Selenium protection against mercury neurotoxicity: Modulation of apoptosis and autophagy in the anterior pituitary

Life Sci. 2019 Aug 15:231:116578. doi: 10.1016/j.lfs.2019.116578. Epub 2019 Jun 15.

Abstract

Aims: The aim of the present study is to shed light on the modulating action of selenium on two of the most crucial cellular pathways; apoptosis and autophagy and the possible interplay between them in determining the pituitary fate in the context of mercury intoxication through demonstration of the molecular, histopathological, immunohistochemical, and ultrastructural features of selenium mercury-treated adenohypophysis.

Methods: Thirty adult Sprague Dawley male albino rats were assigned into control group, mercury-treated group and mercury‑selenium concomitantly-treated group. The adenohypophysis was subjected to structural, molecular and protein expression assessment of autophagy and apoptotic markers and western blotted analysis of Beclin 1 as a key cross-regulator of autophagy and apoptosis.

Key findings: Selenium treatment ameliorated the mercury-induced apoptosis detected by improvement in PCR and immunohistochemical expression of the apoptotic markers Bax, Bcl-2 and Caspase-3. Selenium also improved mercury-induced autophagic dysfunction with statistically significant improvement in western blotted levels of the autophagy markers LC3I, LC3II and Beclin1. The histopathological and ultrastructural studies strongly confirmed those findings.

Significance: The crosstalk between the apoptotic Bcl-2 family of proteins and the autophagic Beclin-1LC3 pathway in the context of mercury intoxication paves the way for developing novel effective treatment strategies for several mercury-induced pituitary diseases.

Keywords: Apoptosis; Autophagy; Mercury; Selenium.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis Regulatory Proteins / metabolism
  • Autophagy / drug effects
  • Beclin-1 / metabolism
  • Caspase 3 / metabolism
  • Male
  • Mercury / toxicity*
  • Mercury Poisoning / metabolism
  • Mercury Poisoning / pathology
  • Mercury Poisoning / prevention & control*
  • Pituitary Gland / drug effects*
  • Pituitary Gland / metabolism
  • Pituitary Gland / pathology
  • Pituitary Gland, Anterior / drug effects
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Selenium / pharmacology*
  • bcl-2-Associated X Protein / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • Beclin-1
  • Becn1 protein, rat
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-2-Associated X Protein
  • Caspase 3
  • Mercury
  • Selenium