Environmental Science: Nano 2018-04-11

Adverse reproductive performance in zebrafish with increased bioconcentration of microcystin-LR in the presence of titanium dioxide nanoparticles

Houcheng Cheng, Wei Yan, Qin Wu, Juanli Lu, Chunsheng Liu, Tien-Chieh Hung, Guangyu Li

Index: 10.1039/C8EN00174J

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Abstract

Abstract The aim of the present study was to investigate the reproductive effects of microcystin-LR (MCLR) in the presence of titanium dioxide nanoparticles (n-TiO2). Five-month-old zebrafish were exposed to MCLR (0, 0.5, 4 and 32 μg/L) alone or combined with n-TiO2 (100 μg/L) for 21 days. The accumulation of both n-TiO2 and MCLR was observed in the fish liver, brain and gonad. Enhanced bioconcentration of MCLR was measured in coexposure groups. Joint exposure to both n-TiO2 and MCLR significantly reduced the fecundity of adult fish compared to only MCLR treatment. Histopathological examination revealed no obvious change in the morphology of ovary and testis, while a significant decline of estradiol (E2) and testosterone (T) levels as well as disordered transcription patterns of genes along the hypothalamus-pituitary-gonadal (HPG) axis was observed. N-TiO2 may act as a carrier of MCLR and increase its concentration when contacted with zebrafish, which exacerbated reproductive endocrine dysfunction as a consequence.