The Neuroprotective Effect And Mechanisim Of Ginsenoside Rg1 On Mice Brain With Cerebral Ischemia

Cerebrovascular disease (CVD)is a dysfunction of brain disease induced by many kinds of abnormity in vascular and blood flow. it is a common and frequently-occurring disease in nervous system, which death rate probably rise to 10% and the third cause of death in all diseases. The later complications of CVD lead to 70%～80% survivors remain some severe symptoms, such as paralysis,dementia,aphasia. The ischemic CVD is a common form of CVD, probably up to 70%～80%. Dementia is a progressive disorder which is accompanied by cognitive decline and behavioural problems, which is one of the most common complication of CVD. Dementia could cause of disability in the aged population. It is reported that the 78% patients of CVD showed obstacle in cognitive in different degrees. The typical changes of pathology in Dementia is that the number of neurons in cerebral cortex and hippocampus displayed decreased significantly. the incidence of CVD shows increase every year, the later pathological changes may probably make the patients dementia which put big burden on family and society, therefore it is important to find methods for preventing and remeding apoptosis of neurons in cerebral cortex and hippocampus. Previous studies have indicated that Mitochondrial dysfunction may be one of crucial factors implicating in degeneration of neurons in Dementia, Mitochondrial is an energy factory in cells, when cell occur ischemia, the chain of electron transmission in Mitochondrial develop obstacle, the road of apoptosis signal priming in cell, at last cell death. Caspase pathway is presumed to be a typical rode to apoptosis, the first actived protein is capase-9, then caspase-3/6/7. So Caspase-9 is a key determiner in neuronal death and neurodegeneration. it is necessary, thus, to investigate novel strategies on preventing neurons from ischemia lesions and improving the treatment of dementia.Ginsenoside Rg1 is one of major important active component of Ginsenoside , in recent years, the neuroprotective effect of Ginsenoside Rg1 has arised researchers concern. It is reported that Ginsenoside Rg1 could inhibit apoptosis of dopamine neurons in substantia nigra in PD. It is necessary to research that whether Ginsenoside Rg1 would perform neuroprotective in cell death in cerebral cortex induced ischemia or not , which would provide some experimental datas for further study in apoptosis in CVD and dementia.Mammalian neurokinins [NKs] are a family of tachykinin peptides that include substance P (SP; neurokinin-1, NK-1), neurokinin A (SK; NK-2; neurokinin A) nd neurokinin B (NK; NK-3; neurokinin B). Their biological functions are mediated by three distinct G-protein coupled neurokinin receptors, namely SP receptor (SPR: NK-1 receptor, NK-1R), neurokinin A receptor (NK-2R) and neurokinin B receptor (NK-3R). Neurokinin peptides and neurokinin receptors are abundantly distributed in the CNS and known to significantly interact with neurons. Previous evidence has suggested that they may be involved in the regulation of physiological and pathological processes in neurons.Aims of the experiment including:(1)To examine the localization and distribution patterns of neuronkinin-4 receptor (NK-4R), a new style of NKs receptor, in neurons of the cerebral cortex of adult C57/BL mice;(2)later we used the NK-4R marked the survival neurons in cerebral cortex, Further studies should be devoted to elucidate whether Ginsenoside Rg1 are involved in protecting degenerative death of neurons in cerebral cortex in CVD;(3)To observe the mechanism in neuroprotection of Ginsenoside Rg1 is whether involved in modulating the active of caspase-9.Methods of the experiment is as follows:Roles of Ginsenoside Rg1 in regulation of activity of neurons in cerebral cortex and possible mechanism interaction with caspase pathway were studied by using animal models induced by ischemia leison, administration of Ginsenoside Rg1, then by using Nissl staining, immunoenzyme histochemistry and double immunofluorescent staining, the distribution patterns of NK-4R in neurons in the layers of cerebral cortex, the localizations of NK-4R and neuronal nuclear specific protein (NeuN ), NK-4R and glial fibrillary acidic protein (GFAP) , the expression of caspase-9 in the neurons of cerebral cortex of adult mice were observed, their distributions were analyzed by semi-quantitative method, double immunofluorescence, laser scanning confocal microscopy .Major results are including: (1) NK-4R-immunoreactivity was found extensively localized in neuronal somata and neurite of cerebral cortex (layerⅡ,Ⅳ,Ⅵ) , and mainy in layerⅢ,Ⅴ.Double-labeling experiments confirmed that 100% NK-4R-immunoreactive neurons co-expressed NeuN, but not GFAP; (2) Roles of Ginsenoside Rg1 in regulating ischemia lesion induced neurons death were applied in animal experiment. Pretreatment with Ginsenoside Rg1 increased cell activity and numbers of NK-4R marked the survival neurons in cerebral cortex; (3) Roles of Ginsenoside Rg1 in regulating ischemia lesion were perfomed by in vivo animal models. Comparison with that of single ischemia lesion group, treatment with Ginsenoside Rg1 increased the number of NK-4R-stained survival neurons and decreased the number of caspase-9 expression, while single ischemia lesion group showed decreased the number NK-4R-stained neurons and increased number of caspase-9 expression in neurons of cerebral cortex.We have concluded: (1) The localization and distribution of NK-4R in the neurons of cerebral cortex of mice suggests that the novel NK-4R may be involved in the modulation of neuronal properties and the process of neuronal pathological changes in the cerebral cortex of mammals; (2) Intervention effects of Ginsenoside Rg1 on ischemia lesion of neurons in cerebral cortex have indicated that Ginsenoside Rg1 may play neuroprotective role in CVD and Dementia; (3) we also infered that the mechanism neuroprotective of Ginsenoside Rg1 were probably involved in inhibition the active of caspase-9.Our experiment showed the distribution of NK-4R in cerebral cortex; Taken together with previous studies, the present results have indicated that Ginsenoside Rg1 may be implicated in degeneration of neurons and pathogenesis of CVD and Dementia. Our datas also suggest that Ginsenoside Rg1 may function as inhibition in the active of caspase-9. However, apoptosis is a complicated process that many factors and pathways take part in, it is needed to study the neuroprotective mechanism of Ginsenoside Rg1 involved in caspase-9 further.