Low doses of methylmercury exposure during adulthood in rats display oxidative stress, neurodegeneration in the motor cortex and lead to impairment of motor skills

• Published in: Journal of trace elements in medicine and biology Vol. 51; pp. 19 - 27
• Main Authors: Santana, Luana Nazaré da Silva, Bittencourt, Leonardo Oliveira, Nascimento, Priscila Cunha, Fernandes, Rafael Monteiro, Teixeira, Francisco Bruno, Fernandes, Luanna Melo Pereira, Freitas Silva, Marcia Cristina, Nogueira, Lygia Sega, Amado, Lílian Lund, Crespo-Lopez, Maria Elena, Maia, Cristiane do Socorro Ferraz, Lima, Rafael Rodrigues
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 01-01-2019
• Subjects: Animals; Dose-Response Relationship, Drug; Male; Methylmercury Compounds - administration & dosage; Methylmercury Compounds - pharmacology; Motor Cortex - drug effects; Motor Cortex - pathology; Motor Cortex - physiopathology; Motor function; Motor Skills - drug effects; Nerve Degeneration - chemically induced; Nerve Degeneration - pathology; Neurodegeneration; Organic mercury; Organomercury compound; Oxidative stress; Oxidative Stress - drug effects; Rats; Rats, Wistar; Oxidative stress; Organic mercury; Motor function; Organomercury compound; Neurodegeneration
• ISSN: 0946-672X; 1878-3252
• DOI: 10.1016/j.jtemb.2018.09.004

Despite the vast distribution among tissues, the central nervous system (CNS) represents the main target of methylmercury (MeHg) toxicity. However, few studies have evaluated the effects of MeHg exposure on the CNS at equivalent doses to human environmental exposure. In our study, we evaluated the motor cortex, an important area of motor control, in adult rats chronically exposed to MeHg in a concentration equivalent to those found in fish-eating populations exposed to mercury (Hg). The parameters evaluated were total Hg accumulation, oxidative stress, tissue damage, and behavioral assessment in functional actions that involved this cortical region. Our results show in exposed animals a significantly greater level of Hg in the motor cortex; increase of nitrite levels and lipid peroxidation, associated with decreased antioxidant capacity against peroxyl radicals; reduction of neuronal and astrocyte density; and poor coordination and motor learning impairment. Our data showed that chronic exposure at low doses to MeHg is capable of promoting damages to the motor cortex of adult animals, with changes in oxidative biochemistry misbalance, neurodegeneration, and motor function impairment.