[Prevention of vascular dementia. Evidence and practice]

(2R,3S)-Pinobanksin-3-cinnamate improves cognition and reduces oxidative stress in rats with vascular dementia

This study investigated the neuroprotective effects of (2R,3S)-pinobanksin-3-cinnamate (PNC) in rats with occlusion-damaged bilateral common carotid arteries. Administration with PNC (5 and 10 mg/kg/day) for 5 weeks significantly improved the behavioral performance of rats with vascular dementia, as showed in the Morris water maze test by shortening the escape latency and latency of crossing, completing more platform crossings, as well as spending more time in the target zone. Further evaluations found that PNC could markedly decrease malondialdehyde levels, enhance superoxide dismutase activity and glutathione levels, and decrease the release of cytochrome c as well as the activities of caspases. Moreover, PNC increased Nrf2 and anti-apoptotic bcl-2 protein expression, while Nox1 and pro-apopotic bax protein expression was decreased. PNC may exert its neuroprotective effects through counteracting oxidative stress and has the potential to treat vascular dementia.

Ameliorative Effect of a Selective Endothelin ETA Receptor Antagonist in Rat Model of L-Methionine-induced Vascular Dementia

The present study was designed to investigate the efficacy of selective ET_A receptor antagonist, ambrisentan on hyperhomocysteinemia-induced experimental vascular dementia. L-methionine was administered for 8 weeks to induce hyperhomocysteinemia and associated vascular dementia in male rats. Ambrisentan was administered to L-methionine-treated effect rats for 4 weeks (starting from 5^th to 8^th week of L-methionine treatment). On 52^nd day onward, the animals were exposed to the Morris water maze (MWM) for testing their learning and memory abilities. Vascular endothelial function, serum nitrite/nitrate levels, brain thiobarbituric acid reactive species (TBARS), brain reduced glutathione (GSH) levels, and brain acetylcholinesterase (AChE) activity were also measured. L-methionine-treated animals showed significant learning and memory impairment, endothelial dysfunction, decrease in/serum nitrite/nitrate and brain GSH levels along with an increase in brain TBARS levels and AChE activity. Ambrisentan significantly improved hyperhomocysteinemia-induced impairment of learning, memory, endothelial dysfunction, and changes in various biochemical parameters. These effects were comparable to that of donepezil serving as positive control. It is concluded that ambrisentan, a selective ET_A receptor antagonist may be considered as a potential pharmacological agent for the management of hyperhomocysteinemia-induced vascular dementia.

Nimodipine improves regional cerebral blood flow and suppresses inflammatory factors in the hippocampus of rats with vascular dementia

OBJECTIVE

To study the effect of nimodipine on hippocampal regional cerebral blood flow (rCBF) and proinflammatory cytokines in rats with experimental vascular dementia.

METHODS

Male Sprague Dawley rats were randomly divided into four groups (n = 15/group): sham operated controls (group A); focal cerebral ischaemia (group B); vascular dementia (group C); and vascular dementia treated with 20 mg/kg nimodipine daily (group D). The Morris water maze test evaluated learning and memory, and magnetic resonance perfusion-weighted imaging was used to measure rCBF. Hippocampal levels of nuclear factor-κB (NF-κB), tumour necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) were measured.

RESULTS

Compared with group C, rats in group D demonstrated significantly improved learning ability and significantly increased hippocampal rCBF. The levels of NF-κB, TNF-α and IL-1β were significantly lower in group D than in group C. Hippocampal nerve cell morphology was abnormal in group C but near normal in group D.

CONCLUSIONS

Nimodipine improved the symptoms of cognitive impairment, increased rCBF, reduced hippocampal cytokine levels and alleviated neuronal injury in the hippocampus of rats with experimental vascular dementia.