RESUMO
There is evidence that cylindrospermopsin (CYN) exerts reproductive toxicity in mice. However, little information is available concerning the toxicity of CYN in nonmammalian vertebrates. Here, we investigated the direct action of CYN on female reproduction by studying germinal vesicle breakdown, transcript abundance, caspase-3 activity, and testosterone production using cultured follicle-enclosed zebrafish oocytes as a model system. Treatment of follicles with 1,000 µg/L CYN significantly increased GVBD, Caspase-3 activity, and hCG-induced testosterone secretion. Exposure to CYN also reduced the abundance of 3ßhsd as well as hCG-induced fshr and era transcripts and increased cyp19a1 mRNA levels. In summary, this study provides a framework for a better understanding of the adverse action of CYN on female reproduction in zebrafish and other vertebrate species. The findings are also relevant to developing valid biomarkers for CYN by measuring zebrafish oocyte maturation and gene expression.