Cocoa Shell Extract Restores Redox Balance in Developmental Hypertension in Male Rats: Roles of Nrf2, SOD2 and p-eNOS.

Abstract

Background and objectives: Hypertension is a worldwide burden, for which fetal malnutrition is a risk factor. Another societal challenge is environmental waste. Our research focusses on cocoa shell extract (CSE), a cocoa by-product with antioxidant bioactive components. Male rats exposed to fetal malnutrition develop hypertension and endothelial dysfunction, which are improved by CSE supplementation. We hypothesized that effects of CSE are related to an antioxidant action. Methods: Adult male and female offspring of dams exposed to 50% food restriction during gestation (MUN) and controls were supplemented for 3 weeks with CSE (250 mg/kg/day) or a vehicle. We assessed plasma SOD activity, GSH and carbonyls (via spectrophotometry) and aortic expression of enzymes related to ROS degradation or production (via Western blotting). Results: MUN males showed lower Nrf2 expression and increased carbonyls, SOD activity and mitochondrial SOD2 expression, without alterations in GSH or the related enzyme CGLM. No changes in xanthine oxidase or NADPH subunits (p22phox and p47phox) were detected, suggesting a different origin of superoxide anion. Phosphorylated-eNOS/eNOS and 3-nitrotyrosine expression were increased without changes in plasma nitrates. MUN females only showed plasma SOD and aortic 3-nitrotyrosine elevation. CSE supplementation reduced SOD2 and p-eNOS/eNOS expression and SOD activity and increased Nrf2 expression. Conclusions: MUN arteries exhibit oxidative damage, with a higher impact on males. SOD2 and p-eNOS/e-NOS overexpression may be a counteracting mechanism that compensates for superoxide anion overproduction, likely involving mitochondria. The reversal of these alterations by CSE supplementation is probably related to a reduction in vascular superoxide anion through a direct scavenging action of its bioactive components. A longer supplementation period may be needed to increase endogenous antioxidants through Nrf2 and to reduce oxidative-nitrosative damage.