thiophanate methyl effects on Danio rerio embyonic development: morphological and molecular alterations

INTRODUCTION: The Thyofanate Methyl is a pesticide and fungicide used in agriculture [1-2]. Our aim was therefore to assess the effects of toxicity and teratogenicity of acute doses of thiophanate methyl on embryonic development of Danio rerio[3]. METHODS: Embryos were exposed to different thyofanate metil concentrations, from 1µg/L to 10mg/L, for 144 hours at 28°C and were observed every 24 h for mortality and sublethal effects. The expression of MyoD, myogenin and myf5 genes was observed by in situ hybridization[4-5]. The 6 days larvae were labeled with anti-acetylated tubulin antibody, colored by diaminobenzidine (DAB) [6]. RESULTS and CONCLUSIONS: Survival and early development of the embryos were not obviously influenced by Thyofanate Methyl concentrations below 10mg/L, but at this concentration the embryos displayed alterations in neural development included weak tactile responses, loss of equilibrium and inability to swim. These treated embryos showed also: 1) an alteration of the spatial distribution of transcripts of MyoD and Myf-5 and myogenin signal was absent. 2) the localization of acetylated tubulin showed the breakage and the disorganization of the lateral line. Therefore, thiophanate-methyl at a concentration of 10 mg /L alters both skeletal muscle differentiaiton that the peripheral nervous system axogenesis. Our studies suggest that the negative effects of T.M. on vertebrate embryogenesis are substantial, therefore the T.M. is a possible contaminant of agriculture areas.