Developmental Toxicity Of Typical Heavy Metals And Flame Retardant Environmental Contaminants To Zebrafish Embryos

With the development of the economy,the production and use of chemicals in the worldwide are increasing rapidly.At the same time,a large number of chemicals inevitably enter the natural waters through various channels,which poses a potential threat to the health of humans and wildlife.Therefore,in this study,growth hormone/insulin-like growth factors(GH/IGFs)axis PCR array of zebrafish(Danio rerio)larvae was developed based on the quantification of mRNA expressions of 19 genes that were confirmed for risk assessment of environmental chemicals.The main results are as follows:1.In normal culture experiment,the 96 hpf is a relatively susceptible exposure window for larvae growth and development as the rate of body growth between 72 and 96 hpf was greater than that between 96 and 120 hpf.In addition,our results showed that mRNA expressions of the majority of genes along the GH/IGFs axis were extremely up-regulated in 96 hpf larvae compared with the 2 hpf larvae and the greater increased rates of mRNA expressions of some genes involved in GH/IGFs axis were observed at 96 hpf.According to the OECD standard method for acute toxicity test of zebrafish embryos,the 96 hpf could be selected as a sampling point when evaluating the effects of chemicals on body growth and gene transcription of GH/IGFs axis in zebrafish embryos/larvae.2.Zebrafish embryos were exposed to each of four concentrations of the six representative chemicals,bisphenol A(BPA),perfluorooctane sulfonates(PFOS),tris(1,3-dichloroisopropyl)phosphate(TDCIPP),cadmium chloride(CdCl2),mercury(II)chloride(HgCl2)and lead(II)acetate(PbAc)from 2 h post fertilization(hpf)to 96 hpf.Developmental endpoints and transcriptional profiles of the genes involved in GH/IGFs axis of zebrafish larvae were examined at 96 hpf.Body length of zebrfish larvae was found to be a more susceptible endpoint in zebrafish embryo toxicity test than other endpoints,including survival rate,hatching rate,malformation incidence and heart rate after exposure to each of those representative chemicals selected.Perturbation of mRNA expressions of GH/IGFs axis genes accompanied by decreased body length indicated that indicated that the growth inhibition observed might be attributed to the dysregulation of GH/IGFs axis.Therefore,these information obtained from GH/IGFs axis PCR array of zebrafish embryos/larvae might be used to predict the adverse effects of body length development via delineating chemical-induced modes of action and alterations in the expressions of GH/IGFs genes could be used for risk assessment of chemicals.