Fig. 4.

MEL treatment to rats with chronic GWI reduced oxidative stress, improved antioxidant status and mitochondrial function in the hippocampus. The bar charts in A-E compare the concentration of malondialdehyde (MDA; A), protein carbonyls (PCs; B), the nuclear factor erythroid 2–related factor 2 (NRF2; C), catalase (CAT; D), and glutathione (GSH; E) in the hippocampus between naïve, and GWI rats receiving vehicle (GWI-Veh) or different doses of MEL (GWI-MEL10-80 groups). Note that MDA and PCs were upregulated, and NRF2 and CAT were downregulated in the GWI-Veh group, compared to the naïve control group. In all GWI-MEL groups, MDA and PCs were reduced compared to the GWI-Veh group. NRF-2 and CAT levels in the GWI-MEL20-80 groups were normalized to the naïve control level, whereas the GSH concentration in the GWI-MEL10-80 groups increased above the level seen in both naïve and GWI-Veh groups. The bar charts in F–I compare the concentration of mitochondrial complexes I-IV in the hippocampus between different groups. All complexes were reduced in the GWI-Veh group compared to the naïve control group. The complex I (F) and II (G) were normalized to the naïve control level in the GWI-MEL80 group, and the complex III (H) was normalized to the naïve control level in the GWI-MEL10-80 groups. Figures J–R illustrate the presence of NRF-2 in the nuclei of CA3 pyramidal neurons from naïve control (J–L), GWI-Veh (M − O), and GWI-MEL80 (P–R) groups. Scale bar, 12.5 μm *, p < 0.05, **, p < 0.01, and ***, p < 0.001; NS, not significant.