Histological alternation and vitellogenin induction in adult rare minnow (Gobiocypris rarus) after exposure to ethynylestradiol and nonylphenol

Abstract

Adult rare minnow (Gobiocypris rarus) were exposed to 0, 1, 5, and 25 ng/l (nominal concentrations) of 17a-ethynylestradiol (EE 2 ) and 3, 10, and 30 lg/l (nominal concentrations) of 4-nonylphenol (NP) under flow-through conditions for a period of 28 d. Low mortality was observed at 5 and 25 ng/l EE 2 and the growth of fish reduced significantly at 25 ng/l EE 2 compared to controls. However, the gonadosomatic indices (GSI) of male fish were significantly higher in 1 ng/l EE 2 treatments and in 10 and 30 lg/l NP treatments (p < 0.05). Renal somatic indices (RSI) of male fish in EE 2 treatments were significantly higher than those in controls (p < 0.05). In contrast, significantly decreased GSI and RSI of female fish could only be observed in 5 and 25 ng/l EE 2 treatments (p < 0.05). Hepatosomatic indices (HSI) of male fish were significantly higher in 25 ng/l EE 2 treatments. However, significantly increased of HSI of female fish could only be observed in 1 ng/l EE 2 treatments. Plasma vitellogenin (VTG) induction could be observed in males after exposed to different concentrations of EE 2 and NP, and plasma VTG concentrations in females exposed to 5 and 25 ng/l EE 2 were also significantly higher than in controls (p < 0.05). At level higher than 5 ng/l EE 2 or 30 lg/l NP, hepatic tissue and renal tissue impairment of males could be observed. The pathological male liver was associated with a hypertrophy of hepatocytes and damages to cellar structure and accumulated eosinophilic material. Renal tissue showed different pathological effects which was reflected by accumulated eosinophilic material, hemorrhages within the kidney tubules and hypertrophy of the tubular epithelia. Also at these levels of exposure, feminization of male fish could be noticed and parts of males manifested the testis-ova phenomenon. Ovaries of female rare minnow in 25 ng/l EE 2 treatment group were degenerated. Therefore when exposed to EE 2 and NP even at environmental observed concentrations, adverse effects could occur in the reproductive system of adult fishes. The observed hepatic tissue and renal tissue impairment should be due to the induction and accumulation of VTG in organs, especially in males.

Transcriptional expression analysis of ABC efflux transporters and xenobiotic-metabolizing enzymes in the Chinese rare minnow

“…The brood stock of rare minnow was raised in a flow through system with dechlorinated tap water (pH: 7.2-7.6; hardness: 44-61 mg CaCO 3 l −1 ; and temperature: 25 ± 1 • C) with a photo period of 16:8 h (light:dark) and has been used for testing chemicals in our laboratory for more than 10 years (Zha et al, 2007;Li et al, 2009). The fish were fed on commercial food pellet (Trea, Germany) at a rate of 0.1% body weight per day and newly hatched brine shrimp (Artemia nauplii) two times daily.…”

“…After 12 days exposure, the body lengths and body weights of the rare minnows were measured. Then the fish were sacrificed, the tissues in each group were fixed in Bouin's solution for histopathological examination, the detailed protocol of histopathology was according to previous description of our laboratory (Zha et al, 2007;Li et al, 2009), and tissues from the rest of rare minnow were flash-frozen in liquid nitrogen, and stored at −80 • C.…”

“…The rare minnow is distributed mostly in the upstream region of the Yangtze River and in the Sichuan Province of China. It is considered to be an appropriate species for the assessment of chemical toxicity due to its small size, ease of culture, short life cycle and prolific egg production with high fertilization and hatching rates (Zha et al, 2007;Li et al, 2009).…”

Combined effects of estrogenic chemicals with the same mode of action using an estrogen receptor binding bioassay

“…after the long-term exposure to environmental observed concentrations (ng/L) aggravate these worries (Hotchkiss et al, 2008;Vandenberg et al, 2012;Zha et al, 2007). Particularly, steroid estrogens (both natural and synthetic) and phenolic xenoestrogens receive more attention because of their non-ignorable estrogenicities and widespread applications (Peng et al, 2006).…”

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.…”