Effect of Buyanghuanwu decoction on the expression of ERK2 and CaMKⅡβ in hippocampus tissue and on ability of learning and memory in vascular dementia rats

AIM: To investigate the effect of Buyanghuanwu decoction, a Chinese medicine, on the ability of learning and memory in the rats with vascular dementia (VD) and on the protein expression of extracellular signal-regulated kinase 2(ERK2) and calcium/calmodulin-dependent protein kinase Ⅱβ(CaMKⅡβ) in hippocampus CA1 area.METHODS: The rats were divided into 4 groups: sham group, VD group, VD+Buyanghuanwu decoction group and VD+nimodipine group. The VD rat model was prepared by Pulsinelli's four-vessel occlusion. At 7th day, 14th day or 28th day after operation, the behaviors of the rats were tested by Morris water maze. The morphological changes of the neurons in hippocampus CA1 area were observed by HE staining 30 d after operation. Western blotting was used to observe the protein expression of ERK2 and CaMKⅡβ in the brain tissues of hippocampal CA1 area of the VD rats. RESULTS: Compared with sham group, the pathological changes such as irregular arrangement, coagulation necrosis and obvious deletion in the neurons of hippocampus CA1 area in VD group appeared significantly. The obstacle of learning and memory ability was observed and the protein expression of ERK2 and CaMKⅡβ in hippocampal CA1 area was significantly decreased (P<0.05). Compared with VD group, the neurons in hippocampal CA1 area of VD+Buyanghuanwu decoction group and VD+nimodipine group were in eumorphism, lined up in order, and the structure was close to that in sham group. The ability of learning and memory also significantly improved (P<0.05). The protein expression of ERK2 and CaMKⅡβ in hippocampal CA1 area significantly increased (P<0.05). CONCLUSION: Buyanghuanwu decoction promotes the protein expression of ERK2 and CaMKⅡβ in hippocampus CA1 area to protect the neurons from injury, builds up the synapses and promotes the ability of learning and memory in VD rats.     

Effects of gypenosides on cell cycle-related protein expression and calcium homeostasis in hippocampal neurons of rats treated with β-amyloid protein fragmant 1-40

AIM：To observe the effects of gypenosides on the expression of cell cycle-related protein and calcium homeostasis in the hippocampal neurons in the animal model of Alzheimer’s disease (AD) induced by Aβ₁-40.METHODS：The animal model of AD was established through injection of Aβ₁-40 into hippocampus in rats.The ability of learning and memory were verified by the performance of Y-shape maze task.With the method of immunohistochemical staining coupled integral absorbance analysis,the expression of cell cycle related protein in hippocampus was determined in rats.The contents of cytoplasm Ca2+ were determined using Fura-2/AM-fluorescence method.The effects of gypenosides on above indices were studied.RESULTS：Compared with the controls,the learning and memory ability of Aβ₁-40-injected rats were lower,the expression of cyclin A and cyclin B₁ protein in rat hippocampus neurons had hoisted,the contents of calcium in hippocampus were increased significantly.Gypenosides,however,improved all the indexes in varying degrees.CONCLUSION：These results imply that gypenosides improves the learning and memory ability of the rats treated with Aβ₁-40,reverses the expression of cell cycle-related protein and maintains the calcium homeostasis in hippocampus neurons.     

Geniposide attenuates cognitive dysfunction in sleep-deprived rats by inhibiting TLR4/NF-κB signaling pathway

