The Study On The Protection Of TEN On Neurons Apoptosis And Hyperphosphorylation Of Tau Protein In Neurons Of AD Rat Induced By Aβ_1-40

Objective:Alzheimer’s disease(AD) is a kind of progressive neurodegenerative disease with pathologic features including senile plaque(SP)、neurofibrillary tangles(NFTs) and neurons loss.The study found that hyperphosphorylation of tau protein is the main component of NFTs.Tau is a microtubule-associated protein, its main physiological function is to promote microtubule assembly and microtubule stabilization. Hyperphosphorylation of tau protein loss its physiological function, and cause microtubule depolymerization, aggregate to form NFTs. And then lead to neurons Regression and loss its function. With the aging of the population intensified, the Incidence of Alzheimer’s disease increased year by year.Therefore to study the pathogenesis of AD and find the therapy has become one of Research focus. We use Aβ1-40inject into hippocampus CA1region of rat and to establish Alzheimer’s disease-like model to study the protection of TEN on the apoptosis of neurons and the Mechanism of action to reduce the level of hyperphosphorylation of tau proteinMethods:Healthy male SD rats were divided randomly into five groups(n=10):sham operation group; Model control group; TEN Low-dose group; TEN Middle-dose group; TEN High-dose group. Inject Aβ1-40into hippocampus CA1region of rat and to establish Alzheimer’s disease-like model. The treatment group were used TEN to perfuse the stomach lasting a month. Observe the toxic effect and injury effect of AP1-40on the rat cerebral neuronal cells and the protection of TEN to it with technology of HE、nisslstaining and electron microscope. Western blot analysis the protein expression of Bax、Bcl-2、Caspase-3、Cyt-c.Immunohistochemistry respectively observe the protein expression of PKA、PP-2A、Total tau、tau(p-Ser396), western blot analysis the protein content of PKA、PP-2A、Total ta、tau(p-Ser396).Results: 1.The protection of TEN to the injury effect of neurons indurced by Aβ1-40Compared with the sham-operated group, the neurons of Model control group arrange loose,cell body of neurons deformed,cell membrance damaged,axons degenerated, synaptic structure injuried, the quantity of synapse decrease,the density and quantity of synapse vesicles decrease, the thickness of synaptic active zone (PSD) were decreased.Compared with the model group, in the treatment group the quantity of neurons were increased, neurons arrange close,the structure of neurons completed,the cell membrance damage remarkably improved. structure of synaptic become complete, the quantity of synaptic were increased, the density and quantity of synapse vesicles increased, the thickness of synaptic active zone (PSD) were increased.2. The effects of TEN on protein expression of Bax、Bcl-2、Caspase-3、Cyt-c of cerebral neuronal cells in AD ratThe results of western blot showed that, compared with the sham-operated group, in the model group the content of Bax、Caspase-3、Cyt-c remarkably increase,and the content of Bcl-2remarkably decrease.In the treatment group, compared with the model group, the content of Bax、Caspase-3、Cyt-c remarkably decrease, and the content of Bcl-2remarkably increased.3. The effects of TEN on protein content of PK、PP-2A、Total tau、tau(p-Ser396) of cerebral neuronal cells in AD ratThe results of immunohistochemistry show that, compared with the sham-operated group, the expression of PKA in model group remarkably increase; the expression of PP-2A in model group remarkably decrease; the expression of total tau、 tau(p-Ser396) in model group remarkably increase. In the treatment group,compared with the model group, the expression of PKA remarkably decrease; the expression of PP-2A remarkably increase; the expression of total tau、tau(p-Ser396) remarkably decrease.The results of western blot as the same as the results of immunohistochemistry, compared with the sham-operated group, the content of PKA in model group remarkably increase; the content of PP-2A in model group remarkably decrease; the content of total tau、tau(p-Ser396) in model group remarkably increase. In the treatment group,compared with the model group, the content of PKA remarkably decrease; the content of PP-2A remarkably increase; the content of total tau、tau(p-Ser396) remarkably decrease.Conclusions:According to the above results, we obtaine the following conclusions:1. Inject Aβ1-40into hippocampus CA1region of rat can cause neurotoxieity and cell injury. TEN can protect neurons from the toxic and cell injury induced by A(31-40.2. TEN can protect neurons and inhibit apoptosis through activating the expression and provent the leakage of Cyt-C to the cytoplasm, thereby inhibiting the activation of caspase3. TEN can decreas the expression of total tau and restore the level of hyperphosphorylation of tau protein through activating the expression PP-2A and decreas the expression of PKA.