Protective effect of notoginsenoside R1 on an APP/PS1 mouse model of Alzheimer's disease by up-regulating insulin degrading enzyme and inhibiting Aβ accumulation

This study aimed at exploring the anti-AD effects of Notoginsenoside R1 (NTR1) ​ in APP/PS1 Tg AD mice. Notoginsenoside R1 (NTR1) is the unique and main active ingredient of Panax notoginseng a well-known traditional Chinese herbal medicine which has been widely used for diseases related to the circulatory system, such as cardio- and cerebro-vascular disorders, and liver dysfunction.  The study found that mice treated with NTR1, showed significant amelioration in  cognitive function and increased choline acetyl transferase expression, as compared to the vehicle treated mice. NTR1 treatment inhibited Aβ accumulation and increased insulin degrading enzyme (IDE) expression in APP/PS1 mice, the latter suggests that NTR1 may exert its protective effects through the enhancement of the Aβ degradation. Data showed that the increased level of peroxisome proliferator-activated receptor γ (PPARγ) and the up-regulation of insulin degrading enzyme induced by NTR1 were inhibited by administration of GW9662 (a PPARγ antagonist), indicating that the effect of NTR1 was mediated, at least in part, by PPARγ.  These findings demonstrate that NTR1 has protective effect on AD mouse model and suggest that NTR1 may be a potential candidate for AD treatment.