Expression of synaptophysin in hippocampal CA1 region and prefrontal cortex of PTSD rats

AIM:To investigate the expression of synaptophysin in the CA1 region of hippocampus and prefrontal cortex (PFC) of rats with posttraumatic stress disorder (PTSD), and to explore the mechanism of spatial memory changes in PTSD rats.METHODS:Healthy adult SD rats (n=36) were randomly divided into 2 groups:control group and model group, with 18 rats in each group. The rats in model group was continuously given single prolonged stress (SPS) to construct the PTSD model. Morris water maze (MWM) was used to test the learning and memory ability of the rats in the 2 groups. The protein expression of synaptophysin in the hippocampal CA1 area and PFC was examined by immunohistochemistry, Western blot and immunofluorescence experiments. RESULTS:The latency of the rats in searching for the underwater platform in model group was significantly longer than that in control group from the 2nd day (P<0.01) in the MWM experiment, the target quadrant swimming time was significantly shortened (P<0.01), and the times of crossing the platform were also significantly reduced (P<0.01). The results of immunohistochemistry, Western blot and immunofluorescence experiments showed that the expression of synaptophysin was obviously reduced in the CA1 region of hippocampus and PFC in model group as compared with control group (P<0.05 or P<0.01).CONCLUSION:The reduction of spatial memory ability in PTSD rats may be associated with the decreased expression of synaptophysin in the CA1 region of hippocampus and PFC.     

Effects of EGb761 on synaptophysin expression in hippocampus of vascular dementia rats

AIM: To investigate the effects of Ginkgo biloba extract 761 (Egb761) on synaptophysin (SYN) expression in hippocampus of vascular dementia (VD) rats.METHODS: VD rat models, established by repeatedly cerebral ischemia/reperfusion, were randomly divided into two groups: model group and EGb761 treated group (both n=30), and another 30 condition-matched rats were selected as the sham-operated controls. Spatial learning and memory abilities of rats were assessed by Morris water maze (MWM) task, and SYN expression in hippocampal formation of rats in different groups was detected by immunohistochemical technique and image analysis.RESULTS: The MWM escape latency (EL) in model group was highly longer than that in the sham-operated group (P<0.01), while the EL of EGb761-treated group was significantly shorter than that in model group, but still longer than that in the sham-operated group at 1 m, 2 m and 4 m after VD modeling operation (P<0.05 or P<0.01). Immunohistochemical analysis showed that the SYN immunoreactive expression in hippocampal formation in model group greatly decreased and mean optical density of SYN expression highly increased compared with both sham-operated group and EGb761-treated group at three time points (P<0.01).CONCLUSION: EGb761 can increase the expression of SYN in hippocampus, which may be one of important mechanisms of EGb761 in improving learning and memory dysfunction of VD rats.     

Mechanism of coronary artery constriction induced by 5-HT

AIM:To investigate the possible mechanism of coronary artery contraction induced by 5-hydroxytryptamine (5-HT). METHODS:Isolated coronary artery rings were obtained from male Wistar rats, and the vascular tension meter was used to determine the tension of the coronary artery rings. The effects of inhibitors of different signaling pathway on vascular contraction tension induced by 5-HT were observed. RESULTS:Firstly, we found that 5-HT_2A receptor antagonist sarpogrelate (1 μmol/L) completely eliminated the coronary artery contraction induced by 5-HT. Phospholipase C_β (PLC_β) inhibitor U73122 (10 μmol/L and 50 μmol/L), Rho-related protein kinase inhibitor Y-27632 (3 μmol/L and 10 μmol/L) and protein kinase C δ subunit (PKCδ) inhibitor rottlerin (3 μmol/L and 10 μmol/L) significantly inhibited the contraction of coronary artery ring caused by 5-HT (P<0.05). In addition, compared with the untreated group, vascular contraction tension induced by 5-HT was also decreased significantly by L-type calcium channel (Cav1.2) blocker nifedipine (1 μmol/L), store-operated Ca²⁺ entry (SOCE) inhibitor SKF96365 (10 μmol/L and 30 μmol/L) and 2-aminoethoxydiphenyl borate (2-APB, 50 μmol/L and 100 μmol/L) (P<0.05). At the same time, 5-HT also induced vasoconstriction after treated with nifedipine (1 μmol/L) Kerbs-Henseleit (K-H) liquid without calcium (P<0.05). CONCLUSION:5-HT activates 5-HT_2A receptor induced coronary artery contraction, possibly related to the PKC/Rho kinase signaling pathway and calcium regulation.     

