| Environmental endocrine disrupting chemicals (EDCs) may disturb the sex hormone level of organisms, thereby affected the sex determination and reproduction process of many teleost fish. It had been reported that many EDCs such as pesticides, synthesized chemicals and estrogen can cause estrogenic effects. Estrogenic chemicals like 4-NP, bisphenol A, 4-PP, EE2 can influence the expression level of many sex-determining-related genes. Monocrotophos (MCP) is one of organophosphorous pesticides with high water solubility, which had been proved can induce fish vitellogenin (VTG) production. However there was few reports of the effects of MCP on fish sex determination. In order to research the effects of MCP on fish sex determination, we chosed Zebrafish (Danio rerio) which was a alive model organism for EDCs filtration recommended by EPA as materials. Zebrafish was a perfect model organism for the research of fish sex determination. As Zebrafish developed to 10-12dph, a ovary-like gonad arised in all larvals; to 21-25dph, sex differentiation started, ovary-like gonad developed into ovary or testis; to 30dph, sex differentiation completed; to 42-49dph, special testis structure could be identified in the gonad; 90-120dph, Zebrafish becomed matures. Vasa gene and Cyp3c1 gene were important sex-determing related genes. Vasa gene was not only a special marker for Zebrafish Primordial Germ Cells (PGCs), but also a special marker for Human PGCs. Cyp3c1 gene was a new discovered sex-determing related gene in Zebrafish. Thereby, we chosed Zebrafish larvals at 0-21dph, 0-30dph and 0-42dph moment and 4-month male mature Zebrafish for experiments. Real-time Quantitative PCR technique was taken for examining the affects of 0.001, 0.01and 0.1mg/L MCP on Zebrafish Vasa gene and Cyp3c1 gene expression. The results showed that:(1) In the Zebrafish larval exposure experiments, the quantity of Vasa gene and Cyp3c1 gene expression at 21, 30 and 42dph were 0.0043±0.0034, 0.0126±0.0034, 0.0644±0.0171 and 0.0098±0.0041, 0.0231±0.0176, 0.1478±0.0443, showed that MCP gradually enhanced the Vasa gene and Cyp3c1 gene expression level during the sex differentiation process of Zebrafish.(2) 0.001, 0.01 and 0.1mg/L MCP were adopted for Zebrafish larval exposure experiment. It was found that 0.01 and 0.1mg/L MCP could enhance the Vasa gene expression level, the Vasa gene expression quantity of 0.01mg/L MCP group was obviously much higher than not only the control group but also the 0.001, 0.1mg/L and E2 group.(3) 0.001, 0.01 and 0.1mg/L MCP were adopted for Zebrafish larval exposure experiment. It was found that 0.01 and 0.1mg/L MCP could enhance the Cyp3c1 gene expression level at 21dph, it was also found that the Cyp3c1 gene expression quantity in the 0.01 and 0.1mg/L MCP group were similar to the E2 group. But there wasn't any obvious Cyp3c1 gene expression differentiation between the MCP exposure group and the control group at 30 and 42dph.(4) 0.001, 0.01 and 0.1mg/L MCP were adopted for mature Zebrafish exposure experiment. After 28d, it was found that the Vasa gene expression level was enhanced in all the 0.001, 0.01, 0.1mg/L MCP groups and E2 groups. The Vasa gene expression quantity was much more than 13 times of the E2 group. Above all, MCP could enhance the Vasa gene expression level in Zebrafish larvals at 21, 30 and 42dph. MCP could enhance the Cyp3c1 gene expression level in Zebrafish larvals at 21dph too. These results showed that MCP could affect the sex determination process of Zebrafish. The affects of MCP on Zebrafish Vasa gene and Cyp3c1 gene expression level in larvals was highly similar to E2. Considered that E2 was a putative environmental estrogen, which could cause estrogenic effects on fish, we conclude that the affects of MCP on Zebrafish Vasa gene and Cyp3c1 gene expression showed that MCP could affect the sex determination process of fish, and MCP had an estrogenic activity. During the mature male Zebrafish exposure experiment, the results that MCP enhanced the Vasa gene expression level in all 0.001, 0.01, 0.1mg/L MCP and E2 groups also proved our conclusion.
|
PDF Full Text Request