Effects of β3 integrin on adhesion and migration of vascular smooth muscle cells induced by growth factor

AIM: To investigate the effect of platelet-derived growth factor (PDGF) on β₃ integrin gene expression and the role of β₃ integrin on adhesion, migration and proliferation of vascular smooth muscle cells (VSMC) induced by PDGF. METHODS: β₃ integxin gene expression was detected by RT-PCr. After β₃ integrin extracellular do-main was blocks, VSMC adhesio, migration and proliferation were measured by adhesion assay awound-culture model an [³H]-TSR incorporation respectively.RESULTS: After the interaction between β₃ integrin and extracellular matrix was blocked, VSMC proliferation was inhibited in some degree and the rate of [³H]-TdR incorporation into VSMC decreased 39%. The cell adhesion and migration were significantly inhibited when 10 mg/L anti-β₃ integrin antibody was added (P＜0.05). When VSMC were treated by PDGF for 6 hours, the expression of β₃ integrin gene was 87% higher than that of control. CONCLUSION: PDGF significantly induces expression of β₃ integrin gene in VSMC, and the interaction between β₃ integrin and ECM protein may play an important role in VSMC adhesion and migration.     

Mouse early integral embryo induces expression of endometrial integrin β3 and leukaemia-inhibitory factor,and improves uterine receptivity in mice

AIM: To investigate the changes of endometrial receptivity under the effect of mouse embryo both in vitro and in vivo, and to figure out which part of the embryo induces the change. METHODS: Scanning electron microscope was applied to observe the pinpode formation on day 4 endometrium both in vitro and in vivo. The expression of integrin β₃ and leukaemia-inhibitory factor(LIF) on day 2 pregnant mouse endometrium , day 4 endometrium after co-culture for 2 d with day 2 embryo , blastomere and zona pellucida as well as control group in vitro were detected by the methods of fluorescent quantitative PCR, immunohistochemistry and Western blotting. The same tests were conducted in the in vivo part of the experiment with the integral embryo or different parts of the embryo being transferred to pseudopregnant mouse uterus. On day 4 of the pregnancy, the endometrium was extracted to carry out the tests. RESULTS: After co-cultured for 2 d with whole embryo, the experssion of integrin β₃ and LIF was higher than that in any other group in the in vitro part. The expression of integrin β₃ and LIF on day 4 of normal pregnancy was higher than that in any other group in the in vivo experiments. CONCLUSION: Mouse embryo as a whole is able to induce better endometrial receptivity, while any separated part of embryo, such as blastomere or zona pellucida, couldn't.     

Cloning of human β thalassemic mutation β IVS II654(C→T) and establishment of its mammalian expression system

AIM: To clone human β-globin gene carrying a thalassemic mutation IVS II654(C→T) and establish a eukaryotic expression system for high-level expression of human β IVS II654 gene in mouse erythroleukaemia(MEL) cells. METHODS: The fragments of human β 654 gene isolated from the β thalassemia patients homozygous for the β 654 mutation were amplified by PCR, and cloned to plasmid pBGT51. Then, the human β LCR and β 654 gene were subcloned from plasmid pBGT51 to the stable mammalian expression vector pcDNA3. 1+ together, and the MEL cells were transfected with this vector using commercially available cationic lipid FuGENE6. The MEL cells were induced for further maturation by DMSO and the expression of human β 654 gene in the MEL cells was identified by RT-PCR. RESULTS: A mammalian expression system of human β thalassemic mutation βIVS II654(C→T) was established. CONCLUSION: The level and the reliability of expression of human β 654 gene in the MEL cells in vitro are similar to that in vivo in human body. This may be a valuable gene therapy model for human β thalassemic mutation βIVS II654(C→T).     

Endoplasmic reticulum stress is involved in cardiomyocyte apoptosis induced by β1-adrenoceptor autoantibody

