Dalberto Daiana, Nicolau Caroline Cardoso, Garcia Ana Leticia Hilario, Nordin Adriane Perachi, Grivicich Ivana, Silva Juliana da
Universidade Luterana do Brasil (ULBRA), Programa de Pós-Graduação em Biologia Celular e Molecular Aplicada à Saúde - PPGBioSaúde, Laboratório de Toxicologia Genética, Canoas, RS, Brazil.
Universidade Feevale, Programa de Pós-Graduação em Qualidade Ambiental, Laboratório de Ecotoxicologia, Novo Hamburgo, RS, Brazil.
Genet Mol Biol. 2020 May 29;43(2):e20190123. doi: 10.1590/1678-4685-GMB-2019-0123. eCollection 2020.
Cotinine is the main metabolite of nicotine, which is metabolized in the liver through a cytochrome P450 enzyme. Different studies point to genetic instability caused by nicotine, such as single and double DNA strand breaks and micronuclei formation, but little is known about the effect of cotinine. Therefore, the present in vitro study assessed the effects of cotinine on cell viability and DNA damage in SH-SY5Y neuroblastoma cells, as well as genotoxicity related to oxidative stress mechanisms. Comparisons with nicotine were also performed. An alkaline comet assay modified by repair endonucleases (FPG, OGG1, and Endo III) was used to detect oxidized nucleobases. SH-SY5Y neuronal cells were cultured under standard conditions and exposed for 3 h to different concentrations of cotinine and nicotine. Cytotoxicity was observed at higher doses of cotinine and nicotine in the MTT assay. In the trypan blue assay, cells showed viability above 80% for both compounds. Alkaline comet assay results demonstrated a significant increase in damage index and frequency for cells treated with cotinine and nicotine, presenting genotoxicity. The results of the enzyme-modified comet assay suggest a DNA oxidative damage induced by nicotine. Unlike other studies, our results demonstrated genotoxicity induced by both cotinine and nicotine. The similar effects observed for these two pyridine alkaloids may be due to the similarity of their structures.
可替宁是尼古丁的主要代谢产物，它在肝脏中通过一种细胞色素P450酶进行代谢。不同研究指出尼古丁会导致基因不稳定，如单链和双链DNA断裂以及微核形成，但对于可替宁的影响却知之甚少。因此，本体外研究评估了可替宁对SH-SY5Y神经母细胞瘤细胞的细胞活力和DNA损伤的影响，以及与氧化应激机制相关的遗传毒性。还与尼古丁进行了比较。使用经修复核酸内切酶（FPG、OGG1和Endo III）改良的碱性彗星试验来检测氧化的核碱基。SH-SY5Y神经元细胞在标准条件下培养，并暴露于不同浓度的可替宁和尼古丁中3小时。在MTT试验中，较高剂量的可替宁和尼古丁出现了细胞毒性。在台盼蓝试验中，两种化合物处理的细胞活力均高于80%。碱性彗星试验结果表明，用可替宁和尼古丁处理的细胞的损伤指数和频率显著增加，呈现出遗传毒性。酶改良彗星试验结果表明尼古丁诱导了DNA氧化损伤。与其他研究不同，我们的结果表明可替宁和尼古丁均诱导了遗传毒性。这两种吡啶生物碱观察到的相似效应可能是由于它们结构的相似性。
