Evaluation of Potential Risks to Human Health and Ecosystems During Exposure to Discarded Laboratory Chemical Mixtures by In Vitro Multimodel Approach

The toxicity of inorganic and organic mixtures (CER 16 05 06*), which derive from analytical laboratory waste, being often unstable, represents a relevant issue for their toxicological interactions. In compliance with the 3Rs policy adopted by the European Commission, a multimodel in vitro approach was set up. Toxicity and the proinflammatory potential of such mixtures were evaluated on human endothelial, epithelial cell lines (human endothelial cells from umbilical cord [HECV] and cervical cancer cells derived from Henrietta Lacks [HeLa]) and 3D-human-epidermis reconstructed model. Moreover, the effects of inorganic and organic mixtures on cellular bioenergetics and neuronal network were evaluated in terms of adenosine triphosphate (ATP) synthetic ability by rod outer segment (OS) disk and spontaneous electrical activity of rat cortical networks. Inorganic mixture resulted more effective than the organic one in reducing viability indexes of both human cell lines. In HeLa, expression of tumor necrosis factor-alpha gene was positively modulated by both mixtures, while the inorganic mixture reduced interleukin-18 gene levels and organic one lowered Hsp70 stress response gene. Dermal corrosion and irritation testing on a commercial 3D-human-epidermis reconstructed model showed a corrosive and irritant potential of inorganic mixture only. In addition, this latter impaired cellular bioenergy, in terms of ATP synthesis by purified rod OSs. Moreover, both mixtures exerted harmful effects on the spontaneous electrophysiology activity of rat neuronal networks, by means of microelectrode array-based platforms. Obtained data evidenced that both mixtures can be potentially harmful to workers and this in vitro multimodel approach could be a useful starting tool for the prediction of the potential risk to humans and ecosystems.