AIM: To investigate the role of endoplasmic reticulum (ES) stress in cardiomyocyte apoptosis induced by β₁-adrenoceptor autoantibody (β₁-AA). METHODS: The rat model of active immunization with the second extracellular loop of β₁-adrenoceptor was established, and SA-ELISA was applied to detect the level of β₁-AA in serum of actively immunized rats. The apoptosis of cardiomyocytes was detected by TUNEL staining, and the protein expression levels of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP) and caspase-12 in rat heart tissues were determined by Western blot and immunohistochemistry. After purified β₁-AA obtained by affinity chromatography was used to treat H9c2 myocardial cells, the cell viability was measured by CCK-8 assay and the apoptosis was analyzed by flow cytometry with Annexin V-FITC/PI double staining. The H9c2 cells were treated with ER stress inhibitor 4-phenoxybutyric acid (4-PBA) before interfered with β₁-AA, and the changes of cell viability and apoptosis were determined by CCK-8 assay and flow cytometry. RESULTS: Compared with vehicle group, the level of β₁-AA in the serum of rats was significantly increased after active immunization for 2 weeks and further rised in 8 weeks, and increased apoptosis was observed in cardiomyocytes after active immunization for 2 weeks, lasting till 8 weeks. Compared with vehicle group, the protein expression of GRP78, CHOP and caspase-12 increased after active immunization for 4 weeks and 8 weeks. Continuous reduction of cell viability and increased apoptosis of H9c2 cells were induced by β₁-AA. ER stress inhibitor 4-PBA pretreatment in H9c2 cells reversed the increased apoptosis and decreased cell viability induced by β₁-AA, indicating that suppression of ER stress effectively reduced cardiomyocyte apoptosis. CONCLUSION: β₁-AA induces increased apoptosis in cardiomyocytes by activating ER stress.     

Curcumin reduces neuroinflammation stimulated by Aβ25-35 in primary rat microglial cells

AIM: To investigate the effects of curcumin (Cur) on the expression of High mobility group box 1 protein (HMGB1), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) in amyloid-β (Aβ)-induced primary rat microglial cells. METHODS: Microglia were derived from the cerebral cortices of postnatal rat brains. The cells were identified by immunocytochemistry using mouse anti rat Iba-1 monoclonal antibody. A cell model using primary rat microglial cells incubated with Aβ_25-35 as an inflammation model of Alzheimer's disease (AD) was set up. The morphological characters of primary rat microglial cells were observed. The concentration of Aβ_25-35 and the treatment concentration of curcumin were selected by CCK-8 assay. Cultured primary rat microglial cells were divided into 5 groups:normal cell group, Aβ_25-35 group, Cur group, Aβ_25-35+Cur group and Aβ_25-35+DMSO group. The expression of HMGB1, NF-κB, and receptor for advanced glycation end products (RAGE) was detected by Western blot. The levels of HMGB1, IL-1β, and TNF-α in the culture supernatant were measured by ELISA. RESULTS: The purity of primary microglias determined by Iba-1 immunofluorescence was more than 95%. The protein levels of HMGB1, RAGE and NF-κB were significantly increased after Aβ_25-35 stimulation. After treatment with Cur, the protein levels of HMGB1, RAGE and NF-κB were significantly decreased (P<0.05). The levels of HMGB1, IL-1β and TNF-α in the supernatant were significantly increased after Aβ_25-35 stimulation. Cur significantly decreased the level of HMGB1, IL-1β and TNF-α in the supernatant. CONCLUSION: Curcumin significantly inhibits neuroinflammation stimulated by Aβ_25-35 in primary rat microglial cells.     

Effect of Akt/GSK-3β/Snail signaling pathway on EMT in A549/DDP cells mediated by TGF-β1

AIM: To observe the expression of Akt/GSK-3β/Snail signaling pathway-related molecules in cisplatin-resistant cell line A549/DDP mediated by transforming growth factor-β₁ (TGF-β₁), and to explore the association of Akt/GSK-3β/Snail signaling pathway with epithelial-mesenchymal transition (EMT). METHODS: The A549/DDP cells were divided into TGF-β₁ (+) group, TGF-β₁ (-) group and LY294002 group. The morphological changes of A549/DDP cells treated with TGF-β₁ were observed under microscope. The protein expression of E-cadherin and N-cadherin was determined by the methods of immumofluorescence and Western blot. The protein levels of Akt, p-Akt, GSK-3β, p-GSK-3β^Ser9 and Snail were also detected by Western blot. RESULTS: The A549/DDP cells in TGF-β₁ (+) group were dispersive, showed a spindle-like shape and developed pseudopodia. This transformation was conformed to classic EMT markers. Compared with TGF-β₁ (-) group, the protein expression of E-cadherin in TGF-β₁ (+) group was significantly decreased (P<0.05), and N-cadherin was significantly increased (P<0.05). The protein levels of p-Akt, p-GSK-3β^Ser9 and Snail were also significantly increased (P<0.05). Compared with TGF-β₁ (+) group, the protein levels of p-Akt, p-GSK-3β^Ser9 and Snail were significantly decreased in LY294002 group (P<0.05). No difference of Akt and GSK-3β expression between TGF-β₁ (-) group and TGF-β₁ (+) group was observed. CONCLUSION: The mechanism of EMT in A549/DDP cells might be related to Akt/GSK-3β/Snail signaling pathway activated by TGF-β₁.     

