Biology Department, Federal University of Lavras (UFLA), 37.200-000, Lavras, MG, Brazil.
Doctor in Genetics and Plant Breeding at Federal University of Lavras (UFLA), 37.200-000, Lavras, MG, Brazil.
Chemosphere. 2017 Jul;178:359-367. doi: 10.1016/j.chemosphere.2017.03.048. Epub 2017 Mar 21.
Studies that help understand the mechanisms of action of environmental pollutants are extremely important in environmental toxicology. In this context, assays using plants as models stand out for their simplicity and low performance cost. Among the plants used for this purpose, Allium cepa L. is the model most commonly applied for cytogenotoxic tests, while Lactuca sativa L., already widely used in phytotoxic investigations, has been gaining prominence in cytotoxic analyses. The present study aimed to compare the responses of A. cepa and L. sativa via macroscopic (root growth) and microscopic analyses (cell cycle and DNA fragmentation via TdT-mediated deoxy-uracil nick and labeling (TUNEL) and comet assays) after exposure of their roots to environmental pollutants with known cytogenotoxic mechanisms. Both species presented sensitive and efficient response to the applied tests after exposure to the DNA-alkylating agent Methyl Methanesulfonate (MMS), the heavy metal Cadmium, the aluminum industry waste Spent Potliner (SPL) and the herbicide Atrazine. However, they differed regarding the responses to the evaluated endpoints. Overall, A. cepa was more efficient in detecting clastogenic changes, arising from DNA breakage, while L. sativa rather detected aneugenic alterations, related to chromosome segregation in mitosis. In the tests applied to verify DNA fragmentation (comet and TUNEL assays), A. cepa presented higher sensitivity. In conclusion, both models are efficient to evaluate toxicological risks of environmental pollutants.
研究有助于理解环境污染物作用机制在环境毒理学中极为重要。在这种背景下，使用植物作为模型的测定方法因其简单性和低性能成本而引人注目。在为此目的而使用的植物中，洋葱（Allium cepa L.）是最常用于细胞遗传毒性测试的模型，而已经广泛用于植物毒性研究的莴苣（Lactuca sativa L.）在细胞毒性分析中越来越受到重视。本研究旨在比较洋葱和莴苣在暴露于具有已知细胞遗传毒性机制的环境污染物后通过宏观（根生长）和微观分析（通过 TdT 介导的脱氧尿嘧啶缺口和标记（TUNEL）和彗星分析进行细胞周期和 DNA 片段化）的反应。两种物种在暴露于 DNA 烷化剂甲磺酸甲酯（MMS）、重金属镉、铝工业废物废坩锅衬里（SPL）和除草剂莠去津后，对应用的测试均表现出敏感和有效的反应。然而，它们对评估终点的反应不同。总体而言，洋葱在检测由 DNA 断裂引起的断裂变化方面更为有效，而莴苣则检测到与有丝分裂中染色体分离有关的非整倍体改变。在应用于验证 DNA 片段化的测试（彗星和 TUNEL 分析）中，洋葱表现出更高的灵敏度。总之，这两种模型都可有效地评估环境污染物的毒理学风险。