Receptor and signaling mechanisms involved in zacopride-induced potentiation of IK1

AIM: To investigate the receptor and signaling mechanisms involved in the potentiation of inward rectifier K⁺ current (I_K1) induced by zacopride, a potent 5-HT₃ receptor antagonist and 5-HT₄ receptor agonist. METHODS: The whole-cell patch clamp technique was used to record I_K1. 5-HT₄-receptor antagonist RS23597-190, 5-HT₃-receptor agonist m-chlorophenylbiguanide (m-CPBG), PKA inhibitor KT5720, PKC inhibitor GF109203X and PKG inhibitor KT5823 were applied respectively to determine the regulatory mechanism of I_K1. RESULTS: In the presence of RS23597-190 at concentration of 10 μmol/L which inhibited I_K1, zacopride at concentration of 1 μmol/L still increased I_K1 with the mean increment of 32.5% in inward current (at -100 mV, P<0.05). The I_K1 increment induced by zacopride was not inhibited by m-CPBG at concentration of 10 μmol/L (P>0.05). Furthermore, PKA inhibitor KT5720 at concentration of 5 μmol/L reversed the effect of zacopride (P<0.05), while PKC inhibitor GF109203X and PKG inhibitor KT5823 both at concentration of 5 μmol/L didn't influence the effect (P>0.05). CONCLUSION: Zacopride potentiates I_K1 via a PKA-mediated signaling pathway, which is independent on 5-HT₄ and 5-HT₃ receptors.     

Effect of Jieyuwan on dendritic spines in prefrontal cortex and hippocampus in WKY depression-like rats

AIM To observe the changes of dendritic spines in prefrontal cortex and hippocampus of Wistar-Kyoto (WKY) depression-like rats, and to explore the effects of Jieyuwan (JYW) on them. METHODS The male WKY rats were selected as the experimental group, and the same strain of Wistar rats were selected as the control group. Firstly, sucrose preference test, open-field experiment and forced swimming test were used to detect the behavior changes in the rats as their baseline. Then, all WKY rats were randomly divided into model (WKY+NaCl) group, WKY+JYW group and WKY+citalopram group. All WKY rats and Wistar rats (Wistar+NaCl group) were administered intragastrically for 21 d, and the changes of behavior after administration were detected by the same behavioral methods. Golgi staining was used to observe the pathological characteristics of dendritic spines in the prefrontal cortex and hippocampus, and Western blot was used to detect the protein expression level of postsynaptic density protein-95 (PSD-95) in the prefrontal cortex and hippocampus. RESULTS Before administration, WKY rats clearly showed depression-like behavior, the density of dendritic spines in the prefrontal cortex and hippocampus decreased significantly (P<0.01), and the protein expression level of PSD-95 was significantly reduced (P<0.01). After treatment with the drugs, the depression-like behavior of WKY rats was significantly attenuated, the density of dendritic spines in the prefrontal cortex and hippocampus increased (P<0.01), and the protein expression level of PSD-95 also increased (P<0.01). CONCLUSION Jieyuwan significantly attenuates the depression-like behavior of WKY rats, and affects the structural changes of dendritic spines and the expression of PSD-95 protein, which further proves that dendritic spines may be one of the importantearly structural changes in depression.     

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.     

