Etomidate ameliorates Alzheimer-like neuropathology and cognitive impairment in APP/PS1 mice

To investigate the effect and mechanism of etomidate on attenuating Alzheimer-like neuropathology and cognitive impairment in mice with Alzheimer's disease (AD). AD was modeled in vivo using amyloid precursor protein/presenilin 1 (APP/PS1) mice. After etomidate treatment, behavioral experiments and histopathological observation of hippocampus were performed. Hippocampal Aβ deposition was detected using immunofluorescence. AD was modeled in vitro using a HT22 cells which are an immortalized cell line derived from primary mouse hippocampal neurons induced by Aβ1-42. Cell viability, apoptosis rate and LDH release were detected after etomidate intervention. Synaptic proteins were detected by mmunofluorescence or Western blot, and neurotransmitters and inflammatory factors were detected by ELISA. Etomidate improved the memory ability, novel object cognition ability, and spatial learning of APP/PS1 mice. The improvement of cognitive function and memory ability may be due to the recovery effect of etomidate on hippocampal pathological changes in APP/PS1 mice, including reducing Aβ deposition, neuron and synaptic loss. Etomidate also regulated neuroinflammation and the release of neurotransmitters GABA and 5-HT in APP/PS1 mice. Etomidate effectively reversed Aβ1-42-induced hippocampal neuronal damage, which was reflected in the improvement of cell viability and the inhibition of cytotoxicity, apoptosis and pro-inflammatory factors. Etomidate reversed the inhibition of the expression of synaptophysin (SYP) and postsynaptic density protein-95 (PSD-95) induced by Aβ1-42 in vitro. After etomidate intervention, the expression of serotonin 1A receptor (5HT1A) and gamma-aminobutyric acid type A receptor subunit alpha1 (GABRA1) in Aβ1-42-injured HT22 cells were up-regulated, and free calcium ion was increased. In conclusion, etomidate ameliorates Alzheimer-like neuropathology and cognitive impairment in APP/PS1 mice, indicating that etomidate may be a potentially useful drug for the treatment of AD.