Silva, Michelle S.; Facchini, Gustavo; Silva, Gustavo H.; Picon, Francini C.; Pinheiro, Ana L. T. A.; Pinheiro, Adriano S.; Eberlin, Samara.
Cell cultures are essential tools for the development of alternative methods to the use of animals to evaluate the safety of products intended for human use. Many toxic xenobiotics to the respiratory tract not only cause cell death, but also induce pro-inflammatory responses that may potentiate airway injury. Thus, to assess the inhalation toxicity of a product, it is important to have an integrated view of its role in inflammation and apoptosis using a test system that mimics respiratory tract conditions. To develop an experimental model in air-liquid lung cell interface culture to evaluate the inhalation toxicity potential of the volatile components from the hair straightening procedure. Pulmonary fibroblasts cultured in air-liquid interface were exposed in controlled atmosphere during the application of hair straighteners and formaldehyde (15%) in hair tresses. After the procedure the cells were maintained in an incubator for further cellular viability evaluation (MTT) and the mediators Caspase 3/7 and SERCA2. The results showed that the exposure of the cultures to the treatment with straightening promoted cell death - activation of Caspase 3/7 (21.17%, P<0.05) and MTT (11.44%, P<0.01) and reduction of SERCA2 (20.95%, P<0.01) after 1 hour of incubation, but after 24 hours these values were reestablished. On the other hand, the exposure of cell cultures to 15% formalin vapor significantly and irreversibly increased the cell death and inflammatory response, when compared to the baseline group. We observe a decrease of the viability in 74.11% and 76.82% (P<0.001) by MTT technique, an increase of 3.14 and 4.18-fold in Caspase 3/7 activation, and a reduction of SERCA2 in 20.95% and 18.20% (P<0.01), after 1 and 24 hours, respectively. The experimental methodology presented shows an important advance in the evaluation of cosmetic toxicology in the sense of developing tools that allow us to reduce, replace and/or refine the use of experimental animals. In addition, unlike the inhalation toxicity models in animals where the parameter observed is death alone, the air-liquid interface model proposed in the present study allows a broad view of the effect of the hair straightening on the respiratory tract considering even impacts of the inflammatory response.