently by exposing them to E2 for 7 d after fertilization, even at the very low concentration of 50 ng L−1 (Fig. 1). Some
Acknowledgments
This work was supported by a grant from the National Natural Science Foundation of China (No. 20577045), the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT 0653), the Natural Science Foundation of Zhejiang Province, China (No. Z506070).
References (31)
- et al.
Effects of exposure to 17α-ethinylestradiol during early development on sexual differentiation and induction of vitellogenin in zebrafish (Danio rerio)
Comp. Biochem. Physiol. C
(2003) - et al.
Impacts of 17-estradiol, including environmentally relevant concentrations, on reproduction after exposure during embryo-larval-, juvenile- and adult-life stages in zebrafish
Aquat. Toxicol.
(2004) - et al.
Molecular cloning and function analysis of high-density lipoprotein-binding protein
Comp. Biochem. Physiol. B
(2003) - et al.
Estrogenic and antiprogestagenic activities of pyrethroid insecticides
Biochem. Biophys. Res. Commun.
(1998) - et al.
Enantiomer-specific activity of o,p′-DDT with the human estrogen receptor
Toxicol. Lett.
(2001) - et al.
Induction of hepatic estrogen-responsive gene expression by permethrin enantiomers in male adult zebrafish
Aquat. Toxicol.
(2008) - et al.
Effects of endocrine disrupting chemicals on the expression of CYP19 genes in zebrafish (Danio rerio) juveniles
Aquat. Toxicol.
(2004) - et al.
Estrogen and xenoestrogens upregulate the brain aromatase isoform (P450aromB) and perturb markers of early development in zebrafish (Danio rerio)
Comp. Biochem. Physiol. B
(2001) - et al.
Analysis of relative gene expression data using real-time quantitative PCR and the 2−ΔΔCt method
Methods
(2001) The levo enantiomer of o,p′-DDT inhibits the biding of 17β-estradiol to the estrogen receptor
Life Sci.
(1987)
Endocrine disrupting pesticides: implications for risk assessment
Environ. Int.
Neonatal genistein or bisphenol-A exposure alters sexual differential of the AVPV
Neurotoxicol. Teratol.
Environmental pyrethroid and organophosphorus insecticide exposures and sperm concentration
Reprod. Toxicol.
Short-term effects of endocrine-disrupting chemicals on the expression of estrogen-responsive genes in males Medaka (Oryzias latipes)
Aquat. Toxicol.
Activation of pS2 gene transcription is a primary response to estrogen in the human breast cancer cell line MCF-7
Proc. Natl. Acad. Sci. USA
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