AIM To investigate the effects of geniposide （Gen） on Toll like receptor 4/nuclear factor-κB （TLR4/NF-κB） signaling pathway and cognitive dysfunction in sleep deprived rats. METHODS Wistar rats （n=120） were randomly divided into normal control （NC） group, model （M） group, low-dose （5 g·kg^-1·d^-1） Gen （Gen-L） group, medium-dose （10 g·kg^-1·d^-1） Gen （Gen-M） group, high-dose （20 g·kg^-1·d^-1） Gen （Gen-H） group and Gen-H+LPS （0.4 mg·kg^-1·d^-1, tail vein injection） group. After 7 days of intervention, the sleep deprivation model of rats in M group, Gen-L, Gen-M, Gen-H and Gen-H+LPS group was established by improved small platform water environment. The escape latency of Morris water maze experiment and the behavior correct rate of Y maze experiment were measured. The serum levels of S100B and neuron-specific enolase （NSE）, and the levels of interleukin-1β （IL-1β）, IL-6 and tumor necrosis factor-α （TNF-α） in hippocampus were detected by ELISA. The mRNA levels of TLR4 and NF-κB p65 were detected by RT-qPCR, and the protein levels of TLR4 and NF-κB p65 were determined by Western blot. RESULTS Compared with NC group, the escape latency, the serum levels of S100B and NSE, the hippocampal levels of IL-1β, IL-6 and TNF-α, and the mRNA and protein expression of TLR4 and NF-κB p65 were increased significantly in M group （P<0.01）, and the behavior correct rate was decreased significantly （P<0.01）. Compared with M group, the escape latency, the hippocampal levels of IL-1β, IL-6 and TNF-α, and the expression of TLR4 and NF-κB p65 at mRNA and protein levels were decreased significantly in Gen-L, Gen-M and Gen-H groups （P<0.01）, and the behavior correct rate was increased in turn （P<0.01）. Compared with Gen-H group, the escape latency, the serum levels of S100B and NSE, the hippocampal levels of IL-1β, IL-6 and TNF-α, and the expression of TLR4 and NF-κB p65 at mRNA and protein levels were increased significantly in Gen-H+LPS group （P<0.01）, and the behavior correct rate was decreased significantly （P<0.01）. CONCLUSION Geniposide may inhibit the TLR4/NF-κB p65 signaling pathway to effectively improve cognitive function in sleep-deprived rats and reduce hippocampus inflammation.     

Common pathogenesis of type 2 diabetes and Alzheimers disease: a potential mechanism

AIM: Some epidemiologic evidences suggest an association between type 2 diabetes mellitus (T2DM) and Alzheimer disease (AD). The present study was designed to explore the common pathogenesis in these two diseases by comparing the pathological changes in pancreas and hippocampus, the activity of glucogen synthase kinase 3β (GSK-3β) and protein phosphatase 2A (PP2A) in T2DM rats with those in AD rats. METHODS: The SD rats were fed with high glucose, high fat and high protein for 8 weeks, and then injected with streptozocin (STZ) to establish the T2DM models. The model of AD was made by injection of STZ in hippocampus. The levels of hyperphosphorylated tau protein and β-amyloid protein (Aβ) in hippocampus and pancreas were analyzed by Western blotting and immunochemistry. The activities of GSK-3β and PP2A were determined by using γ-32P-ATP and the specific peptide substrate. RESULTS: In hippocampus of T2DM rats, the tau protein was hyperphosphorylated, the Aβ level was raised, the activity of PP2A was increased and the activity of GSK-3β was decreased, which were also observed in the hippocampus of AD rats. In the AD rats, the Aβ level in pancreas was found to rise, the activity of PP2A decreased and the activity of GSK-3β increased, which were similar to the changes in pancreas of T2DM rats. However, tau protein was not detected in the pancreas of both groups. CONCLUSION: These findings suggest that there are some common pathological changes between T2DM and AD. The hyperphosohorylation of tau protein in hippocampus, the raised Aβ level in hippocampus and pancreas, as well as the corresponding activities of PP2A and GSK-3β may contribute to the pathogenesis in the development of T2DM and AD.     

Effect of autophagic inhibitor 3-methyladenine on apoptosis of hippo-campal neurons induced by Aβ(25-35)