Transforming growth factor-β1 regulates hypoxia-induced bronchial epithelial-mesenchymal transition by activation of lysys oxidase

AIM: To investigate whether transforming growth factor-β₁ (TGF-β₁) participates in hypoxia-induced bronchial epithelial-mesenchymal transition (EMT) through lysyl oxidase (LOX). METHODS: Sprague-Dawley (SD) rats were exposed to hypoxia to establish the animal model and were treated with LOX inhibitor β-aminopropionitrile (β-APN). Furthermore, primary rat bronchial epithelial cells were cultured in vitro and exposed either to normoxia or to hypoxia. TGF-β₁, TGF-β₁ receptor inhibitor (SB431542) or β-APN was used in the cell experiments. The content of collagen was measured by colorimetric method. The expression of TGF-β₁, LOX, and 2 EMT-related proteins (namely, the epithelial marker E-cadherin and the mesenchymal marker vimentin) were determined by immunohistochemistry and We-stern blot, respectively. RESULTS: The expression of TGF-β₁, vimentin and LOX and cross-linking of collagen were enhanced in hypoxia-exposed rat and in hypoxia-exposed bronchial epithelial cells, but the enhancement was impaired by the treatment with β-APN. In contrast, the expression of E-cadherin was reduced in hypoxia-exposed rat, and was reversed by treatment with β-APN. In vitro experiments demonstrated that TGF-β₁ and hypoxia led to the morphological phenotype characteristic of EMT in rat bronchial epithelial cells, in which the morphology of rat bronchial epithelial cells was switched from cobble-stone shape in normoxia-exposed group to spindle fibroblast-like morphology in hypoxia-or TGF-β₁-exposed group (P<0.01). Additionally, both β-APN and SB431542 partially prevented TGF-β₁ and hypoxia induced EMT in rat bronchial epithelial cells. TGF-β₁was able to dose-dependently up-regulate LOX expression in rat bronchial epithelial cells, which was blocked by concurrent incubation with SB431542. The up-regulation of TGF-β₁, vimentin, LOX and cross-linking of collagen and down-regulation of E-cadherin in hypoxia-exposed rat bronchial epithelial cells was significantly reversed by incubation with SB431542. CONCLUSION: TGF-β₁ regulates hypoxia-induced EMT in bronchial epithelial cells via activation of the LOX.     

Effects of bortezomib on Treg cells in multiple myeloma and its relationship with tumor burden and chemoresponse

AIM: To investigate the changes of regulatory T (Treg) cells in peripheral blood from multiple myeloma (MM) patients with bortezomib-based treatment, and to analyze the effects of bortezomib on Treg cells in MM and the relationship with tumor burden and chemoresponse. METHODS: Treg cells from 30 newly-diagnosed MM patients were detected by flow cytometry before and after bortezomib-based treatment. Meanwhile, 12 cases with conventional treatment were enrolled as controls. The correlation of Treg cell count with the levels of M protein and serum β₂-microglobulin (β₂-MG) was then statistically analyzed. RESULTS: The patients in early disease stage had lower Treg cell count. Decreased Treg cell count was found in 31 cases with chemoresponse (P<0.01), which did not exist in the 11 cases without chemoresponse. The patients achieved >50% serum β₂-MG reduction showed more obvious changes of Treg cell count than those achieved ≤50% serum β₂-MG reduction (P<0.05). The patients with bortezomib-based treatment showed more apparent decline in Treg cell count than the patients with conventional treatment, which were related to chemoresponse and serum β₂-MG reduction (P<0.05). CONCLUSION: Treg cell count is a reliable index of tumor budern. Both bortezomib-related treatment and conventional treatment can reduce Treg cell count, but the reduction is more obvious in bortezomib-related treatment. Such reduction is related to chemoresponse and tumor burden, suggesting the mechanism of bortezomib curing MM may be by the way of Treg suppression.     

