Antioxidant Properties of Egg White Hydrolysate Prevent Mercury-Induced Vascular Damage in Resistance Arteries

ROS Suppression by Egg White Hydrolysate in DOCA-Salt Rats—An Alternative Tool against Vascular Dysfunction in Severe Hypertension

This study aimed to evaluate the potential for lowering blood pressure and beneficial effects on mesenteric resistance arteries (MRA) and conductance vessels (aorta) produced by dietary supplementation of an egg white hydrolysate (EWH) in rats with severe hypertension induced by deoxycorticosterone plus salt treatment (DOCA-salt), as well as the underlying mechanisms involved. The DOCA-salt model presented higher blood pressure, which was significantly reduced by EWH. The impaired acetylcholine-induced relaxation and eNOS expression observed in MRA and aorta from DOCA-salt rats was ameliorated by EWH. This effect on vessels (MRA and aorta) was related to the antioxidant effect of EWH, since hydrolysate intake prevented the NF-κB/TNFα inflammatory pathway and NADPH oxidase-induced reactive oxygen species (ROS) generation, as well as the mitochondrial source of ROS in MRA. At the plasma level, EWH blocked the higher ROS and MDA generation by DOCA-salt treatment, without altering the antioxidant marker. In conclusion, EWH demonstrated an antihypertensive effect in a model of severe hypertension. This effect could be related to its endothelium-dependent vasodilator properties mediated by an ameliorated vessel’s redox imbalance and inflammatory state.

Potential benefits of egg white hydrolysate in the prevention of Hg-induced dysfunction in adipose tissue

Aim: To investigate the effects of egg white hydrolysate (EWH) on the lipid and glycemic metabolism disruption in the white adipose tissue (WAT) dysfunction induced by mercury (Hg). Experimental: Wistar rats were treated for 60 days: control (saline, intramuscular - i.m.); hydrolysate (EWH, gavage, 1 g kg^-1 day^-1); mercury (HgCl₂, i.m., 1^st dose 4.6 μg kg^-1, subsequent doses 0.07 μg kg^-1 day^-1) and hydrolysate-mercury (EWH-HgCl₂). Hg level and histological analyses were performed in epididymal WAT (eWAT), pancreas and liver. GRP78, CHOP, PPARα, PPARγ, leptin, adiponectin, and CD11 mRNA expressions were analyzed in eWAT. The plasma lipid profile, glucose, and insulin levels were measured. Antioxidant status was also evaluated in the plasma and liver. Results: EWH intake prevented the reduced eWAT weight, adipocyte size, insulin levels, and antioxidant defenses and the increased glucose and triglyceride levels induced by Hg exposure; hepatic glutathione levels were higher in rats co-treated with EWH. The increased mRNA expression of CHOP, PPARα, and leptin induced by Hg was reduced in co-treated rats. EWH did not modify the elevated mRNA expression of GRP78, PPARγ and adiponectin in Hg-treated rats. Increased levels of Hg were found in the liver; the co-treatment did not alter this parameter. EWH prevented the morphological and metabolic disorder induced by Hg, by improving antioxidant defenses, inactivating pro-apoptotic pathways and normalizing the mRNA expression of PPARs and adipokines. Its effects enabled an increase in insulin levels and a normal balance between the fat storage and expenditure mechanisms in WAT. Conclusions: EWH may have potential benefits in the prevention and management of Hg-related metabolic disorders.