AIM: To investigate the influence of autophagy on the apoptosis of hippocampal neurons in the rat model of Alzheimer disease.METHODS: Sprague-Dawley rats were divided into model group, autophagic inhibitior 3-methyladenine (3-MA) pretreatment group and control group.In model group, the rats were anesthetized and placed in a stereotaxic apparatus.Hippocampus CA1 area microinjection was performed and Aβ(25-35) was applied to establish the model of AD.3-MA in 0.9% saline was administered by the same way prior to Aβ(25-35) infusion.The learning and memory ability of the rats was observed by Morris water maze.The ultrastructure of the hippocampal neurons, the formation of autophagic vesicles, beclin-1 expression and cell apoptosis were detected after behavioral experiment.RESULTS: Compared with model group, the learning and memory ability of the rats in 3-MA group significantly impaired (P<0.05) and the apoptotic rate of the hippocampal neurons significantly increased (P<0.05).Moreover, the expression of beclin-1 was declined.In model group, hippocampal neurons showed double membrane wrapped in the autophagic vacuoles, and the neuronal damages were significantly milder than that in 3-MA group.CONCLUSION: Decrease in the levels of neuronal autophagy increases the neuronal apoptosis, indicating that increasing neuronal autophagy may have therapeutic potential for AD.     

Effects of dexmedetomidine on behaviors and expression of BDNF and mTOR in hippocampus of depressive rats

AIM: To investigate the effects of dexmedetomidine (DEX) on the behaviors and the expression of brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) in the hippocampus of depressive rats. METHODS: Sprague-Dawley (SD) rats were randomly divided into 5 groups: sham operation group, model group, and DEX (2.5, 5 and 10 μg/kg) groups. The rats were randomly selected in each group (n=12). The rat depression model was established by chronic unpredictable mild stress and ovariectomy. The rats in DEX groups received daily DEX treatment via intraperitoneal injection for 21 d. The forced swimming immobility time (FSIT) and open-field test were used to evaluate the antidepressant effect of DEX. Escape latency and times of crossing the flat were evaluated by Morris water maze. The histological changes of hippocampal neurons were determined by Nissl staining. The mRNA levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were detected by RT-qPCR. The protein expression of IL-1β, IL-6, TNF-α and BDNF, and the phosphorylation levels of protein kinase A (PKA), cAMP response element-binding protein (CREB), tropomyosin-related kinase B (TrkB), phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and mTOR in hippocampus were evaluated by Western blot. RESULTS: Compared with model group, the FSIT was significantly reduced and the spontaneous activity was markedly increased in DEX groups. The damage of the hippocampal neurons was obviously attenuated, the escape latency was obviously decreased, and times of crossing the flat were markedly increased (P<0.05 or P<0.01). The levels of IL-1β, IL-6 and TNF-α were obviously decreased, and the protein levels of p-PKA, p-CREB, BDNF, p-TrkB and p-PI3K, p-Akt, p-mTOR in hippocampal tissues were obviously increased (P<0.05 or P<0.01). CONCLUSION: Dexmedetomidine improves the behaviors and the spatial learning and memory ability of depressive model rats, which may be related to its anti-inflammatory effects, as well as up-regulating the protein levels of BDNF and p-TrkB, and activating PI3K/Akt/mTOR signaling pathway in the hippocampus.     

Effect of compound of Epimedium, Astragalus and Radix Puerariae on expression of ADAM10 in Aβ-induced hippocampal neuron HT22 cells with or without hepcidin expression knock-down

AIM To explore the effect of compound of Epimedium, Astragalus and Radix Puerariae on the expression of a disintegrin and metalloproteinase 10 （ADAM10） in Aβ-induced hippocampal neuron HT22 cells with or without hepcidin （HAMP） expression knock-down for analyzing the pathogenesis of Alzheimer disease （AD） at cell level. METHODS Hippocampal neuron HT22 cells were cultured in vitro and randomly divided into 7 groups： control group, Aβ group （Aβ_25-35-induced HT22 cells）, RNAi group （HAMP gene was silenced in HT22 cells）, Aβ+RNAi group （HAMP gene expression in Aβ_25-35-induced HT22 cells was silenced）, Aβ+TCM group （Aβ_25-35-induced HT22 cells were treated with Epimedium, Astragalus root and Radix Puerariae effective components）, RNAi+TCM group （HT22 cells with HAMP gene silence were treated with Epimedium, Astragalus root and Radix Puerariae effective components） and Aβ+RNAi+TCM group （Aβ_25-35-induced HT22 cells with HAMP gene silence were treated with Epimedium, Astragalus root and Radix Puerariae effective components）. The silence efficiency of HAMP siRNA was detected by qPCR and Western blot. The ADAM10 expression in each group was determined by immunofluorescence, qPCR and Western blot. RESULTS The HAMP siRNA-3 sequence had the highest interference efficiency. Compared with control group, the expression levels of ADAM10 in Aβ group, RNAi group and Aβ+RNAi group were decreased （P<0.05）. Compared with Aβ group,the expression levels of ADAM10 in Aβ+RNAi group was also decreased （P<0.05）, and the expression levels of ADAM10 in Aβ+TCM group was increased （P<0.05）. Compared with RNAi group, the expression levels of ADAM10 in Aβ+RNAi group was decreased （P<0.05）, while the expression levels of ADAM10 in RNAi+TCM group was increased （P<0.05）. Compared with Aβ+RNAi group, the expression levels of ADAM10 in Aβ+RNAi+TCM group was increased （P<0.05）. CONCLUSION The effective components of Epimedium, Astragalus and Radix Puerariae compound promotes the expression of ADAM10 in Aβ_25-35-induced HT22 cells, which mechanism may be related to the expression of HAMP.     

