The synergistic effect of paraquat dichloride, iron (II), and lead (II) on DNA adduct 8-OHdG formation: An in vitro study

This in vitro study aims to detect the formation of DNA adduct 8-OHdG (8-hydroxy-2'-deoxyguanosine), one of the biomarkers of DNA damage, and to confirm the synergistic effect of xenobiotic exposure of paraquat dichloride and heavy metals such as Fe(II) and Pb(II). This study was done by reacting 2'-deoxyguanosine as one of the DNA bases with H2O2, paraquat dichloride, Fe(II), and Pb(II) through Fenton and Fenton-like reactions. Each sample was treated equally in the variations of pH 7.4 and 8.4 and was incubated for 24 hours at a temperature of 37°C. The 8-OHdG formation analysis was conducted by using reverse-phase HPLC with a ultraviolet-visible (UV-visible) detector and the mobile phase was buffer solution of natrium phosphate 10 mM pH 6.7 with methanol (85:15). This study found that paraquat can interact with 2'-deoxyguanosine base and induce the formation of 8-OHdG. Fe(II) and Pb(II) exhibited a synergistic effect with paraquat dichloride, as indicated by the increase in 8-OHdG concentration when the metals were added. This study showed that paraquat dichloride, Fe(II), and Pb(II) contribute to the formation of ROS and a higher 8-OHdG concentrations. In addition, pH level also appears to affect the 8-OHdG formation, proven by the higher 8-OHdG concentration in samples with pH 8.4when compared to samples with pH 7.4.