Adenosine A2A receptor antagonist SCH58261 attenuates hypoxic-ischemic brain damage in a fetal rabbit model

AIM: To study the effect of adenosine A_2A receptor antagonist SCH58261 on hypoxic-ischemic brain damage (HIBD) in a mature fetal rabbit model.METHODS: Pregnant New Zealand white rabbits at gestational day 29 were selected and were randomly divided into sham-operated group, hypoxic-ischemic group, SCH58261 0.04 mg/kg group, SCH58261 0.12 mg/kg group and DMSO group. The intrauterine rabbit HIBD model was established. All pregnant rabbits were subjected to cesarean section 24 h after the sham operation or experimental procedure to induce hypoxic-ischemic injury in the fetus. The survival neonatal rabbits were kept in a neonatal incubator at 35℃. The general conditions of the newborn rabbits were recorded. The degree of neurobehavioral damage in the newborn rabbits was estimated by a neurobehavioral scoring protocol. The concentration of SCH58261 in the serum of pregnant rabbits, the serum of neonatal rabbits and the brain tissues of neonatal rabbits was measured by mass spectrometry. The mRNA expression of Bcl-2/Bax and protein levels of p-P38 mitogen-activated protein kinase (MAPK) in the cortex, hippocampus and striatum area in the brain of the neonatal rabbits were determined by real-time PCR and Western blot. RESULTS: SCH58261 was detected in the serum and brain tissues of the newborn rabbits. The SCH58261 concentration was approximately 40 μg/L in the brain tissue of the newborn rabbits. The mRNA expression of Bcl-2 in the cortex, hippocampus and striatum of brain tissues in SCH58261 0.04 mg/kg group and SCH58261 0.12 mg/kg group was higher, and the mRNA expression of Bax was lower than those in HI group (P<0.05). The protein level of p-P38 MAPK in the cortex, hippocampus and striatum of brain tissues was reduced in SCH58261 0.04 mg/kg group and SCH58261 0.12 mg/kg group compared with HI group (P<0.05). The protein level of p-P38 MAPK in SCH58261 0.12 mg/kg group was a little lower than that in SCH58261 0.04 mg/kg group (P<0.05). CONCLUSION: Adenosine A_2A receptor antagonist SCH58261 attenuates hypoxia-ischemia induced neonatal brain injury by blocking adenosine A_2A receptor, subsequently inhibiting p-P38 MAPK phosphorylation to reduce neuronal apoptosis.     

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.     

Therapeutic effect of emodin on constipation induced by loperamide in mice

AIM: To study the therapeutic effect of emodin on loperamide-induced constipation in mice. METHODS: The constipation model of mice was established by lopebutamine treatment, and the effects of emodin on defecation frequency, fecal water content and intestinal transit time of the mice during the observation period were detected. Inflammatory infiltration in colon tissue of the mice was observed by HE staining. Serum nitric oxide (NO) content was detected by commercially available kit. The expression of vasoactive intestinal peptide receptor 1 (VIPR1) and 5-hydroxytryptamine type 4 receptor (5-HT₄ receptor) in mouse colon was determined by immunohistochemistry. The effects of emodin on the expression of transient receptor potential cation channel subfamily V member 1 (TRPV1), glial cell-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), nitric oxide synthase (NOS), c-Kit and their ligand stem cell factor (SCF) were detected by Western blot. RESULTS: Emodin significantly increased the number of defecation and fecal water content in the mice during the observation period, and significantly reduced the intestinal transit time and serum NO level in the mice (P<0.05). The results of HE staining showed that emodin significantly reduced the infiltration of colonic inflammation induced by loperamide. Emodin can significantly reduce the increase in VIPR1 induced by loperamine and increased the expression of 5-HT₄ receptor (P<0.01). Emodin increased the expression levels of GDNF and BDNF, reduced the expression levels of TRPV1 and NOS in the colon tissues of loperamine-induced constipation in mice, and significantly increased the expression of c-Kit and SCF (P<0.05 or P<0.01). CONCLUSION: Emodin promotes the defecation behavior of mice with loperamine-induced constipation by increasing intestinal peristalsis and activating a series of smooth muscle contraction-related factors.     