Effect of curcumin on learning-memory ability and expression of HMGB1 and JNK in rat model of Alzheimer disease

AIM: To evaluate the effect of curcumin on impaired learning-memory ability and the expression of high mobility group box protein 1 (HMGB1) and c-Jun N-terminal kinase (JNK) in a rat model of Alzheimer disease (AD). METHODS: Male Sprague-Dawley rats, weighing 250~270 g, were randomly divided into 4 groups (n=9): blank control group (group A), model group (group B), curcumin treatment group (group C, curcumin injected intraperitoneally at 100 mg·kg-1·d-1 for 6 consecutive days) and solvent control group (group D). The rats of AD model were induced by injection of ibotenic acid into the nucleus basalis of Meynert (NBM) bilaterally. All rats were trained in Morris maze to assess the ability of learning and memory. The expression of HMGB1 and JNK in the hippocampus was detected by the methods of immunohistochemistry and Western blotting. RESULTS: Compared with group A, the average escape latency (AEL) in groups B and D were obviously longer (P<0.05), while AEL in group C in the 5th and 6th days were significantly shorter (P<0.05). The releases of HMGB1 in the CA1 and CA3 areas in groups B and D from the nucleus were abundant. Compared with groups B and D, HMGB1 in hippocampal CA1 and CA3 areas in group C secreted out of the nucleus decreased obviously (P<0.05). No significant difference of the release of HMGB1 between group A and group C was observed (P>0.05). No significant difference in the expression of HMGB1 in the hippocampus among the 4 groups was found (P>0.05). However, compared with groups B and D, the expression of JNK in group C was decreased obviously (P<0.05). CONCLUSION: Curcumin significantly improves the learning and memory ability of AD rats. The probable mechanisms may be related to inhibiting the release of HMGB1 from the nucleus of hippocampal neurons and decreasing the expression of JNK in the hippocampus.     

Protective effect of folate and vitamin B12 on Alzheimer-like pathological changes in brain of aged rats with hyperhomocysteinemia

AIM:To explore the effect of hyperhomocysteinemia on the Alzheimer-like pathological changes in the brain of aged rat. METHODS:The rats were treated with homocysteine(Hcy) by intravenous injection through vena caudalis with or without a simultaneous supplementation of folate and Vitamin B₁₂(FB) in the drinking water for 28 weeks. The distribution and aggregation of tau protein were detected by Bielschowsky silver staining. Western blotting was used to determine the protein levels of tau phosphorylation, glycogen synthase kinase 3β(GSK-3β) and protein phosphatase 2A(PP2A). RESULTS:Treatment with Hcy induced hyperhomocysteinemia in aged rats and resulted in the formation of neurofibrillary tangles in the brain. Supplementation of FB effectively reduced the tangles. Hyperhomocysteinemia also induced Alzheimer-like tau hyperphosphorylation at multiple sites(Ser^199/202and Ser³⁹⁶). Hyperhomocysteinemia activated GSK-3β and inhibited the activity of PP2A. Supplementation of FB alleviated the changes of tau and the activities of GSK-3β and PP2A. CONCLUSION:Supplementation of FB ameliorates the hyperhomocysteinemia-induced Alzheimer-like pathological changes of tau protein possibly through regulating the activity of GSK-3β and PP2A in aged rats.     

