Role of Notoginsenoside Rg1 in Improving Spatial Cognitive Ability and Lowering Phosphorylation Level of Tau Protein in AD Model Rats

[Objectives] To study the effects and mechanism of notoginsenoside Rg1 on the spatial learning and memory and phosphorylated tau protein in the AD( Alzheimer's Disease) model rat. [Methods]The AD model rat was replicated by injection of Aβ_(25-35) in the left lateral ventricles of SD rats. The low dose( 25 mg/kg),middle dose( 50 mg/kg) and high dose( 100 mg/kg) notoginsenoside Rg1 was used for intragastric administration,respectively,two times every day. After 4 weeks,the Morris water maze test was done to detect the learning and memory capacity,and the immunoblotting,immunohistochemical methods were used to detect the changes in the phosphorylation level and distribution of tau protein in hippocampus of the rats. [Results] After the intracerebroventricular injection of Aβ_(25-35),the learning and memory capacity of the model rats was significantly lower than the learning and memory capacity of the normal control rats. The immunoblotting test results showed that the phosphorylation level of tau protein threonine 231 site( Thr231) in hippocampus was significantly increased,and the nonphosphorylation level was significantly decreased. The morphological testing results showed that the phosphorylation level of tau protein Thr231 of AD model rats was increased markedly in region of DG,CA1 and CA3 of the hippocampus. The intervention of the middle dose notoginsenoside Rg1 could significantly improve the learning and memory capacity of the model rats in Morris water maze. The notoginsenoside Rg1 in three different doses could all reduce the phosphorylation level of tau protein Thr231 in the hippocampal DG,CA1,CA3 regions,and there were no significant differences among the three doses. [Conclusions]The notoginsenoside Rg1 could improve Aβ_(25-35)-induced spatial learning and memory impairment of the AD model rats,and decreased the phosphorylation level of tau protein in hippocampus.

Tau protein,phosphorylated tau protein,and beta-amyloid 42 levels in patients with neurodegenerative diseases complicated by cognitive deficits A non-randomized,concurrent,case-control investigation

BACKGROUND： The differential diagnosis of many neurodegenerative disorders depends primarily on clinical symptoms together with imaging methods. Recently, increased importance has been placed on the use of biomarkers for diagnosing various neurodegenerative disorders. OBJECTIVE： To assess the feasibility of tau-protein, phosphorylated tau-protein, beta-amyloid 42 （Aβ42）, and 14-3-3 protein as biomarkers for diagnosing several neurodegenerative diseases complicated by cognitive deficits. DESIGN, TIME AND SETTING： A non-randomized, concurrent, case-control investigation was performed in three medical centers in the Czech Republic （Department of Neurology at the University Hospital in Hradec Kralove, Department of Neurology at the 2rd Medical Faculty, and the University Hospital Motol） between October 2000 and November 2006. PARTICIPANTS： Eighteen patients with probable AIzheimer＇s disease, 4 patients with Creutzfeldt-Jakob disease, 10 patients with frontotemporal dementia, 9 patients with clinically isolated syndrome suggestive of multiple sclerosis, and 7 patients with multiple sclerosis, as well as 38 race-, nationality-, and age-matched cognitively intact controls, were included in the study. Diagnoses were established based on the following criteria： the criteria for Alzheimer＇s disease proposed by the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer＇s Disease and Related Disorders Association, WHO criteria for Creutzfeldt-Jakob disease, Neary criteria for frontotemporal dementia, and McDonald＇s criteria for multiple sclerosis. All included patients were confirmed to suffer from various degrees of dementia. METHODS： Enzyme-linked immunosorbent assay was used to measure concentrations of tau-protein, phosphorylated tau-protein, and Aβ42 in cerebrospinal fluid （CSF） samples collected by standard lumbar puncture from each patient. Moreover, 14-3-3 protein was assessed by Western blot in CSF of Creutzfeldt-Jakob disease patients. Cognitive status was assessed using the Mini Mental Scale Examination （MMSE） in all subjects. MAIN OUTCOME MEASURES： Establishment of biomarkers with greatest specificity and sensitivity for the investigated disorders according to Receiver Operating Characteristic curves, which were based on values from patients and controls; correlation between concentrations of given biomarkers and demographic parameters, diagnosis, duration of disease, and level of cognitive deficit. RESULTS： Increased concentrations of total tau protein and phosphorylated tau protein, and decreased levels of Aβ42, in CSF of Alzheimer＇s disease patients reached the required sensitivity/specificity ratio of 80% or greater. A marked elevation in CSF concentrations of total tau protein showed even greater sensitivity than 14-3-3 protein in Creutzfeldt-Jakob disease. There was no association between selected biomarkers and frontotemporal dementia or multiple sclerosis. Phosphorylated tau-protein was the only biomarker that noticeably correlated with MMSE scores for Alzheimer＇s disease.CONCLUSION： Levels of total tau protein, phosphorylated tau protein, and A!342 in the CSF could differentiate patients with Alzheimer＇s disease and Creutzfeldt-Jakob disease from healthy controls and patients with other neurodegenerative disorders. The diversity of absolute values demonstrates the necessity to establish a specific standard for each laboratory.

Cellular and molecular mechanisms underlying the action of ginsenoside Rg1 against Alzheimer’s disease

Ginsenoside Rgl inhibits oxidation, aging and ce this study, we pretreated rat brain tissue sections I apoptosis, and improves cognitive function. In with ginsenoside Rgl, and established brain slice models of Alzheimer＇s disease induced by okadaic acid. The results revealed that ginsenoside Rgl pretreatment suppressed the increase in phosphorylated Tau protein expression induced by incubation with okadaic acid, and reduced brain-derived neurotrophic factor expression. These results suggest that ginsenoside Rgl upregulates brain-derived neurotrophic factor expression and inhibits Tau protein phosphorylation in brain slices from a rat model of Alzheimer＇s disease.

Cerebrospinal fluid amyloid beta and tau proteins in atypical Parkinsonism: a review

Progressive supranuclear palsy,corticobasal degeneration,multiple system atrophy and dementia with Lewy bodies are the most common causes of atypical Parkinsonism and enter the differential diagnosis of Parkinson's disease.multiple system atrophy,dementia with Lewy bodies and Parkinson's disease are synucleinopathies,whereas progressive supranuclear palsy and corticobasal degeneration are tauopathies.Multiple cerebrospinal fluid markers have been applied on cohorts of patients with Parkinsonism,with the aim to develop biomarkers for these disorders.Total tau(τΤ),phosphorylated tau at threonine 181(τP-181)and amyloid-beta with 42 amino acids(Aβ42)are considered classical biomarkers for Alzheimer's disease.The aim of the present study is to review the literature regarding these classical cerebrospinal fluid biomarkers in cohorts with Parkinsonism,as well as present data on novel approaches regarding analysis of these proteins.