AD-1 Small Molecule Improves Learning and Memory Function in Scopolamine-Induced Amnesic Mice Model through Regulation of CREB/BDNF and NF-κB/MAPK Signaling Pathway.

Cognitive decline and memory impairment induced by oxidative brain damage are the critical pathological hallmarks of Alzheimer's disease (AD). Based on the potential neuroprotective effects of AD-1 small molecule, we here explored the possible underlying mechanisms of the protective effect of AD-1 small molecule against scopolamine-induced oxidative stress, neuroinflammation, and neuronal apoptosis. According to our findings, scopolamine administration resulted in increased AChE activity, MDA levels, and decreased antioxidant enzymes, as well as the downregulation of the antioxidant response proteins of Nrf2 and HO-1 expression; however, treatment with AD-1 small molecule mitigated the generation of oxidant factors while restoring the antioxidant enzymes status, in addition to improving antioxidant protein levels. Similarly, AD-1 small molecule significantly increased the protein expression of neuroprotective markers such as BDNF and CREB and promoted memory processes in scopolamine-induced mice. Western blot analysis showed that AD-1 small molecule reduced activated microglia and astrocytes via the attenuation of iba-1 and GFAP protein expression. We also found that scopolamine enhanced the phosphorylation of NF-κB/MAPK signaling and, conversely, that AD-1 small molecule significantly inhibited the phosphorylation of NF-κB/MAPK signaling in the brain regions of hippocampus and cortex. We further found that scopolamine promoted neuronal loss by inducing Bax and caspase-3 and reducing the levels of the antiapoptotic protein Bcl-2. In contrast, AD-1 small molecule significantly decreased the levels of apoptotic markers and increased neuronal survival. Furthermore, AD-1 small molecule ameliorated scopolamine-induced impairments in spatial learning behavior and memory formation. These findings revealed that AD-1 small molecule attenuated scopolamine-induced cognitive and memory dysfunction by ameliorating AChE activity, oxidative brain damage, neuroinflammation, and neuronal apoptosis.