Transfection with GSK-3β in vivo induces tau hyperphosphorylation at PHF-1 sites

AIM: To probe into tau hyperphosphorylation at PHF-1 sites induced by glycogen synthase kinase-3β (GSK-3β) in vivo. METHODS: Twenty-one rats were randomly allocated to three groups as follows: GSK-3β transfection group, vector group and control group; 0.1 μg/3 μL GSK-3β-HA plasmid or vector was injected bilaterally into cerebrum of the rats respectively, rats without injection were controls. Western blotting and immunohistochemical staining of cortex were carried out to detect the expression of GSK-3β-HA plasmid and tau phosphorylation using phosphorylation-dependent tau antibody PHF-1. RESULTS: After transfection with GSK-3β-HA for 48 h, GSK-3β-HA was expressed in GSK-3β transfection group; and hyperphosphorylated tau at PHF-1 sites accumulated in neurons in the transfected areas. The hyperphosphorylated tau colocalized largely with GSK-3β expressed by the transfected GSK-3β plasmid. CONCLUSIONS: Transfection with GSK-3β in vivo can induce tau hyperphosphorylation involving the pathogenesis of neurodegenerative disorders. These data further prove that GSK-3β is a key kinase to induce tau hyperphosphorylation and may be a therapeutic target for tauopathy-related neurodegenerative diseases.     

Effect of Herba Taxilli extracts combined with miR-375 on viability and apoptosis of osteoarthritic chondrocytes

AIM To study the effects of extracts of Herba Taxilli (Sangjisheng, SJS) on the viability and apoptosis of osteoarthritic chondrocytes and the underlying mechanism. METHODS Human primary osteoarticular chondrocytes (RPOC) were divided into control group, interleukin-1β (IL-1β) group, IL-1β+low-dose extracts of SJS (SJS-L) group, IL-1β+medium-dose extracts of SJS (SJS-M) group, IL-1β+high-dose extracts of SJS (SJS-H) group, IL-1β+anti-miR-NC group, IL-1β+anti-miR-375 group, IL-1β+SJS-H+miR-NC group, IL-1β+SJS-H+miR-375 group. The cell viability was measured by MTT assay, apoptosis was analyzed by flow cytometry, miR-375 expression was detected by qPCR, and the protein levels of cyclin D1, P21, Bcl-2, Bax and caspase-3 were determined by Western blot. RESULTS Compared with control group, the viability of RPOC at 24 h, 48 h and 72 h and the protein expression levels of cyclin D1 and Bcl-2 were significantly decreased (P<0.05), the protein levels of P21, Bax and caspase-3, the apoptotic rate and the expression level of miR-375 were remarkably increased in IL-1β group(P<0.05). Compared with IL-1β group, the cell viability at 24 h, 48 h and 72 h and the protein expression of cyclin D1 in the RPOC were greatly increased (P<0.05), while the expression of P21 was significantly decreased in IL-1β+SJS-M group and IL-1β+SJS-H group(P<0.05).The apoptotic rate, Bax, caspase-3 protein and miR-375 expression were obviously decreased (P<0.05), and Bcl-2 protein level was significantly increased in IL-1β+SJS-H group compared with IL-1β group(P<0.05). Compared with IL-1β+anti-miR-NC group, the expression of miR-375, the protein levels of P21, Bax, caspase-3 and the apoptotic rate in the RPOC of IL-1β+anti-miR-375 group were markedly decreased (P<0.05), while the cell viability at 24 h, 48 h and 72 h and the protein levels of cyclin D1 and Bcl-2 were significantly increased (P<0.05). Over-expression of miR-375 reversed the effects of extracts of SJS on the viability and apoptosis of RPOC with IL-1β stimulation. CONCLUSION The extracts of Herba Taxilli promotes the viability and inhibits apoptosis of RPOC treated with IL-1β, which is related to the regulation of miR-375 expression.     

