Oxidative Stress and DNA Damage in Keratinocytes Treated with Bussulphan Veiculated in Artificial Saliva

• Published in: Biology of blood and marrow transplantation Vol. 25; no. 3; pp. S305 - S306
• Main Authors: de Carvalho, Danielle Lima Correa, Ferreira, Mariana Henriques, de Paula Eduardo, Fernanda, Bezinelli, Leticia Mello, Rosin, Flávia Cristina Perillo, Waisbeck, Tania Michele, Voguel, Cristina, Hamerschlak, Nelson, Corrêa, Luciana
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-03-2019
• ISSN: 1083-8791; 1523-6536
• DOI: 10.1016/j.bbmt.2018.12.659

During conditioning of hematopoietic stem cell transplantation, numerous chemotherapeutics are used, among them, busulfan (BU). This is an alkylating agent that generates intense toxicity induced by oxidative stress, which can lead to DNA damage and cause oral mucositis (MO). BU is found at salivary levels close to plasma levels, but it is not known whether salivary concentrations are toxic as much as plasma to the oral cavity. This work aimed to analyze oxidative stress and possible DNA damage in keratinocytes exposed to BU found in salivary doses. Human keratinocytes were cultured and the following groups were established: Control (no treatment), Control Saliva (exposure to artificial saliva) and BU (exposure to BU carried in saliva at 4.0, 4.5, 5.0 and 5.5 μg / mL). The cell viability and the number of cells with DNA fragmentation were evaluated by TUNEL assay, as well as the level of oxidative stress by quantification of sequestration of the radical DPPH, superoxide dismutase (SOD), catalase (CAT) and level of lipid peroxidation (PL). Through the comet assay, the percentage of fragmented DNA was evaluated. The effect of BU on keratinocytes was dose-dependent; the dose of 5.5 μg / mL without vehicle with saliva generated 76% cellular viability, differing from the Control group (p < 0.05); when the BU was delivered in saliva, all doses generated less viability than the BU without saliva (p < 0.001). In the TUNEL analysis, salivary BU treatment caused a higher frequency of cells with DNA fragmentation (p < 0.05 compared to controls), as well as lower sequestration potential of the DPPH radical (p < 0.05 compared to the controls). Catalase activity was higher in the BU group (p < 0.01 compared to the controls). Exposure to BU also generated a higher percentage of fragmented DNA (p < 0.05 compared to Control). It was concluded that the salivary concentration of BU is toxic to keratinocytes, inducing oxidative stress and increased DNA damage.