First Assessment of Genetic Damage in the Speckled Cockroach ( Nauphoeta cinerea ) After Consumption of Lettuce ( Lactuca sativa ) Cultivated and Commercialized in Northeastern, Brazil

This study reports, for the first time, the use of the speckled cockroach Nauphoeta cinerea as a promising bioindicator for genotoxic monitoring. It was validated through control groups (both positive and negative) in addition to testing lettuce (Lactuca sativa ) samples from public street markets consumed by N. cinerea specimens in Pernambuco, Northeastern Brazil. N. cinerea nymphs were fed with lettuce samples for 48 h. A negative control group received fish feed hydrated in distilled water, while a positive control was exposed to cyclophosphamide 2 mg/mL within the feed. DNA damage was assessed through two independent experiments using the comet assay on hemolymph cells; results were classified on a scale from 0 to 4 and quantified using Damage Index and Damage Frequency. After exposure and comet assay performance, the hemocytes of N. cinerea demonstrated significant DNA damage within all samples consumed, including the positive control, suggesting the good sensibility of the model and the potential presence of genotoxic compounds on the crop samples. N. cinerea appeared as a sensitive bioindicator for the assessment of DNA damage, offering a novel and potentially valuable tool for assessing a variety of stressors on the DNA. Our findings indicate potential risks associated with lettuce consumption by non-human organisms. Additionally, further investigations integrating water, soil and the vegetable itself are encouraged to verify potentially toxic elements in the crop.