OBJECTIVETo explore the effect of Panax notoginseng saponin (PNS) on the activity and content of beta-secretase in the brain of senescence accelerated mouse-prone 8 (SAMP8) mice with Alzheimer's disease.

METHODSTotally 32 SAMP8 mice were randomly divided into the normal control group, the high dose PNS group (200 mg/kg), the low dose group (100 mg/kg), and the huperzine A group (0.3 mg/kg), 8 in each group. Equal volume of double distilled water was given to those in the normal control group. All medication was given by gastrogavage, once daily for two successive months. The activity of BACE1 was assayed by direct immunofluorescent method (DIF). The content of BACE1 protein was detected by Western blot.

RESULTSThe relative fluorescence units (RFU/microg) was 2.008 +/- 0.031 in the high dose PNS group, 2.221 +/- 0.029 in the low dose PNS group, and 2.267 +/- 0.076 in the huperzine A group, all lower than that in the normal control group (2.403 +/- 0.058; all P < 0.01). The content of BACE1 protein was 0.900 +/- 0.028 in the high dose PNS group, 1.000 +/- 0.032 in the low dose PNS group, and 0.837 +/- 0.080 in the huperzine A group, all lower than that in the normal control group (2.210 +/- 0.074, all P < 0.01).

CONCLUSIONPNS higher than 100 mg/kg could decrease the activity of BACE1 and down-regulate the content of BACE1 protein in the brain of SAMP8 mice.