Assessment of an in vitro model of human cells to evaluate the toxic and irritating potential of chemical compounds

We attempted to induce differentation in unidifferentiated NCTC2544 human keratinocyte line, by exposure to ZnSO₄ and CaCl₂. Analysis of specific markers, transglutaminase I, involucrin and loricrin, show that basal NCTC2544 (BL) reached spinous- (SL) and granular-like (GL) phenotypes. BL-, SI- and GL- NCTC were exposed to SDS, as irritant stimulus and Neutral red uptake (NRU) and MTT cytoxicity tests evidenced a relatively higher toxicity in SL- and GL cells on lysosomes respect to mitochondria. ILIα cytokine was monitored as early inflammation marker. The complex of data provides evidence for the suitability of our in vitro model to the analysis of cytotoxic/biological effects of topically applied exogenous compounds.