Ameliorative effects of egg white hydrolysate on recognition memory impairments associated with chronic exposure to low mercury concentration

• Published in: Neurochemistry international 2016-12, Vol.101, p.30-37
• Main Authors: Rizzetti, Danize Aparecida, Altermann, Caroline Dalla Colletta, Martinez, Caroline Silveira, Peçanha, Franck Maciel, Vassallo, Dalton Valentim, Uranga-Ocio, José Antonio, Castro, Marta Miguel, Wiggers, Giulia Alessandra, Mello-Carpes, Pâmela Billig
• Format: Article
• Language: English
• Subjects: Animals; Antioxidant activity; Antioxidants - pharmacology; Egg White; Egg white hydrolysate; Lipid Peroxidation - drug effects; Male; Memory Disorders - drug therapy; Memory impairments; Mercury; Mercury - pharmacology; Oxidative stress; Oxidative Stress - drug effects; Protein Hydrolysates - metabolism; Rats, Wistar; Reactive Oxygen Species - pharmacology
• ISSN: 0197-0186; 1872-9754
• DOI: 10.1016/j.neuint.2016.10.002

The study aimed to investigate whether the Egg White Hydrolysate (EWH) is able to prevent the recognition memory disorders associated with long-term Hg exposure in rats. For this, male Wistar rats were treated for 60 days with: a) Untreated: saline solution (i.m.); b) Hydrolysate: EWH (1 g/kg/day, gavage); c) Mercury: HgCl2 (1st dose 4.6 μg/kg, subsequent doses 0.07 μg/kg/day, i.m.); d) Hydrolysate-Mercury. Object recognition memory test was performed to verify Short (STM) and Long-Term Memory (LTM) and Open Field, Plus Maze and Tail Flick tests were performed as control for behavioural experiments. Reactive Oxygen Species (ROS) in the hippocampus were determined by the dichlorofluorescein diacetate (DCFH-DA) method, malondialdehyde (MDA) levels by TBARS, antioxidant power by FRAP assay and total Hg concentration by atomic fluorescence spectrometry. We confirm that the STM and LTM were impaired in adult rats exposed to Hg at low concentrations, which may be related to the increased metal deposition, ROS production and subsequent oxidative damage in the hippocampus. In addition, we demonstrated for the first time that EWH treatment is able to prevent memory impairment induced by Hg exposure, reducing Hg content and ROS production in the hippocampus. In conclusion, EWH prevents memory impairments induced by chronic exposure to low doses of Hg. These findings may represent a good public health strategy since they indicate that EWH is a promising candidate as a new natural therapy for heavy metal intoxication. •Mercury (Hg) promotes Short- and Long-Term Memory impairments in adulthood rats.•Memory deficits appear to be related to the oxidative stress caused by the Hg.•Egg White Hydrolysate (EWH) prevents Hg-induced memory impairments.•EWH likely inhibits Hg-induced damage through its antioxidant and chelating effects.