Tanshinone IIA attenuates Aβ_25–35-induced spatial memory impairment via upregulating receptors for activated C kinase1 and inhibiting autophagy in hippocampus

Abstract

Objectives

Tanshinone IIA (Tan IIA) may exert significant protective effects against the neurotoxicity induced by β-amyloid protein (Aβ). This study was designed to investigate the possible neuroprotective mechanism of Tan IIA on Aβ_25–35-induced spatial memory impairment in mice.

Methods

After 3 weeks of preventive treatment (Tan IIA or oil), all male Kunming mice were subjected to Aβ_25–35 (10 μl, intracerebroventricularly (i.c.v.)) to establish the spatial memory impairment model. The Morris water maze (MWM), haematoxylin and eosin staining, real-time PCR and Western blot were performed to determine the ability of spatial memory, neuronal damage and expression of extracellular signal-regulated kinase (ERK), receptors for activated C kinase1 (RACK1) and autophagy-related genes. Additionally, ShRACK1 was used to decrease the level of RACK1 in the hippocampus to test Beclin1 in hippocampus by real-time PCR and Western blot.

Key findings

Tanshinone IIA (Tan IIA, 80 mg/kg) administration notably protected mice from Aβ_25-35-induced spatial memory impairment and neurotoxicity, increased pERK/ERK and the expression of RACK1, and reduced the elevated levels of BECLIN1 and LC3-II/I in the hippocampus. In addition, ShRACK1 i.c.v markedly upregulated BECLIN1 level, but not altered Beclin1 mRNA expression in the hippocampus.

Conclusions

Tanshinone IIA may exert neuroprotective effects via upregulating RACK1 and inhibiting autophagy in the hippocampus of mice.

autophagy, Aβ_25–35, receptors for activated C kinase1, spatial memory impairment, Tanshinone IIA