Lycopene supplementation protects vascular dementia gerbils against the impairment of learning and memory

In this study, we investigated the neuroprotective effects of lycopene (Lyc) on vascular dementia (VaD) gerbils and its related mechanisms of anti-inflammatory, anti-apoptotic and anti-oxidant activity. Gerbils were treated with bilateral common carotid arteries. Animals were divided into 1) Sham, 2) VaD model, and 3) VaD model + Lyc (20 mg/kg) groups. Each group (3) was administered intergalactic Lyc twice a day for 28 days. Morris water mazes were used to evaluate learning and memory ability. Nissl, NeuN, and GFAP staining were used to observe histomorphological changes of neural and glial cells in the hippocampus CA1 region. Western blotting was used to detect hippocampus caspase-3, B-cell lymphoma-2 (Bcl-2), Bcl-2 related x protein (Bax), and interleukin (IL)-1, IL-6 and tumour necrosis factor alpha (TNF-alpha) expression amongst other inflammatory factors. Secreted IL-1, IL-6 and TNF-alpha levels were assessed by ELISA in addition to superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), glutathione (GSH) and malondialdehyde (MDA). We found that Lyc increased the learning and memory ability of gerbils by reducing the latency time in the Morris water maze, and increasing spatial memory. Lyc also reduced pathological changes in the hippocampus caused by VaD, reduced apoptosis, and decreased VaD mediated Bcl-2/Bax expression. The levels of inflammatory factors and oxidative stress were also reduced by Lyc in the VaD models. We therefore conclude that Lyc can improve the learning and memory ability of VaD gerbils, the mechanism of which may be related to reduced oxidative stress and apoptosis in VaD hippocampus neurons.