The Effect of Lycopene on DNA Damage and Repair in Fluoride-Treated NRK-52E Cell Line Sedat Çetin 1 & Ayşe Usta 2 & Veysel Yüksek 3 Received: 18 May 2020 /Accepted: 10 July 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Exposure of fluorine at toxic concentrations causes serious damage by accumulating in especially bones, kidneys, and other soft tissues. Fluorine at cytotoxic concentrations may cause DNA damage. This study aims to determine the level of DNA damage due to sodium fluoride (NaF) at different hours (3rd, 12th, and 24th hours) and in IC 50 concentrations designated for each hour and reveal the protective effect of lycopene on possible damage. The best enhancer concentrations (1 μM) of microtitration (MTT) viability test and proliferation of lycopene and IC 50 values of NaF at the 3rd, 12th, and 24th hour were 9600, 5500, and 3200 μM, respectively. DNA damage significantly increased in all NaF-treated groups in comparison with the control group (p < 0.05). DNA damage due to NaF+LYC application significantly decreased in comparison with the control group (p < 0.05). Lycopene application significantly increased the expression levels of the Ku70 and Ku80 genes which have a part in DNA repair (p < 0.05). The statistical data showed that application of lycopene which is an important antioxidant molecule may be beneficial for decreasing NaF-induced DNA damage. In conclusion, applying lycopene for cytotoxicity due to fluorine in NRK-52E cell line had different effects based on the dosage and time; thus, it can be a potential option for preventing fluorosis-induced toxicity and developing new treatment approaches. Keywords NaF . DNA damage . Lycopene . DNA repair Introduction Fluorine (F) is an element with high electronegativity that can naturally be found in water and various nutrients. F is neces- sary for the normal care of tooth and bones. However, long- term exposure at high concentrations may damage the teeth, bones, and kidney [1, 2]. Fluoride has a high penetrative abil- ity and can easily penetrate the cell membrane. It may enter deeper soft tissues such as the liver, brain, and kidney, and therefore, nephrotoxicity could occur due to accumulation and retention of inorganic fluoride in the renal tubules [3]. Sodium fluoride (NaF) has different cellular effects based on time, concentration, and cell type. The main toxic effect of fluoride occurs in cells that interact with its enzymes. In most cases, fluoride acts as an enzyme inhibitor, but fluoride ions may stimulate enzyme activity from time to time. Mechanisms are based on the type of enzyme that is affected [4]. Fluoride on micromole levels is considered an effective structural agent be- cause it increases cell generation and stops enzymes such as live and inanimate phosphates with millimolar concentrations [5]. Lycopene (LYC) is a pigment from the carotene family (a carotenoid), and it is naturally abundant in many fruits and vegetables, especially red fruits such as tomatoes and water- melons [6]. Chromophore in the pollen chain gives red color to the molecule and provides antioxidant properties [7]. Since LYC has a protective effect against prostate, uterus and liver cancer, aging, Alzheimer, and cardiovascular diseases, it has various usage areas [8, 9]. DNA repair genes play an important role in protecting geno- mic integrity and preventing cells from DNA damage. The most important ways include single-strand damage repair and double- strand break (DSB) repair [10]. DNA chromosomal DSBs are potentially the most dangerous DNA lesions, and they should be repaired correctly to successfully maintain and spread genetic information. Ku heterodimers (Ku70/Ku 80) are the main com- ponent of the non-homologous end-joining (NHEJ) method of * Sedat Çetin sedatcetin@yyu.edu.tr 1 Faculty of Veterinary Medicine, Biochemistry Department, Van Yuzuncu Yil University, Van, Turkey 2 Faculty of Science, Chemistry Department, Van Yuzuncu Yil University, Van, Turkey 3 Özalp Vocational High School, Van Yuzuncu Yil University, Van, Turkey Biological Trace Element Research https://doi.org/10.1007/s12011-020-02288-4