Intervention of hydrogen on memory damage induced by chronic hypoxia-hypercapnia in rats

AIM: To investigate the effects of hydrogen on the memory damage caused by chronic hypoxia-hypercapnia in rats. METHODS: Twenty-four SD rats trained by eight-arm radial maze test were randomly divided into 3 groups:normal control group (NC), hypoxia-hypercapnia+saline group (MS) and hypoxia-hypercapnia+ hydrogen group (MH). The rats in the latter 2 groups were placed in a closed cabin for 8 h/day,6 days/week and lasted for 4 weeks, in which O₂ was 9％-11％ and CO₂ was 5％-6％. In every time after the animals were out of the cabin, the MS rats were intraperitoneally injected with saline (5 mL/kg) and the MH rats were intraperitoneally injected with hydrogen solution at the same dose. The learning and memory function, the activity of superoxide dismutase (SOD), the content of malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) were examined after the cabin training. The ultramicrostructures of hippocampus were also observed. RESULTS: (1) Compared with NC group, the number of working memory errors, the total errors, the content of hippocampus 8-OHdG and serum MDA in MS and MH groups were higher and the activity of serum SOD was lower (P<0.05). The hippocampus structure was destroyed and some degree of edema and more apoptosis in the neurons were obserued in MS group and MH group. (2) Compared with MS group, the number of working memory errors(WME), the total errors, the content of hippocampus 8-OHdG and serum MDA were lower and the activity of serum SOD was higher in MH group (P<0.05). In MH group, the morphology of hippocampus structures kept nearly normal arrangement and the only mild edema and fewer apoptosis in the neurons were found. CONCLUSION: Hydrogen may attenuate chronic hypoxia-hypercapnia-induced memory damage in rats by inhibiting apoptosis of the neurons and decreasing detrimental free radicals reaction.     

Transplantation of human amnion epithelial cells improves learning and memory function in Alzheimer's disease-like pathology rat model

AIM: To observe the treatment effect and its immune regulation of human amnion epithelial cells (hAECs) on Alzheimer's disease (AD)-like pathology rat model. METHODS: The hAECs were isolated from amnion with trypsin digestion, and the phenotype of hAECs was analyzed by flow cytometry. SD rats (n=48) were randomly divided into sham control group, model group, medium group and hAECs group. AD-like pathology rat model was induced by bilateral intraventricular injection of lipopolysaccharide (LPS). hAECs (5×10⁵) were injected into the hippocampus of the AD-like pathology rats. At 2 weeks after transplantation, the animals were tested by Morris water maze to observe the function of learning and memory. The pathological change of the brain was observed by HE staining. The expression of amyloid β-protein 42(Aβ42) and Tau protein and the level of acetylcholine (ACh) in the injury brain were determined by immunohistochemistry. The survival and differentiation of hAECs in the hippocampus were measured by immunofluorescent technique. The percentages of lymphocyte subsets in the peripheral blood mononuclear cells were analyzed by flow cytometry. The contents of serum cytokines were detected by cytometric bead array. RESULTS: Compared with model group and medium group, hAECs group showed shortened escape latency (P<0.01), increased frequency of going through the platform (P<0.05), reduced loss of hippocampal neurons, decreased expression of Tau protein and Aβ42 in the hippocampus (P<0.05), increased ACh level in the hippocampus (P<0.05), decreased percentages of Th1 and Th17 subsets, increased percentages of Th2 and Treg cells (P<0.05), decreased concentrations of IFN-γ and IL-2 in the serum, and increased concentration of IL-4(P<0.05). CONCLUSION: hAECs improve the cognitive learning and memory function and alleviate pathologic damage of hippocampus through immune regulation in AD-like pathology rats.     

