Protective effects of tao-Hong-si-wu decoction on memory impairment and hippocampal damage in animal model of vascular dementia

Abstract

Tao-Hong-Si-Wu decoction (TSD) as a traditional chinese medicine (TCM) has been developed to treat thrombotic diseases for hundreds of years, and vascular dementia (VD) is a cognitive dysfunction syndrome caused by cerebral embolism. In this study, the protective effect of TSD on memory impairment and brain damage in rat model of VD induced by middle cerebral artery occlusion (MCAO) was investigated. The study showed that rats in MCAO treatment with TSD for 14 days significantly improved behavioral function, increased densities of neuron, and induced angiogenesis in the brain compared with model rats. TSD also adjusted the neurotransmitter levels, reduced the content of endothelin-1 (ET-1), and induced the activities of vascular endothelial growth factor (VEGF) in hippocampus. Moreover, the immunohistochemical staining and western blotting results also revealed that TSD decreased apoptosis via upregulated B-cell lymphoma-2 (Bcl-2)/Bcl-2 associated X protein (Bax) ratio. These results demonstrated TSD possesses neuroprotective and antidementia properties by preventing the loss of neural cells, adjusting brain neurotransmitter, promoting cerebral blood circulation, and decreasing apoptosis. These results suggested that TSD might be developed as an effective drug for the prevention of VD.

Figure 1

Performances of rats in Morris water maze tests. (a) The escapes latency of rats in training trials. (b) Percent distance in the target quadrant in probe trials. (c) Representative pathways in the last day of training trials. The smart cycle is the platform region. Data are presented as means ± S.D. ^** P < 0.01, ^* P < 0.05, compared with the sham operation group. ^## P < 0.01, ^# P < 0.05, compared with the model group, n = 12.

Figure 2

HE stains of hippocampal CA1 of brain after 14 d of MCAO. (a) Sham group; (b) model group; (c) 18 g/kg TSD; (d) 9 g/kg TSD; (e) 4.5 g/kg TSD; (f) 0.02 g/kg nimodipine. Magnification = 400.

Figure 3

The statistical analysis of the number of surviving neurons along 1 mm liner in the middle hippocampus CA1. The results are expressed as the mean ± S.D., n = 6; ^* P < 0.05, ^** P < 0.01 compared with sham operation group; ^# P < 0.05, ^## P < 0.01 compared with model group.

Figure 4

Microvessels density (MVD) in hippocampus CA1 for each group (400x magnification). (a) Immunohistochemical staining of CD34 in the ischemia area after MCAO for each group. (b) MVD was evidently increased by TSD treatment. (A) Sham group; (B) model group; (C) 18 g/kg TSD; (D) 9 g/kg TSD; (E) 4.5 g/kg TSD; (F) 0.02 g/kg nimodipine. Data were shown as mean ± S.D. (n = 6). ^* P < 0.05, ^** P < 0.01 compared with sham operation group; ^# P < 0.05, ^## P < 0.01 compared with model group.

Figure 5

Immunohistochemistry of Bcl-2 and Bax in hippocampus CA1 of MCAO rats (magnification = 400). (a(A)) Bcl-2 immunostained tissue in sham group; (a(B)) Bcl-2 immunostained tissue in model group; (a(C)) Bcl-2 immunostained tissue in 18 g/kg TSD group; (a(D)) Bcl-2 immunostained tissue in 9 g/kg TSD group; (a(E)) Bcl-2 immunostained tissue in 4.5 g/kg TSD group; (a(F)) Bcl-2 immunostained tissue in 20 mg/kg Nimodipine group. (b(A)) Bax immunostained tissue in sham group; (b(B)) Bax immunostained tissue in model group; (b(C)) Bax immunostained tissue in 18 g/kg TSD group; (b(D)) Bax immunostained tissue in 9 g/kg TSD group; (b(E)) Bax immunostained tissue in 4.5 g/kg TSD group; (b(F)) Bax immunostained tissue in 20 mg/kg nimodipine group.

Figure 6

TSD reduces Bcl-2/Bax ratio. (a) Representative protein bands from western blotting for Bax and Bcl-2 in hippocampus. 1: sham group, 2: model group, 3: 18 g/kg TSD group, 4: 9 g/kg TSD group, 5: 4.5 g/kg TSD group, and 6: nimodipine group. (b) The effect of the TSD on the expression of Bax, Bcl-2, and Bcl-2/Bax of hippocampal neurons. Blots represent one of three experiments. Data were shown as mean ± S.D. (n = 3). ^* P < 0.05, ^** P < 0.01 compared with sham operation group; ^# P < 0.05, ^## P < 0.01 compared with model group.