Variability in the Content of 8-Hydroxy-2-deoxyguanosine as a Marker of Oxidative Stress during Subchronic Intoxication with Pesticides

In this study, a change in the concentration of 8-hydroxy-2-deoxyguanosine (8-OHdG) in the oral fluid and plasma of model animals (rats) during subchronic intoxication with different classes of pesticides (thiram and imidacloprid) was studied. The intake of pesticides into the organism of rats with standard feed or water at a dose of 1/50 LD₅₀ for 28 days is accompanied by the production of an excess amount of reactive oxygen species (ROS) in the oral fluid and plasma. A cessation in pesticide intake leads to an insignificant decrease in ROS but does not reach the level of intact animals. An increase in the amount of 8-OHdG during subchronic intoxication with pesticides indicates the oxidative damage to DNA. In the oral fluid, the effect of thiram is accompanied by an increase in the amount of 8-OHdG on the day 21 of intoxication and in plasma at the day 7; at the same time, the level of 8-OHdG after the cessation of intoxication decreases to the control in the oral fluid and remains excessive in plasma. Imidacloprid leads to a growth in 8-OHdG in the oral fluid and plasma during 28 days of intoxication. After the cessation of the intake after 28 days, an increased content of 8-OHdG in the oral fluid and plasma remains. Imidacloprid causes a more pronounced oxidative effect on DNA as compared with thiram, which is accompanied by higher concentrations of 8‑OHdG in biological fluids. The accumulation of 8-OHdG indicates a depletion of antioxidant and reparative systems of the organism.