Lipid assessment of Rhinella arenarum larvae exposed to copper oxide nanoparticles and CuCl2·2H20 salt.

GABRIELA SVARTZ; ACQUARONI, MERCEDES; TERESA FONOVICH

Montevideo

Congreso; SETAC Latin America 15th Biennial Meeting.; 2023

SETAC LA

Copper oxide nanoparticles (CuO-NPs) are increasingly used in various industry sectors for their unique properties, which make these materials very promising and efficient, but are also responsible for their higher reactivity towards other molecules. These reasons make it necessary to know its possible toxic effects. Aquatic environments are the main final disposal of these NPs that can reach them during their life cycle (production, use and disposal) and they have generated concerns related to the conservation of more vulnerable groups, such as amphibians. The aim of this work was to evaluate the toxicity of the CuO-NPs and its respective salt (CuCl2·H20) in the lipid content (neutral lipids, fatty acids and phospholipids) of larvae of the common South American toad, Rhinella arenarum. In this sense, standardized bioassays were performed up to 21 days of exposure to different sublethal concentrations: 5 and 10 mg/L CuO-NPs; 0.1 and 0.5 mg/L CUCl2·2H20. The bioassays were semi-static with replacement of the solutions every 48 h, treatments were done by triplicate, and a control group without exposure was simultaneously maintained. After exposure, the pool of individuals of each treatment was weighted, then they were homogenized and the lipids were extracted by a mixture of solvents (chloroform:methanol 2:1). The phospholipids quantification was performed by Rousser et al. (1970) method, neutral lipids and free fatty acids were separated by thin layer chromatography (TLC) on silica gel plates and detected with iodine vapors and sulphuric acid treatment, and triglyceride levels were preliminary determined by an enzymatic reactions kit (TG color GPO/PAP AA, Wiener lab, Argentina). The results show that the weight of individuals exposed to 0.5 mg/L salt was significantly lower than 0.1 mg/L salt. Although there were no significant differences in the amount of phospholipids between the control and the exposed treatments, a decreased tendency was observed at highest concentration of salt (0.5 mg/L). As phospholipids are the major lipids in biological membranes, this decrease may be due to delayed development in these exposed individuals, which is also related to the lower weight observed. The TLC separation of lipids shows no significant differences depending on the concentration of salt or nanomaterials, in the different bands of all acylglycerols and free fatty acids, between the treatments and the control.