XXII Congresso Brasileiro de Toxicologia, Balneário Camboriú-SC, 25-28 Maio 2022.
Camila Martins. Kawakami, Gustavo Henrique da Silva, Kézia Moura, Ana Lúcia Tabarini Alves Pinheiro, Adriano da Silva Pinheiro, Samara Eberlin, Lorena Rigo Gaspar, Thais Fuzinaga, Eduardo Vicente, Gustavo Facchini.
The recent scenario of COVID-19 has resulted in an increase in hand cleansing products such as soaps, synthetic detergents, antiseptic handwashes and alcohol-based hand sanitizers. Consequently, it has been observed an emerging of several skin conditions including irritant contact (ICD) and allergic contact dermatitis (ACD) due to the excessive personal hygiene measures. These skin problems may result from a cascade of events which involve cell damage, inflammatory responses, cytokines release and activation of dendritic and T-cells; the latter being a key biological event underlying skin sensitization. Chlorhexidine is an effective antiseptic agent which is widely used in cosmetic, hospital products and medicines. Although clinical studies for chlorhexidine are common, the in vitro assessment and the molecular mechanisms involved in the irritant and allergic contact dermatitis are rarely reported. Evaluate the skin irritation and skin sensitization potential of a commercial formulation containing the antiseptic chlorhexidine (1%) by in vitro methods. The skin irritation potential was evaluated according to OECD TG 439 through the determination of cell viability in ex vivo human skin fragments using the vital dye MTT. Additionally, the inflammatory cytokine IL-1α was quantified. For skin sensitization assessment, the in chemico direct peptide reactive assay (DPRA) was performed following OECD TG 442C, which evaluates the cysteine- or lysine-containing peptide depletion using high-performance liquid chromatography (HPLC). The skin sensitization was also evaluated using the human cell line activation test (h-CLAT, OECD TG 442E), which quantifies changes of cell surface marker expression (CD86 and CD54) on a human monocytic leukemia cell line (THP-1 cells), using flow cytometry. The results of skin irritation (OECD TG 439) demonstrated that the positive control LSS (5%) was considered irritant since it reduced more than 50% in cell viability when compared to non-treated control. On the other hand, the product containing chlorhexidine (1%) was classified as non-irritant, since they presented cell viability of approximately 73.55%. In addition, treatment with the product assessed did not promote a significant increase in the inflammatory cytokine IL1-α release when compared to baseline control. The in chemico DPRA assay demonstrated that, as expected, the positive control dinitrochlorobenzene (DNCB) presented positive prediction for skin sensitization. The ingredient and the product assessed also presented positive prediction for skin sensitization (low reactivity) according to OECD TG 442C. Finally, the results from h-CLAT assay showed that the positive control DNCB presented relative fluorescence intensities (RFI) ³ 150 for CD86 and ³ 200 for CD54, which classifies this substance as sensitizing, according to OECD TG 442E. Moreover, the product containing chlorhexidine (1%) also presented sensitizing potential since RFI for CD86 were above the acceptable value for non-sensitizing substances (on going experiment). The results showed that the product containing chlorhexidine (1%) did not present potential for skin irritation. In addition, it demonstrated positive prediction for skin sensitization potential, for both in chemico DPRA and in vitro h-CLAT assays. Further studies should be conducted with this hand hygiene products category to better understand the molecular mechanisms involved in the irritant and allergic contact dermatitis.
