Studys On The Improvement Effect Of Sea Cucumber Cerebrosides And Sea Cucumber Phospholipid On Alzheimer’s Disease

Alzheimer’s disease (AD) is a chronic progressive neurodegenerative diseasewhich was commonly occured in the elderly and characterized by irreversibledegradation in memory and cognition. Senile plaques, neurofibrillary tangles andneurons apoptosis are considered the key pathological hallmarks of AD. Thepathogenesis underlying the development of AD is still unclear, and a variety ofhypothesis have formed until now, the oxidative stress hypothesis is paid closeattention increasingly in recent years. As a precious material, sea cucumber has manyactive ingredients, such as polysaccharides, saponins, cerebrosides and phospholipids,while, studies on the effect of neuroprotection and brain function of these materialswere rare reported. In this study, we separated and extracted the main activeingredients from sea cucumber--polysaccharides, saponins, cerebrosides andphospholipid, in vitro model was established to evaluate the protective effect on PC12cells oxidative damage. Accordingly, we further researched the effect ofneuroprotection and brain function of sea cucumber phospholipids via animal models,and analyzed the mechanisms furtherly. The main results are listed below:First, we measured the effect of sea cucumber active ingredients on the PC12cells by MTT method to observe their cytotoxicity. Results showed that sea cucumbercerebrosides (SCC) had no obvious effect on PC12cells growth rate, sea cucumberphospholipid (SCP) could promote the growth of PC12cells. Therefore, our studychose SCC and SCP as the research object for the following experiments.The neuroprotection effect and its mechanism of SCC and SCP were conductedin vitro using two kinds of oxidative damage models, which were established using hydrogen peroxide (H2O2) and tert-butyl hydrogen peroxide (t-BHP) induced PC12cells oxidative damage, respectively. The results showed that H2O2and t-BHP madePC12cells in a remarkable damage state, SCC and SCP could increase the survivalrate of PC12cells, and cellular morphology recovered compared with the damagegroup, suggested that SCC and SCP had the protective effect on PC12cells oxidativedamage. The mechanism results demonstrated that SCC and SCP reduced intracellularLDH leakage, protecting the integrity of cell membrane; increased the activities ofT-AOC and SOD, improving the antioxidant capacity; down-regulated Bax,Caspase-9and Caspase-3genes expressions and up-regulated the expression of Bcl-2,inhibiting cell apoptosis. These results revealed that the mechanism of SCC and SCPon PC12cells oxidative damage may be depended on these antioxidant andantiapoptosis activities.On the basis of cell experiment, we used the accelerated-senescence prone miceSAMP8and scopolamine induce dementia mice as the animal model to furtherinvestigated the effect of SCP on Alzheimer’s disease measured by open-field test,Barnes maze and Morris water maze. In this study, SAMP8mice showed anxietyphenomenon, and the improvement of SCP on this was not obvious; both SAMP8mice and scopolamine induce dementia mice displayed learning and memory deficitsignificantly. In Barnes maze test, the escape latency of SCP group was shorter thanSAMP8mice, and the error time was also reduced; in Morris water test, SCP couldlargely decreased the latency to find the hidden platform, increased the crossingplatform numbers, extended the residence time in the target quadrant, significantly.These results suggested that SCP could improve the learning and memory deficits ofdementia mice.Combining the results in animal experiments and cell experiments, we measuredoxidative stress indicators in SAMP8mice’s brain, liver tissue and serum to furtherresearch the mechanism of SCP on the brain function. Results indicated that SAMP8mice’s brain tissue showed severe oxidative stress, the damage degree of brain was stronger than liver and serum; SCP treatment mostly dropped MDA,8-OHdG,8-oxo-G and NO content, enhanced the SOD activity and inhibited the NOS activitymarkedly. In view of the results, SCP could inhibit the peroxidation of lipids, DNAand RNA, regulate the oxidative stress balance, decline the cytotoxicity of NO anddecrease cell apoptosis to improve the learning and memory deficits, which was alsoconsistent with the cell experiments in vitro.In conclusion, this is the first time to study the neuroprotective effect of seacucumber active ingredients systematically. We found that SCC and SCP have theprotective effect on PC12cells oxidative damage, and SCP could improve the learningand memory deficits of AD model mice. We also clarified the related mechanism ofSCP in vitro and vivo. This study provided scientific basis for the sea cucumber activeingredients in the therapy and prevention of Alzheimer’s disease, and offered thetheoretical support on high-value utilization of sea cucumber.