Amitraz mechanisms of cytotoxicity in a characterized SH-SY5Y cells spheroid model

In recent years, spheroids (tridimensional cell cultures) have emerged as a more physiologically relevant replacement for monolayer models. Their distinctive advantage is the formation of an extracellular matrix that facilitates enhanced cellular interaction and communication, approximating the conditions observed in vivo. Therefore, the potential for conducting intricate cellular and molecular techniques in these models could offer a more precise assessment of pivotal proteins within various cellular pathways of interest. Amitraz (AMZ), an acaricide classified as a formamidine chemical, has been detected in honey at concentrations exceeding legal limits. The objective of this study was to characterize a spheroid model of SH-SY5Y cells and determine the cytotoxic effect of AMZ and its mechanisms of action on this spheroid. The formation of mature spheroids was observed on the seventh day following seeding. The results obtained with SH-SY5Y spheroids were an IC₅₀ of 238.8 ± 17 µM and 224.3 ± 19 µM, respectively, after 24 and 48 h of exposure by the MTT assay. The findings revealed that AMZ did not exhibit any indications of inflammatory over-expression markers in the spheroids. Nevertheless, at 238.8 µM of AMZ, an increase incidence of late apoptosis within spheroid cells and Bcl-2 protein expression in peripheral spheroid cells were observed through annexin V and propidium iodide probe and immunofluorescence analysis. In conclusion, the results demonstrated that spheroids could be useful for an accurate assessment of toxicity, representing a viable alternative method for determining the mechanisms of action of AMZ and related compounds.