Effects of acute and chronic hypobaric hypoxia on spatial learning and memory functions in adult rats

AIM: To explore the effects of acute and chronic hypobaric hypoxia on spatial learning and memory functions in adult rats. METHODS: Three separate experiments were carried out. In the first experiment, 30 adult male SD rats were divided into control group (group A) and acute hypoxia group (group B, 7 000 m, 72 h). Learning and memory functions were tested by Morris water maze. The spatial acquisition was performed 4 trails per day, 3 days to reach asymptotic performance. The platform was removed on the 4th day, using a novel start position during the probe trail. The data of escape latency, time in platform quadrant and times of passing platform were recorded. In the second experiment, 26 adult male SD rats were divided into control group (group C) and chronic hypoxia group (group D, 6 000 m, 35 d). The spatial acquisition was performed 4 trails per day, 5 days to reach asymptotic performance. The platform on the 6th day was removed, using a novel start position during the probe trail. The data of escape latency, time in platform quadrant and times of passing platform were recorded. In the third experiment, after trained with Morris water maze by using the method as the second experiment, 30 adult male SD rats were divided into control group (group E) and acute hypoxia group (group F, 7 000 m, 72 h), and 2 h later, the memory functions were reevaluated. RESULTS: In the first day after acute hypoxia exposure, the escape latency in group B was significantly shorter than that in group A. However, the escape latency in the following days and the and times of passing platform was not significantly different. No difference of the escape latency in the following days and the time of passing platform between group C and D was observed. Memory tests didn’t show any difference between group E and F. CONCLUSION: Either acute or chronic hypobaric hypoxia does not affect the spatial learning and memory functions in adult rats.     

Intervention of gossypol and relationship between cognitive function and expressions of 11β-HSD1 and GR in brain of type 2 diabetic rats

AIM: To study the effect of gossypol on the cognitive function of type 2 diabetic rats, and to explore its mechanism. METHODS: Thirty male Sprague-Dawley rats were divided into three groups randomly: normal group, type 2 diabetic group and gossypol treated group. After fed with high-fat diet for 4 weeks, the later two groups were injected with streptozotocin intraperitoneally to establish type 2 diabetic rat model. The animals in gossypol treated group were given gossypol at dosage of 15 mg/kg once per day for 4 weeks by gavage. Since 5th week, the times of gavages were changed into once per week at the same dosage and lasted to 12th week. Learning and memory abilities of rats were assayed with Morris water maze test. The concentration of blood glucose was measured by biochemical method. The levels of serum corticosterone and insulin were detected by enzyme-linked immunosorbent assay and radioimmunoassay, respectively. The protein expressions of 11β-HSD1 and GR in cerebral cortex and hippocampus were determined by Western blotting. The morphological changes of cerebral cortex and hippocampus were observed under light microscope and transmission electronic microscope, respectively. RESULTS: Compared to normal group, the karyopyknosis, dilation of golgiosome and mitochondria swelling of neuron from cerebral cortex and hippocampus were prominent in diabetic group. The concentrations of blood glucose, serum corticosterone and insulin increased significantly (P<0.01). Protein expression of GR decreased (P<0.05), 11β-HSD1 protein tended to increase. Platform searching score was lower (P<0.01) and escape latency was longer (P<0.01) in diabetic group. After treated with gossypol, the concentrations of blood glucose, serum corticosterone and insulin declined (P<0.01). The protein expression of 11β-HSD1 was decreased (P<0.05) and GR was increased (P<0.05). Escape latency was shorter (P<0.01) and platform searching score was increased (P<0.01). CONCLUSION: Gossypol may improve the cognitive function of type 2 diabetic rats. Decreasing the level of 11β-HSD1 and increasing GR protein in the brain may be involved in the mechanism.     