Role of α1 adrenoceptor in proliferation of hypoxic pulmonary artery smooth muscle cells

AIM: To investigate the role of α₁ and β₂ adrenoceptors(α₁AR and β₂AR) in the proliferation of hypoxic pulmonary artery smooth muscle cells (PASMCs).METHODS: PASMCs were isolated by an explant method from neonatal bovine pulmonary arteries. The cultured PASMCs were exposed to 6.6% O₂ for 6 h, 12 h and 24 h. The method of -TdR incorporation was used to measure the proliferation of PASMCs. _i was assayed with Fura-2/AM. The mRNA expression of α₁AR, β₂AR, c-fos and c-myc was determined by Northern blotting. The effects of activation of α₁AR and β₂AR, and inhibition of α₁AR on the above indexes were observed by treating PASMCs with different AR agonists and antagonists under hypoxic condition.RESULTS: Significant increase in TdR incorporation in hypoxic PASMCs with α₁AR activation was observed, and marked decrease in that was induced by α₁AR inhibition. However, no significant change was found after β₂AR activation. _i , the mRNA expression of c-fos, c-myc, α₁AR and β₂AR in PASMCs were increased after hypoxia.CONCLUSION: Hypoxia induces the increase in _i and mRNA expression of c-fos and c-myc, leading to the proliferation of PASMCs. The hypoxic proliferation of PASMCs is intervened by α₁AR, but not β₂AR. The remodeling of pulmonary arteriole and pulmonary hypertension may be involved in the processes of pulmonary arteriole constriction and proliferation induced by hypoxia through up-regulation of α₁AR.     

Effects of different β-adrenergic receptors on cardiac systolic and diastolic functions in hypoxic stress rats

AIM:To explore the effects of different β-adrenergic receptors (β-AR) on the left and right ventricular systolic and diastolic functions in rats under acute hypoxic stress. METHODS:The healthy male SD rats were randomly divided into 4 groups (n=7):control group, non-selected β-AR blocker propranolol group, selected β₁-AR blocker atenolol group and selected β₂-AR blocker ICI 118,551 group, and then the rats were exposed to normoxia (20.9% O₂, 79.1% N₂) and hypoxia (15.0% O₂, 85.0% N₂) condition respectively at the altitude of 2 260 m (Xining, China). The heart rate (HR), the left ventricular systolic pressure (LVSP), the right ventricular systolic pressure (RVSP), and the maximum raise/decline rate of left and right ventricular pressure (±dp/dt_max) were monitored, and the arterial blood gas in normoxia and hypoxia condition were compared to explore the effect of β-AR on the left and right ventricular systolic and diastolic functions in acute hypoxic stress rats. RESULTS:Under normoxia condition, the LVSP, ±dp/dt_max of left ventricular were decreased in propranolol group, atenolol group and ICI 118,551 group, the RVSP and ±dp/dt_max of right ventricle were decreased in propranolol group and atenolol group (P<0.05). Under hypoxia condition, the PaO₂, LVSP, ±dp/dt_max of left ventricle were decreased in all groups compared with the normoxia group, and the ±dp/dt_max of right ventricle was increased in all groups (P<0.05), also the degree of index change in control group was more obvious than that in propranolol group and atenolol group. CONCLUSION:The activation of β₁-AR is an important compensatory regulation for heart function during hypoxic stress. However, the compensatory enhancement of right heart function under acute hypoxia condition which through tonogenic dilation is more significant for maintaining the normal circulating blood flow.     

Phasic change of water soluble major crystallins with aging in rats

AIM: To study the correlation between phasic change of the relative quantity of major crystallins with aging in rats. METHODS: Six groups of SD rats (age 1 d， 8 d，2 weeks，8 weeks，8 months and 1.5 years) were raised routinely. Water soluble crystallins were extracted and separated by two－dimensional polyacrylamide gelelectrophoresis. After comassize blue staining，the crystallins patterns were scanned and analyzed. RESULTS: (1) Out of the eighteen water soluble major rat crystallins tested in each group, seven showed gradual phasic changes in relative quantity of crystallins, but there were no significant changes in total quantity of water soluble crystallins. (2) Phasic changes in these crystallins presented four different patterns: increasing (βB₄、αB₂、αA₂、βA₁), decreasing (β₇、β₈、γ_2,3、γ_5,6),relatively stable(βA₃、βB₅), and irregular. (3) The ratio of βB₄ /αA₂ increased gradually with the rat aging process. CONCLUSION: The gradual phasic changes in relative quantity of crystallins reflect the aging status of rat crystalline.     

