Evaluation of xenoestrogenic potential of propylparaben in zebrafish (Danio rerio)

OBJECTIVES: Xenoestrogenic potential of propylparaben (PP), one of the most commonly used preservatives in drugs, cosmetics and food, was investigated in vivo using zebrafish (Danio rerio). METHODS: Juvenile zebrafish (20 days post hatching) were exposed to three different concentrations of propylparaben (PP) dissolved in ethanol and added into the water. After 20 days of exposure the fish were euthanized and vitellogenin concentrations in their whole body homogenates were measured by the method of direct sandwich ELISA. Simultaneously, vitellogenin concentrations in either fish from the control group (exposed to solvent without the substance tested) and in fish from the positive control group (exposed to natural estrogen 17 beta-estradiol) were measured. RESULTS: Vitellogenin concentration in whole body homogenates of control fish was 400 (396-540) ng.ml(-1) (geometric mean (95% CI)). Zebrafish exposure to propylparaben at the concentrations of 0.1; 0.4 and 0.9 mg.l(-1) elicited statistically significant decline (P < 0.001) of vitellogenin production, i.e. geometric means of vitellogenin concentrations in whole body homogenates were 240 (186-311); 218 (175-270) and 270 (234-311) ng.ml(-1), respectively. Conversely, the geometric mean of vitellogenin concentration in whole body homogenates of zebrafish exposed to 100 ng.l(-1) of 17 beta-estradiol (positive control) was significantly higher (P < 0.001) than values in all other groups, i.e. 35 553 (16 860-74 968) ng.ml(-1). CONCLUSIONS: Our results suggest an antiestrogenic potential of propylparaben tested in vivo in juvenile zebrafish (Danio rerio). The estrogenic effect of 17 beta-estradiol was confirmed.