Ligustilide ameliorates cognitive impairment via AMPK/SIRT1 pathway in vascular dementia rat.

Vascular dementia (VaD) is the second cause of dementia after Alzheimer's disease. Ligustilide (LIG) is one of the main active ingredients of traditional Chinese medicines, such as Angelica. Studies have reported that LIG could protect against VaD. However, the mechanism is still confused. In this study, we employed a bilateral common carotid artery occlusion rat model to study. LIG (20 or 40 mg/kg/day) and Nimodipine (20 mg/kg) were orally administered to the VaD rats for four weeks. Morris water maze test showed that LIG effectively ameliorated learning and memory impairment in VaD rats. LIG obviously reduced neuronal oxidative stress damage and the level of homocysteine in the brain of VaD rats. Western blot results showed that pro-apoptotic protein Bax and cleaved caspase 3 increased and anti-apoptotic protein Bcl-2 decreased in the hippocampi of VaD rats. But after LIG treatment, these changes were reversed. Moreover, Nissl staining result showed that LIG could reduce neuronal degeneration in VaD rats. Furthermore, LIG enhanced the expressions of P-AMPK and Sirtuin1(SIRT1) in VaD rats. In conclusion, these studies indicated that LIG could ameliorate cognitive impairment in VaD rats, which might be related to AMPK/SIRT1 pathway activation.

Quercetin improves cognitive disorder in aging mice by inhibiting NLRP3 inflammasome activation.

Quercetin is one of the most abundant dietary flavonoid compounds, and its mechanism for combating age-related neurodegenerative diseases is unclear. In this study, quercetin (35 and 70 mg kg-1, orally administered for 4 weeks) was administered to 7-month-old aging mice (senescence-accelerated mouse prone 8 mice). As a result, it was found that quercetin could improve spatial learning and memory impairment displayed by aging mice in the Morris water maze. The results of immunoblotting reflected the protein expressions of the longevity factor (sirtuin1), inflammasomes (NLRP3 and ASC), synaptic marker (PSD95) and neurotrophic factors (BDNF and NGF) in the hippocampus of the brain. It indicated that the intervention of quercetin could increase the expression of sirtuin1 and prevent neuroinflammation, which was evident from the decrease in the protein levels of the astrocyte marker (GFAP) and inflammatory factors (cleaved-caspase 1, IL-1ß and IL-18). In addition, quercetin could reduce the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) in the hippocampus of aging mice. Current data indicated that quercetin might improve neuroinflammation in aging mice by regulating the Sirtuin1/NLRP3 pathway.