Effects of metformin on recognition memory and hippocampal neuroplasticity in rats with metabolic syndrome

Synapse. 2020 Sep;74(9):e22153. doi: 10.1002/syn.22153. Epub 2020 Apr 6.

Abstract

Metabolic syndrome (MS) is a health problem that is characterized by body fat accumulation, hypertension, dyslipidemia, and hyperglycemia; recently, it has been demonstrated that MS also damages memory processes. The first-line drug in the treatment of MS and type 2 diabetes mellitus is metformin, which is an antihyperglycemic agent. This drug has been shown to produce neuroprotection and to improve memory processes. However, the mechanism involved in this neuroprotection is unknown. A 90-day administration of metformin improved the cognitive processes of rats with MS as evaluated by the novel object recognition test, and this finding could be explained by an increase in the neuronal spine density and spine length. We also found that metformin increased the immunoreactivity of synaptophysin, sirtuin-1, AMP-activated protein kinase, and brain-derived neuronal factor, which are important plasticity markers. We conclude that metformin is an important therapeutic agent that increases neural plasticity and protects cognitive processes. The use of this drug is important in the minimization of the damage caused by MS.

Keywords: Golgi-Cox; plasticity; sirtuin-1; spines dendritic; synaptophysin.

MeSH terms

  • AMP-Activated Protein Kinase Kinases
  • Animals
  • Brain-Derived Neurotrophic Factor / metabolism
  • Hippocampus / drug effects*
  • Hippocampus / metabolism
  • Hippocampus / physiology
  • Hypoglycemic Agents / administration & dosage
  • Hypoglycemic Agents / pharmacology*
  • Hypoglycemic Agents / therapeutic use
  • Male
  • Metabolic Syndrome / drug therapy
  • Metabolic Syndrome / metabolism
  • Metabolic Syndrome / physiopathology*
  • Metformin / administration & dosage
  • Metformin / pharmacology*
  • Metformin / therapeutic use
  • Neuronal Plasticity*
  • Neuroprotective Agents / administration & dosage
  • Neuroprotective Agents / pharmacology*
  • Neuroprotective Agents / therapeutic use
  • Protein Kinases / metabolism
  • Rats
  • Rats, Wistar
  • Recognition, Psychology*
  • Sirtuin 1 / metabolism
  • Synaptophysin / metabolism

Substances

  • Brain-Derived Neurotrophic Factor
  • Hypoglycemic Agents
  • Neuroprotective Agents
  • Synaptophysin
  • Metformin
  • Protein Kinases
  • AMP-Activated Protein Kinase Kinases
  • Sirtuin 1