Fumonisin-containing diets decrease the metabolic activity of myenteric neurons in rats

ABSTRACT

Fumonisins are naturally occurring mycotoxins that contaminate food for human and animal consumption. They have neurotoxic effects, but the mechanisms by which these toxins affect the nervous system are not fully known. In the present study, male Wistar rats were fed between 21 and 63 days of age with diets that contained fumonisins B₁+B₂ at 0, 1, and 4 mg/kg. The following variables were assessed: food consumption, growth, body weight gain, and blood parameters. Morphoquantitave analyses of the most metabolically active myenteric neurons were performed, detected by NADH-diaphorase activity. Nitrergic neurons were detected by NADPH-diaphorase activity. The fumonisin-containing diets did not significantly alter food consumption or the body or plasma parameters. These diets decreased the metabolic activity of jejunal myenteric neurons, reducing neuronal density of the most metabolic active neurons by 30.8% and the cell body area by 4.3%. The diets also decreased the cell body area of nitrergic neurons by 22.1%. The effects of fumonisin B₁ on the respiratory metabolism of isolated mitochondria in the brain and liver were also assessed. A decrease in oxygen consumption up to a 29% in the brain and 38% in the liver was observed in mitochondrial isolates to which 50 µM fumonisin B₁ was added. The decrease in respiratory activity that was triggered by exposure to fumonisins was related to the lower metabolic activity of myenteric neurons, which had a negative impact on neuroplasticity of the enteric nervous system.

KEYWORDS:

• fumonisins
• myenteric plexus
• NADH-diaphorase
• NADPH-diaphorase
• mitochondrial dysfunction
• neuroplasticity
• neurotoxicity

Acknowledgements

We thank Dr. Paulo Dilkin from the Laboratory of Mycotoxicologic Analyses, Federal University of Santa Maria (Rio Grande do Sul, Brazil), who provided the mycotoxins that were used in this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Fernando Carlos Sousa

Fernando Carlos Sousa has a degree in Biological Sciences (2003), a master's degree (2006) and a doctorate (2013) in Cellular and Molecular Biology.

Christiano Rodrigues Schamber

Christiano Rodrigues Schamber has a degree in Biological Sciences (2004), a master's degree in Zootechnics (Nutrition of Non-Ruminant Animals) (2008) and a doctorate in Cellular and Molecular Biology (2013).

Eneri Vieira de Souza Leite Mello

Eneri Vieira de Souza Leite Mello has a degree in Pharmacy (1983), a master's degree (1995) and a doctorate (2005) in Cellular and Molecular Biology.

Fernanda Andrade Martins

Fernanda Andrade Martins has a degree in Nutrition (2008), a master's degree in Health Sciences (2011) and a doctorate in Public Health (2020).

Miguel Machinski Junior

Miguel Machinski Junior has a degree in Biochemical Pharmacy (1988), a master's degree in Toxicology and Toxicological Analysis (1994) and a doctorate in Food Science (2000).

Cleverson Busso

Cleverson Busso has a degree in Biological Sciences (2003), a master's degree in Genetics and Breeding (2005) and a doctorate in Microbiology (2010).

Mario Henrique de Barros

Mario Henrique de Barros has a degree in Biological Sciences (1993), a master's degree (1996) and a doctorate (2000) in Genetics.

Maria Raquel Marçal Natali

Maria Raquel Marçal Natali has a degree in Biological Sciences (1983), a master's degree in Cellular and Molecular Biology (1993) and a doctorate in Biological Sciences (2005).