Scatterplot correlation matrix of OHDG (8-OHdG) (pg/mL) and GSH levels (µmol/mL) at day 0, 4, 8 and 12. The histogram on the diagonal axis shows the distribution and left lower diagonal section illustrates the density eclipses with the magnitude of linear association between variables (tighter eclipses show stronger correlation). The upper-diagonal section illustrates the significance of relationship between variables. *p < 0.05, **p < 0.01.