Changes in serum TGF β1 in type 2 diabetic patients

AIM: To explore the changes in serum TGF β₁ in type 2 diabetes mellitus. METHODS: Forty-five cases type 2 diabetes mellitus patients were divided into three groups according to urine albumim excretion rate(UAER): normoalbuminuria(NA)group and microalbuminuria(MA) group and macroalbuminuria group (Overt DN). Serum TGF β₁, fasting blood glucose(FBG), HbA_1c,BUN,Cr,Ccr,lipidemia were detected in all cases. RESULTS: Serum TGF β₁ in NA, MA and ODN groups was higher than that in control. Serum TGF β₁ was positive correlation with Cr(r=0.390,P＜0.05), LDL(r=0.503,P＜0.01), HbA_1c (r=0.676,P＜0.01), and UARE(r=0.777,P＜0.01). CONCLUSION: Type 2 diabetes mellitus have a higher serum TGF β₁ than controls, serum TGF β₁ was positive correlation with HbA_1c and injury of renal function.     

Inhibitory β-adrenergic receptor in heart

β₃-adrenergic receptor is the third subtype of β-adrenergic receptors. The genetic structure and pharmacological property of β₃-adrenergic receptor are markedly distinguished from β₁-and β₂-adrenergic receptor subtypes. Recently studies show that myocardial β₃-adrenergic receptor mediates negative inotropic effect through Gi-protein/NO/cGMP pathway, the expression of β₃-adrenergic receptor and negative inotropic effect mediated by β₃-adrenergic receptor are increased in heart failure. However, because of the low expression of β₃-adrenergic receptor in the heart, the actual pathophysiological significance of β₃-adrenergic receptor remains unknown.     

Antagonistic effect of thalidomide on TGF-β1-induced change of CTGF gene promoter-binding proteins in HELF cells

AIM:To investigate the antagonistic effect of thalidomide (THD) on the activation of connective tissue growth factor (CTGF) gene promoter induced by transforming growth factor-β₁ (TGF-β₁) in human embryonic lung fibroblasts (HELF). METHODS:Luciferase reporter vector driven by CTGF gene promoter was used to detect the effects of TGF-β₁ and THD on the activity of CTGF gene promoter, and DNA pull-down assay with CTGF gene promoter as a probe was used to analyze the changes of CTGF promoter-binding proteins under different conditions. RESULTS:TGF-β₁ increased the activity of reporter driven by CTGF gene promoter (P<0.01), while THD significantly inhibited TGF-β₁-induced increase in the reporter activity dose-dependently (P<0.01). At the same time, THD had inhibitory effect on the TGF-β₁-induced change of CTGF gene promoter-binding proteins (P<0.05). CONCLUSION:Regulation of CTGF gene promoter-binding proteins takes part in TGF-β₁-induced activation of CTGF gene promoter, while THD has antagonistic effect on this process.     

Effect of lysophosphatidic acid on expression of integrin β6 in epithelial cells

AIM: To investigate the effect of lysophosphatidic acid (LPA) on the expression of integrin β₆ (ITGB6) for determining the role of transforming growth factor β (TGF-β) activation induced by LPA in this process. METHODS: Normal human bronchial epithelial (NHBE) cells were primarily cultured in 6 well plate and stimulated with LPA. The mRNA expression of ITGB6 and the level of cell surface ITGB6 protein were detected by RT-PCR and flow cytometry,respectively. The activity of active TGF-β induced by LPA was measured by the method of transformed mink lung epithelial cells (TMLC) transfected with TGF-β responsive plasminogen activator inhibitor 1(PAI-1) promoter fused with firefly luciferase reporter gene. RESULTS: After stimulated with LPA at concentration of 10 μmol/L for 2 h, the mRNA expression of ITGB6 in epithelial cells was significantly increased in a time-dependent manner. The results of flow cytometry showed that the protein level of ITGB6 on cell surface was obviously increased after treated with LPA at concentration of 10 μmol/L for 4 h. The active TGF-β induced by LPA in epithelial cells was blocked by an α_Vβ₆ blocking antibody. However, α_Vβ₆ blocking antibody failed to inhibit the mRNA expression of ITGB6 induced by LPA. CONCLUSION: LPA induces the mRNA and cell surface protein of ITGB6 in epithelial cells. The up-regulated ITGB6 expression by LPA is independent on LPA-induced TGF-β activation.     