Effects of extract of Ginkgo biloba on cognitive function and apoptosis of hippocampus neuronal cells in type 1 diabetic rats

AIM: To investigate the protective mechanism of extract of Ginkgo biloba (EGB) on apoptosis of hippocampus neuronal cells in type 1 diabetic encephalopathic rats. METHODS: Thirty-six male Sprague-Dauley rats were divided into 3 groups: control group, diabetic group and EGB-treated group. Streptozotocin was injected intraperitoneally to the animals in later two groups to induce diabetes. The rats in EGB-treated group were injected intraperitoneally with EGB, and the same volume of normal saline was injected to the rats in other groups. At the end of the 12th week, the spatial learning and memory abilities of rats in each group were examined by Morris water maze test. Blood glucose and serum insulin concentration were measured. The neuron densities in hippocampus were measured by Image-Pro Plus 6.0 software. The expressions of Bax, Bcl-2, caspase-3 were assayed by Western blotting and immunohistochemistry. RESULTS: Compared to control group, the level of blood glucose (P<0.01), the protein expression of Bax (P<0.01) and caspase-3 (P<0.01) in hippocampus neuronal cells, and the ratio of Bax/Bcl-2 (P<0.01) and the escape latency (P<0.01) in diabetic group, were significantly increased, while the serum insulin concentration (P<0.01), the neuronal density (P<0.05) in CA1,CA2 hippocampal regions and the platform searching score (P<0.01) were significantly deceased. After treated with EGB, the serum insulin concentration (P<0.05), the neuronal density (P<0.05) in CA1,CA2 hippocampal regions and the platform searching score (P<0.01) were significantly increased, while the level of blood glucose (P<0.01), the protein expression of Bax (P<0.05), caspase-3 (P<0.05) in hippocampus neuronal cells, the ratio of Bax/Bcl-2 (P<0.01) and the escape latency (P<0.05) were significantly deceased than those in diabetic group. The protein expression of Bcl-2 in hippocampus neuronal cells did not alter in any experimental rats. CONCLUSION: EGB improves the spatial learning and memory capacity in diabetic rats by decreasing the expression of Bax, Bax/Bcl-2 ratio and down-regulating caspase-3 to reduce neurocyte apoptosis and increase the neuron density in CA1, CA2 hippocampal regions, suggesting that effective regulation of neuron apoptosis associated genes may be one of the mechanisms for EGB to treat diabetic encephalopathy.     

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.     

Molecular mechanism of BMSC intracerebral transplantation in improving learning and memory abilities of AD mice

AIM: To investigate the effect of bone marrow mesenchymal stem cell (BMSC) transplantation on learning and memory abilities and pathological changes of Alzheimer disease (AD) mice and the molecular mechanisms. METHODS: C57/BL6 wild-type (WT) and transgenic (Tg) mice were randomly divided into 4 groups:WT/PBS group, WT/BMSCs group, Tg/PBS group and Tg/BMSCs group. The mice were administered with PBS or BMSCs via intracerebroventricular injection. Spatial learning and memory abilities of the mice were evaluated by Morris water maze test on the 3rd day after surgery. Real-time PCR was applied to detect the mRNA expression of CX3C chemokine ligand 1 (CX3CL1), CX3C chemokine receptor 1 (CX3CR1), IL-1β, TNF-α, Nurr1, YM1, insulin-degrading enzyme (IDE) and matrix metalloproteinase 9 (MMP9). The protein levels of CX3CL1 and Aβ42 were measured by ELISA. Western blot was used to detect the protein expression of postsynaptic density protein 95 (PSD95) and synaptophysin (SYP). RESULTS: The transplanted BMSCs were observed near the hippocampus of APP/PS1 mice on the 10th postoperative day. The escape latency of the mice in Tg/PBS group was significantly longer than that in the WT/PBS mice (P<0.05). Compared with Tg/PBS group, the escape latency of Tg/BMSCs group was significantly shorter (P<0.05), and the mRNA and protein levels of CX3CL1 in Tg/BMSCs group were significantly higher than those in Tg/PBS group (P<0.01). The results of immunohistofluorescence staining showed that BMSC transplantation promoted the activation of microglia in the brain of WT and Tg mice. The mRNA expression of YM1 was up-regulated in WT/BMSCs group and Tg/BMSCs group (P<0.05). Compared with WT/PBS mice, the mRNA expression of TNF-α in the cortex and hippocampus of Tg/PBS group was significantly increased (P<0.05), and the mRNA expression of Nurr1 in the cortex was significantly decreased (P<0.01). Meanwhile, the mRNA expression of TNF-α in the cortex of Tg/BMSCs mice was decreased (P<0.01) and the mRNA expression of CX3CR1 and Nurr1 was up-regulated compared with Tg/PBS group (P<0.05). The results of Western blot showed that the protein levels of PSD95, p85, p110 and p-Akt in Tg/BMSCs group were significantly higher than those in Tg/PBS group (P<0.05). Finally, BMSC transplantation reduced the protein level of Aβ42 in APP/PS1 mice (P<0.05), and increased the mRNA expression of IDE and MMP9 in the hippocampus (P<0.05). CONCLUSION: BMSC transplantation modulates neuroinflammatory responses and promotes neuroprotective factor and synaptic protein expression, thus improving the learning and memory abilities in the APP/PS1 mice, which may be achieved by up-regulating the expression of CX3CL1.     

