Metformin alleviates neurocognitive impairment in aging via activation of AMPK/BDNF/PI3K pathway

Slowing down age-related neurocognitive impairment has been a challenge. We evaluated the therapeutic effects of metformin in d-galactose-induced aging. Additionally, we studied the potential molecular mechanisms that could be responsible for metformin's anti-aging effects. Thirty male rats were equally divided into: 1-control group, which received saline solution, 2-d-galactose (D-gal) group, which received d-galactose (100 mg/kg/day) by gastric lavage for eight weeks, and 3-d-galactose + Metformin (D-gal + Met) treated group, which received d-galactose + metformin (200 mg/kg/day) by gastric lavage for eight weeks. Neurocognitive assessment was done. Measurement of inflammatory, oxidative stress, and BDNF biomarkers was performed. AMPK and PI3K genes expression were assessed. Hippocampal tissues were dissected for histopathological and immunohistochemical studies. D-gal resulted in neurocognitive impairments, elevation of inflammatory biomarkers, altered oxidative stress markers, decreased BDNF, decreased expression of synaptophysin and Bcl2 with increased expression of Caspase-3, and down-regulation of AMPK and PI3K genes. Neurodegenerative changes were present in the hippocampus. Metformin restored significantly D-gal induced neurodegenerative changes. We concluded that metformin could alleviate age-induced neurocognitive deficit via amelioration of neuroinflammation, attenuation of oxidative stress, reduction of apoptosis, as well as promotion of synaptic plasticity. These mechanisms could be mediated via the activation of the AMPK/BDNF/PI3K pathway.