Abstract
BackgroundReactive oxygen species (ROS) mediate much of the DNA damage caused by ionizing radiation. Among carotenoids, lycopene and β-carotene, present in tomato juice, are known to be strong radical scavengers. The aim of the study was to investigate the effect of tomato juice intake on the levels of DNA damage and oxidative stress in human whole blood induced by in vitro exposure to X-rays.MethodsTen healthy adults were asked to drink 190 g of tomato juice, containing 17 mg lycopene and 0.25 mg β-carotene, per day for 3 weeks and then refrain from drinking it for 3 weeks. Peripheral whole blood samples were collected before and after the intake period of tomato juice and after the washout period. The blood samples were exposed in vitro to X-ray doses of 0, 0.1, 0.5, and 2 Gy. Cytogenetic damage was measured using the cytokinesis-block micronucleus (CBMN) assay and the dicentrics (DIC) assay. The level of oxidative stress was determined using serum 8-oxo-7, 8-dihydro-2-deoxyguanosine (8-oxo-dG) and plasma reactive oxygen metabolite-derived compounds (d-ROMs). The concentration of carotenoids in plasma was measured at the three time points.ResultsThe levels of 8-oxo-dG tended to decrease during the intake period and increase during the washout period. A non-significant inverse correlation was noted between the plasma concentration of lycopene plus β-carotene and the level of 8-oxo-dG (P = 0.064). The radiation-induced MN and DIC frequencies increased in a dose-dependent manner, and when compared at the same dose, the MN and DIC frequencies decreased during the intake period compared with those at baseline and then increased during the washout period. The results suggest that continuous tomato juice consumption non-significantly decreases extracellular 8-oxo-dG, d-ROMs, and MN. Tomato juice intake had minimal or no effect on radiation-induced 8-oxo-dG and d-ROMs. For most radiation doses, continuously tomato juice intake lowered the levels of MN and DIC.ConclusionTomato juice consumption may suppress human lymphocyte DNA damage caused by radiation, but further examination is required.Trial registration2014-001 and 2014-R06.
Highlights
Reactive oxygen species (ROS) mediate much of the DNA damage caused by ionizing radiation
The plasma levels of six major carotenoids at the three different time points are shown in Table 2, and the sum of the concentrations of lycopene and β-carotene in tomato juice was calculated
The plasma concentration of lycopene significantly increased after 3 weeks of tomato juice intake (0.51 ± 0.03 μg/mL) compared with that at the baseline level (0.34 ± 0.03 μg/mL) and reduced to the baseline level after the washout period (0.34 ± 0.03 μg/mL)
Summary
Reactive oxygen species (ROS) mediate much of the DNA damage caused by ionizing radiation. The aim of the study was to investigate the effect of tomato juice intake on the levels of DNA damage and oxidative stress in human whole blood induced by in vitro exposure to X-rays. ROS react with biomolecules in vivo, resulting in lipid peroxidation, DNA damage, and protein modification. ROS are produced during cellular metabolism and give rise to DNA damage and protein/lipid modifications. X-rays cause DNA damage directly by inducing ionization and excitation of DNA molecules and indirectly through the formation of ROS by radiolysis of cellular water molecules. In addition to the level of ROS formed by the radiolysis of cellular water, ionizing radiation increases the endogenous production of free radicals from e.g., mitochondria [4, 5]. The aberrations can be measured in the form of dicentrics (DIC) formed as result of mis-repaired double strand breaks [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