Glyburide reduces PFOS-induced lung injury in young rats through inhibiting NLRP3 inflammasome

AIM: To explore the possible mechanism of NLR family Pyrin domain-containing protein 3 (NLRP3) inflammasome involved in perfluorooctane sulfonate (PFOS)-induced lung injury in young rats. METHODS: Twenty-eight SD rats (21-day-old) were randomly divided into control (C) group, PFOS (P) group, glyburide (G) group and glyburide + PFOS (GP) group. PFOS exposure model and glyburide protection model were established. The lung specimens were collected for HE staining. The levels of myeloperoxidase (MPO) in the lung tissues, interleukin-1β (IL-1β) and interleukin-18 (IL-18) in the bronchoalveolar lavage fluid (BALF) were measured by ELISA. The concentration of PFOS in serum was measured by high-performance liquid chromatography (HPLC). The protein expression of NLRP3, caspase-1 and apoptosis-associated speck-like protein containing CARD (ASC) in the lung tissues was determined by Wes-tern blot. RESULTS: HE staining of lung tissues showed that compared with the control rats, there were obvious inflammatory infiltration in trachea and alveolar interstitium of the rats in P group. Glyburide reduced the inflammatory responses significantly. ELISA results showed that the level of MPO in the lung tissues of the rats in P group was higher than those in other 3 groups (P<0.05). The levels of IL-1β and IL-18 in the BALF of the rats in P group were significantly higher than those in control group and GP group (P<0.05). The results of Western blot showed that the protein levels of NLRP3, caspase-1 and ASC in P group were significantly higher than those in control group and GP group (P<0.01). Immunohistochemical staining results showed that compared with the other 3 groups, the expression of NLRP3 in P group was significantly increased (P<0.01). CONCLUSION: PFOS exposure may lead to lung injury in rats by activating NLRP3 inflammasome and then triggering inflammation, releasing inflammatory factors such as IL-1β. Glyburide specifically inhibits the assembly of NLRP3 inflammasome, suppresses the inflammatory responses and reduces the toxicity of PFOS in lung.     

rAAV-mediated VLDLR gene transfection reduces tau hyperphosphorylation in hippocampus of type 2 diabetic rats

AIM: Abnormal hyperphosphorylation of tau plays a critical role in the pathogenesis of Alzheimers disease(AD), and tau protein was hyperphosphorylated in type 2 diabetes. The present study was designed to explore the phosphorylation level of tau in hippocampus of type 2 diabetes rats which interrupted by very low density lipoprotein receptor(VLDLR)gene transfection. METHODS: Wistar male rats were randomized into 3 groups. The control group(CTL)was fed with normal food. The T2DM group and T2DM mediated VLDLR gene group were on high sugar, high fat and high protein diet for 3 months. The plasma insulin level was measured by RIA method, and the plasma glucose was determined by glucose-oxidase method. Total tau level, the phosphorylation level of tau at individual phosphorylation sites and the level of VLDLR were analyzed by Western blotting. The activity of glycogen synthase kinase 3β, a key component of insulin signal transduction pathway and a known tau kinase, in the hippocampus of rats was determined by using ［γ-32P］-ATP and the specific peptide substrate. RESULTS: No significant difference of total tau level in hippocampus between T2DM group and T2DM mediated VLDLR gene group was observed. Tau protein in T2DM group was found to be more hyperphosphorylated at several AD-related phosphorylation sites(Ser214, Thr217, Ser396, Ser422 and Ser199/202)than that in CTL, while the immunoreaction at tau-1 site is weaker than that in CTL. VLDLR gene therapy reduced hyperphosphorylation sites of Thr217, Ser396, Ser422 and Ser199/202 of tau to almost the control level, but did not change the phosphorylation of Ser214 or Ser422 on tau. The expression of Ser214 was also observed by immunohistochemical assay. The phosphorylated tau modestly increased in hippocampus in T2DM group compared to CTL, but VLDLR gene treatment did not change the phosphorylation level. The phosphorylation of GSK-3β was decreased dramatically in the hippocampus in T2DM rats, and this phosphorylation was significantly increased after VLDLR gene treatment. CONCLUSION: These findings suggest that Raav mediated VLDLR gene treatment partially reverses tau hyperphosphorylation at several sites in T2DM rat hippocampus, which may mediate by inhibition of GSK-3β activity.     

