Low dose ionizing radiation (LDIR) may trigger oxidative stress which leads to generation of free radicals. There is lack of information about the capability of watermelon
as a natural antioxidant that helps to scavenge LDIR-induced free radicals. This study was conducted to determine the radioprotective properties of 50% watermelon juice on biochemical and molecular changes against LDIR-induced oxidative stress in mice lung.
A total of 18 ICR male mice were randomly divided into three groups (n=6); negative control group, radiation group and treatment group. Mice in negative control and radiation group were given filtered tap water while treatment group was supplemented with 50%
watermelon juice for 14 days ad libitum. Mice in radiation and treatment group were then exposed to 100 µGy x-ray whole body irradiation on day 15. Liver tissues were excised
immediately and assessed for the superoxide dismutase (SOD) activity (inhibition %), total glutathione (GSH), malondialdehyde (MDA) and DNA damage (Comet Assay).
SOD activity (inhibition %) showed no significant difference between all groups. Treatment group showed increment SOD activity (inhibition %) compared to negative
control and radiation group. GSH level in lung tissues showed significant diminish in radiation group versus negative control group (p < 0.001). Treatment group showed significant depletion in GSH level compared to negative control group (p < 0.001). MDA levels showed significant increment in treatment group compared to negative control group (p < 0.005). DNA damage of lung tissues in radiation group showed significant increased compared to negative control (p < 0.001). While treatment group showed significant decreased in DNA damage compared to radiation group (p < 0.001). In conclusion, this finding may postulate that radioprotective properties of 50% watermelon juice against LDIR-induced oxidative stress which supplemented to the mice for 14 days
may reduce DNA damage but may be not give sufficient enough effect to biochemical changes in lung tissue
