Figure 4. MET decreases oxidative stress in aging mice. (A) Cardiac MDA and GSH levels were quantified using commercial assay kits. n = 8 per group. *P < 0.05. (B) Cardiac NRF2, HO-1, SOD, and NOX4 levels assessed by western blotting. (C) Quantification of relative protein expression levels. (D) Representative immunohistochemistry for NRF2, HO-1, SOD, and NOX4 in cardiac tissues. (E) Quantification of positive expression. Magnification 40×. The arrows indicate positively stained cells. n = 6–8 per group. *P < 0.05.