Figure 3

Increased superoxide generation from NADPH oxidase is responsible for high-cholesterol-induced endothelial dysfunction and is prevented by onion ingredient. Effects of the superoxide dismutase analogue, TEMPOL (10 μM), and the NADPH oxidase inhibitor, apocynin (APOC; 10 μM) on endothelium-dependent relaxation induced by exposure to acetylcholine (ACh; 1 nM to 30 μM) in noradrenaline (NA)-contracted rat mesenteric arteries collected from rats fed the control diet (A), rats fed the high-cholesterol diet (HC) (B) and rats fed the high-cholesterol enriched with onion diet (HCO) (C). Data are expressed as the mean ± SEM of the percentage of the remaining NA-induced contraction. n indicates the number of vascular segments used for the experiments obtained from 4–5 rats. ***P < 0.001 vs. control by a two-factors ANOVA test. Panel D shows determination of superoxide anions generated from NADPH oxidase by lucigenin-derived chemiluminiscence in mesenteric arteries collected from rats fed the control, HC and HCO diets. Data are expressed as mean ± SEM of relative light units (RLU)/mg of protein/min corresponding to 3 to 5 experiments. *P < 0.05, ***P < 0.001 vs. control group, †P < 0.05 vs. HC group by a one-way ANOVA followed by Student-Newman-Keuls test.