| Alzheimer disease (AD) is a fatal neurodegenerative disease with primary clinical feature of memory impairment, accompanied by a variety of psychiatric symptoms and behavioral barriers. The pathologic feature of AD are neurofibrillary tangles (NFT) which is in nerve cells and senile plaque (SP) s which is out of nerve cells and mainly at frontal lobe and hippocampus, It's incidence increased year by year with the etiological factors and pathogenesis is unknown, At present, there has no effective therapy method and means, so more deeply studies about AD are required for new drugs or new ideas to cure this disease.Objective:1. In vivo studies the Influence of TEN on learning-memory, cholinergic system and tau protein phosphorylation in AD mice induced by Aβ1-40.2. In vitro studies the Influence of TEN on apoptosis, tau phosphorylation and neurotransmitter related proteins in PC 12 cell model induced by Aβ1-40.Method:1. In vivo, the AD mouse model was established by injection of pre-aggregated Aβ1-40 into the unilateral hippocampus, next the AD mice were given TEN by gavage 30 days. Then pathological change were examined through HE staining; Learning and memory ability were determined by Morris water maze; Activity of AchE were measured by biochemical methods in the different groups of mice brain tissues; The expression of ChAT, tau, PKA and PP2A were assessed by immunohistochemistry.2. In vitro, PC12 cell model was made by Aβ1-40 and then co-cultured intervention with TEN.Then cell viability of each group were test by MTT; The apoptosis rate of each group was detected with FCM; Pathological change were examined through HE staining in each group; The expression of apoptosis related proteins (Bax, Bcl-2, Cyt-C),tau protein phosphorylation-related protein (Tubulin, tau, PKA, PP2A) and neurotransmitter-related proteins (ChAT, synaptophysin, M1 receptor) were assessed by immunohistochemistry.Results:1. In vivo, compared with the model group, the average escape latency were obviously shortened, the crossing times increased significantly in the Morris water maze, nerve cells obvious increased in the cortex and hippocampus, the activity of AchE decreased and the expression of ChAT were increased in the middle and high dose groups, and those differences were statistically significant (P<0.01, P<0.05), while the low dose group were no significant difference (P>0.05).2. In vivo,compared with the model group, the expression of tau and PKA were significantly reduced while the expression of PP2A were increased obviously in the treatment groups, and those differences were statistically significant (P<0.01, P<0.05);3. In vitro, compared with the model group, the cell viability was significantly increased; the apoptosis rate was obviously reduced; the ratio of bax/bcl-2 and the expression of Cyt-C were also reduced greatly, and those differences were statistically significant (P<0.01, P<0.05) while the low dose group were only on the increase (P>0.05)4. In vitro, compared with the model group, the expression of tau and PKA were reduced while the expression of tubulin, PP2A, M1, ChAT and Syn were increased obviously, and those differences were statistically significant (P<0.01, P<0.05)Conclusion:1. TEN can reduce nerve cells toxicity of Aβ1-40 by regulating the activity of AchE and ChAT, increasing the content of Ach to improve learning and impaired memory in AD mice.2. TEN can balance the phosphorylation level of tau to ease the neurofibrillary tangles by increasing the expression of PP2A and reduceing the expression of PKA.3. In vitro, TEN can inhibit apoptosis and reduce toxicity of Aβ1-40 to PC12 cells by regulating the expression of Bax, Bcl-2, Cyt-C, etc.4. In vitro, TEN can regulate the expression of PKA and PP2A, reducing tau content and increase the expression of tubulin, indicating that it can ease the hyperphosphorylation of tau protein to protect the cytoskeleton of neurons, and then be able to infer TEN can reduce NTFs to protect material transport function of neuronal in AD.5. In vitro, TEN can increase the density of M1, Syn and ChAT, suggesting that it can improve the impaired cholinergic system neurons by Aβ1-40. |
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