The effect of buyanghuanwu decoction on expression of AMPA receptor GluR1 subunit in mRNA and protein levels in rat hippocampus with vascular dementia

AIM: To observe the effect of buyanghuanwu decoction, a Chinese medicine, on the expression of AMPA receptor GluR1 subunit in mRNA and protein levels in rat hippocampus with vascular dementia (VD). METHODS: One hundred and forty-four rats were randomly divided into 4 groups: sham-operation group, VD model group, nimodipine group and buyanghuanwu decoction treatment group. The rat model of VD was built up by the method of 4 vessel occlusion. The VD rats were intragastrically treated with buyanghuanwu decoction suspension (pharmacognostic 50 g·kg-1·d-1) and nimodipine suspension (20 mg·kg-1·d-1) for 30 d. The learning and memory abilities were evaluated by Morris water maze testing. The change of GluR1 protein in hippocampal neurons in each group of rats was measured with immunohistochemistry and Western blotting techniques. The expression of GluR1 mRNA in hippocampus was determined by real-time fluorescence quantitative PCR. RESULTS: Compared to sham-operation group, the average escaping latency period (s) of Water maze tests in VD rats prolonged significantly and cross-platform time (numbers/min) shortened distinctly (P<0.05). The VD rats treated with buyanghuanwu decoction significantly improved the above-mentioned learning and memory performances (P<0.05); no significant difference of above-mentioned learning and memory performances among the rats in sham-operation group, nimodipine group and buyanghuanwu decoction treatment group was observed (P>0.05). Compared to the rats in sham-operation group, the mRNA and protein levels of GluR1 were apparently decreased in VD rats (P<0.05). The mRNA and protein levels of GluR1 in the neurons of hippocampus in buyanghuanwu decoction treated VD rats were higher than those in the model animals (P<0.05), and no difference was discovered in the rats among sham operation group, buyanghuanwu decoction treatment group and nimodipine group (P>0.05). CONCLUSION: Buyanghuanwu decoction improves the learning and memory abilities in VD rats. The therapeutic mechanism is associated with lessening the neuron injury on CA1 field in hippocampus and restoring the mRNA and protein expression of GluR1.     

Scutellaria barbata flavonoids inhibits NFT aggregation and regulatory mechanism in rats induced by composited Aβ

AIM: To investigate the effects of Scutellaria barbata flavonoids (SBF) on neurofibrillary tangle (NFT) aggregation, tau protein phosphorylation and the regulated mechanism of glycogen synthase kinase (GSK) 3β and protein phosphatase (PP) 2A in the rats induced by amyloid β protein 25-35 (Aβ_25-35) in combination with AlCl₃ and recombinant human transforming growth factor (RHTGF)-β1(composited Aβ). METHODS: The male SD rats were used to establish the simulated Alzheimer disease (AD) model by intracerebroventricular injection of composited Aβ. The Morris water maze was applied for screening the successful model rats with learning and memory deficits. The successful model rats were daily and orally administrated with SBF at doses of 35, 70 and 140 mg/kg or positive control drug Ginkgo biloba leaves flavonoids (GLF) at 140 mg/kg for 37 d. The silver nitrate staining was used to determine the cortical NFT. The protein levels of total tau, phosphorylated protein of tau at Ser199 and Ser214 sites, GSK3β and PP2A in hippocampus and cortex were determined by Western blot. The mRNA expression of GSK3β and PP2A in the hippocampus and cortex was detected by RT-PCR. RESULTS: Compared with sham group, the cell number of positive NFT with silver nitrate staining in model rat cerebral cortex was significantly increased. The protein levels of phosphorylated tau protein at Ser199 and Ser214 sites, GSK3β in the hippocampus and cerebral cortex in the model rats dramatically elevated, and PP2A was marked decreased as compared with the sham group rats. Meanwhile, the mRNA expression of GSK-3β significantly increased but PP2A was decreased. However, these above abnormalities were differently attenuated by treating with SBF at different doses or GLF at 140 mg/kg for 37 d. CONCLUSION: SBF suppresses the NFT aggregation by inhibition of the regulatory functions of GSK-3β and PP2A, thus reducing the phosphorylation of tau protein.