Effects of lentivirus-mediated transfection of shRNA targeting Adra1d gene on calcium and calmodulin in rat aortic vascular smooth muscle cells

AIM:To investigate the effects of lentivirus-mediated transfection of shRNA targeting α_1D-adrenergic receptor (Adra1d) gene on calcium ion (Ca²⁺) and calmodulin (CaM) in vascular smooth muscle cells (VSMCs) of rat aorta. METHODS:Single oligonucleotide sequences of shRNA targeting rat Adra1d gene were design and synthesized, and then the shRNA was constructed and cloned into GV248 vector. The U6-shRNA carrier and expression vector were transfected into 293T cells together and packed with lentivirus, and the supernatant was collected and concentrated by overspeed centrifugation. The VSMCs of rat aorta were transfected with recombinant lentivirus vector. The interference effects were identified by RT-qPCR and Western blot. The concentration of Ca²⁺ in VSMCs was detected by laser confocal inspection, and the expression of CaM at mRNA and protein levels in the VSMCs was determined by RT-qPCR and Western blot. RESULTS:The lentiviral shRNA expression vector was successfully constructed. The titer of the concentrated virus was 3×10¹¹ TU/L. The mRNA and protein expression levels of Adra1d in the rat aortic VSMCs were significantly reduced after transfection. The interference efficiency of Lv-shRNA4-Adr to Adrald gene was greater than 85%. After target silencing of Adra1d gene, compared with scrambled group, the Ca²⁺ fluorescence intensity of rat aortic VSMCs was significantly increased. Moreover, the mRNA and protein expression levels of CaM were also increased significantly. CONCLUSION:A lentiviral shRNA expression vector targeting rat Adra1d gene was successfully constructed, which significantly increased Ca²⁺ concentration and CaM expression in rat aortic VSMCs.     

Cloning the full-length rat Nor1 cDNA using T4 DNA-ligase-mediated 5'RACE

AIM: To clone the full-length of 75A EST. METHODS: After the extraction of total RNA from primary cultured rat cerebellar granule cell of 7DIV in the medium containing 25 nmol/L KCl,T₄ DNA ligase-me-RESULTS: The first round of 5'RACE produce a 2.5 kb band, and 75A EST was identified to be partial sequence of Neuron-derived orphan receptor (Nor1) gene. After two more rounds RACE, we firstly cloned the full-length of Nor-1 cDNA. diated 5’RACE was used to retrieve 5’unknown sequence of 75A EST, and the first round 5’RACE PCR product was subcloned into pGEM-T easy vector for sequence and homogeneous analysis.CONCLUSION: T₄ DNA ligase mediated 5'RACE is an efficient method to retrieve information about the 5' termini of mRNAs, and lay a foundation for further study which role Nor1 play in the cerebellar granule cell's differentiation or survive.     

Effect of tenuigenin on tau protein phosphorylation at Ser396 site in neurons of AD rats induced by Aβ1-40

AIM:To investigate the effect of tenuigenin(TEN) on hyperphosphorylation of tau protein in neurons of amyloid β-peptide_1-40(Aβ_1-40) -induced Alzheimer disease(AD) rats. METHODS:Aβ_1-40 was injected into hippocampus CA1 region of the rats to establish AD model. TEN at different doses(18.5 mg/kg, 37.0 mg/kg and 74.0 mg/kg) was intragastrically administered. The protein expression of protein kinase A(PKA),protein phosphatase 2A(PP2A), total tau and p-tau(Ser³⁹⁶) in the neurons was observed by the method of immunohistochemistry. The protein content of total tau and p-tau(Ser³⁹⁶), and the expression level of PKA and PP-2A were detected by Western blotting analysis. RESULTS:In Aβ_1-40 group, the level of total tau, the phosphorylation of tau protein and the expression of PKA were significantly increased compared with those in sham operation group. Meanwhile, the expression of PP2A in Aβ_1-40 group was lower than that in sham operation group. In TEN treatment group, the level of total tau, the phosphorylation of tau protein and the expression of PKA were markedly decreased, and the expression of PP2A was increased as compared with Aβ_1-40 group. CONCLUSION:TEN may protect the neurons from the toxic effect of Aβ_1-40 and reduce the hyperphosphorylation of tau(Ser³⁹⁶) in the neurons of AD rats by activating the expression of PP2A and inhibiting the expression of PKA.