The Mechanism of Aerobic Exercise Regulating the PI3K/Akt-mTOR Signaling Pathway Intervenes in Hippocampal Neuronal Apoptosis in Vascular Dementia Rats

Edaravone Dexborneol Alleviates Neuroinflammation by Reducing Neuroglial Cell Proliferation and Suppresses Neuronal Apoptosis/Autophagy in Vascular Dementia Rats

More and more evidence shows that the pathological mechanism of vascular dementia (VD) is closely related to oxidative stress injury, cell apoptosis, autophagy, inflammatory response, excitatory amino acid toxicity, synaptic plasticity change, calcium overload, and other processes. Edaravone dexborneol (EDB) is a new type of neuroprotective agent that can improve the neurological damage caused by an ischemic stroke. Previous studies showed that EDB has effects on synergistic antioxidants and induces anti-apoptotic responses. However, it remains unclear whether EDB can affect apoptosis and autophagy by activating the PI3K/Akt/mTOR signaling pathway and its impact on the neuroglial cells. In this study, we established the VD model of rats by bilateral carotid artery occlusion to explore the neuroprotective effect of EDB and its mechanism. Morris Water Maze test was applied to assess the cognitive function of rats. H&E and TUNEL staining were applied to observe the cellular structure of the hippocampus. Immunofluorescence labeling was used to observe the proliferation of astrocytes and microglia. ELISA was applied to examine the levels of TNF-α, IL-1β and IL-6, and RT-PCR was applied to examine their mRNA expression levels. Western blotting was applied to examine apoptosis-related proteins (Bax, Bcl-2, Caspase-3), autophagy-related proteins (Beclin-1, P62, LC3B), PI3K/Akt/mTOR signaling pathway proteins and their phosphorylation levels. The results indicated that EDB ameliorates learning and memory in rats subjected to the VD model, alleviates neuroinflammatory response by reducing the proliferation of the neuroglial cell and inhibits apoptosis and autophagy, which may be mediated by the PI3K/Akt/mTOR signaling pathway.

Gastrodin relieves cognitive impairment by regulating autophagy via PI3K/AKT signaling pathway in vascular dementia

Vascular dementia (VaD), the second most common type of dementia, is attributed to lower cerebral blood flow. To date, there is still no available clinical treatment for VaD. The phenolic glucoside gastrodin (GAS) is known for its neuroprotective effects, but the role and mechanisms of action on VD remains unclear. In this study, we aim to investigate the neuroprotective role and underlying mechanisms of GAS on chronic cerebral hypoperfusion (CCH)-mediated VaD rats and hypoxia-induced injury of HT22 cells. The study showed that GAS relieved learning and memory deficits, ameliorated hippocampus histological lesions in VaD rats. Additionally, GAS down-regulated LC3II/I, Beclin-1 levels and up-regulated P62 level in VaD rats and hypoxia-injured HT22 cells. Notably, GAS rescued the phosphorylation of PI3K/AKT pathway-related proteins expression, which regulates autophagy. Mechanistic studies verify that YP-740, a PI3K agonist, significantly resulted in inhibition of excessive autophagy and apoptosis with no significant differences were observed in the YP-740 and GAS co-treatment. Meantime, we found that LY294002, a PI3K inhibitor, substantially abolished GAS-mediated neuroprotection. These results revealed that the effects of GAS on VaD are related to stimulating PI3K/AKT pathway-mediated autophagy, suggesting a potentially beneficial therapeutic strategy for VaD.