The use of gene expression as early biomarkers in larvae of Cichlasoma dimerus (Teleostei, Perciformes) exposed to the pesticide endosulfan.

PIAZZA, Y.; AMBERG, J.; GENOVESE, G.; LO NOSTRO, F.; SEPULVEDA, M.

Lima, Peru

Congreso; IX Congreso SETAC Latin America - II Congreso SETAC Perú.; 2009

SETAC Latin America

Endocrine disrupting chemicals can affect reproduction in vertebrates by altering the hypothalamus-pituitary-gonad axis function. The organochlorine insecticide endosulfan (ES) is currently banned in several countries due to its high toxicity to non-target animals. However it is still widely used in Argentina for the control of insects in crops of high commercial value. Exposure of fish to this pesticide can cause alterations on growth, development, and reproduction. The objective of our study was to analyze the expression of some genes related to reproduction in a freshwater cichlid fish (Cichlasoma dimerus) after exposure to environmentally relevant concentrations of endosulfan (0.03 and 0.1 μg/l). Fish were exposed to endosulfan throughout the period of sex differentiation. At 30 and 90 days post fertilization (dpf), a representative number of fish were collected and whole bodies (without head and tail) were preserved in RNAlater. Following the extraction of total RNA and synthesis of cDNA from individual bodies, the expressions of genes-of-interest were assessed using quantitative polymerase chain reaction. Genes-of interest included: fsh, lh, vasa, dmrt1, fox12, vtg, cyp19, and vp. Males exposed to the highest concentration of ES showed an up-regulation of fox12 at 90 dpf; an up-regulation of vtg expression at 30 dpf; and a down-regulation of vasa at 90 dpf. These results suggest that endosulfan might interfere with normal sex differentiation and development. Key words: fish larvae, gene expression, endocrine disruption, organochlorine pesticide, endosulfan.