EFFECTS OF CADMIUM AND ALUMINIUM ON GROWTH AND MOTILITY IN Danio rerio EMBRYOS

Cadmium (Cd) is known as a potent toxic metal also at low concentrations. It is biologically non-essential and subject to the bioaccumulation phenomenon. Aluminium (Al) is the third most abundant element of the earth. Some investigations on environmental toxicology revealed that high concentrations of Al may present a major threat for humans, animals and plants causing many diseases1. Our previous studies showed that both Cd and Al affect development of Danio rerio (zebrafish) and damage the nervous system although at significantly higher concentrations for Al2,3. D. rerio is becoming a focus of neurobehavioral studies4. In the present study we have analysed the effects of Cd and Al at sublethal concentrations on the development of D. rerio by the observation of embryos dechorionation and motility at 78 hpf (hours post fertilization). The treatments were performed on embryos at 6 hpf for 72 hours. Four groups of embryos were exposed to Cd at the concentrations of 9, 18, 36 and 72 μM. Other three groups were instead exposed to Al at concentrations of 50, 100 and 200 μM. Another group of embryos was kept as control. Cadmium harmed the embryos at early stages of development by a delay of the exit from the chorion and this effect increased significantly at higher concentrations. Also Al caused a similar delay but this inhibition appeared particularly evident at lower concentrations. Moreover we tested different parameters for the study of embryos motility at 78 hpf using the DanioVision. Both metals, albeit in different way, affected significantly the behavioral parameters such as Distance moved, Velocity mean, Cumulative movement, Meander and Heading. These results are indicative of the toxic effect of Cd and Al at sublethal concentrations on embryos development of D. rerio suggesting the need for further experiments to elucidate the different mechanisms underlying such alterations. 1. Barabasz W et al. Pol J Environ Stud 2002, 11:199-203. 2. Monaco A et al. J Appl Toxicol 2016, 36:1629-38. 3. Monaco A et al. Eur J Histochem 2017, 61:28-33. 4. Senger MB et al. Cell Biol Toxicol 2011, 27:199-205.