Effect of Zhengtian pills on P2X3 receptor expression in trigeminal gan-glion of migraine rats

AIM: To explore the effect of Zhengtian pills on P2X₃ receptor expression in trigeminal ganglion (TG) of migraine rat. METHODS: Sprague-Dawley (SD) rats were randomly divided into control group, migraine group, Zhengtian pills (ZTP) group and A-317491 group. After given corresponding drugs for 7 d, migraine rat model was established by subcutaneously injection of nitroglycerin (10 mg/kg), while the control rats were injected with saline. The beha-vioral manifestations of the rats were observed. The expression of P2X₃ receptor in rat TG was detected by the methods of immunofluorescence, Western blot and rea-time PCR. RESULTS: About 5 min after subcutaneousl injection, the behavioral manifestations such as scratching head and climbing cage were observed. The behavioral manifestations were observed within the first 30 min in control group, but the erythroid ears did not appear. After 2 h of molding, the behavioral manifestations disappeared in ZTP group and A-317491 group, while those in migraine group lasted for 3 h. Immunofluorescence results showed that the expression of P2X₃ receptor in TG was positive in each group. The expression level in migraine group was significantly higher than that in other groups. The P2X₃ receptor protein and mRNA levels in the TG of migraine group were higher than those in control group (P<0.01), while those in ZTP group were lower than those in migraine group (P<0.01). No difference of the P2X₃ receptor expression between ZTP group and A-317491 group was observed. CONCLUSION: Zhengtian pills may effectively alleviate migraine by inhibiting the expression of P2X₃ receptor in TG.     

Neuroprotective effect of novel Rho kinase inhibitor FSD-C10 on a mouse model of Alzheimer disease

AIM: To explore the neuroprotective effect of novel Rho kinase inhibitor FSD-C10 on Alzheimer disease (AD) model of APP/PS1 double transgenic (Tg) mice. METHODS: Male APP/PS1 Tg mice (n=20) at 8 months of age were randomly divided into 2 groups:model group and FSD-C10 treatment group. The mice were treated with normal saline or FSD-C10 (25 mg·kg^-1·d^-1) by intraperitoneal injection, once daily for 2 months. Age-and sex-matched wild-type (WT) mice without treatment were used as the control. The Morris water maze (MWM) test and SMART 3.0 behavioral record system were applied to examine and analyze the spatial cognitive function of the mice. The protein levels and distribution of Aβ, p-tau and synapse-associated proteins such as synaptophysin, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and postsynaptic density protein 95 (PSD-95) were determined by immunofluorescence staining. The protein levels of phosphorylated amyloid precursor protein at Thr668[p-APP(Thr668)], beta-site APP-cleaving enzyme 1 (BACE1) and synapse-associated proteins in the brain were analyzed by Western blot. RESULTS: Compared with model group, FSD-C10 treatment significantly improved the cognitive function of the APP/PS1 Tg mice, accompanied by reduced Aβ deposition and p-tau level, increased protein level of p-APP (Thr668) in the central nervous system, decreased expression of BACE1, and increased expression of synapse-associated proteins in the brain of the mice (P<0.05). CONCLUSION: FSD-C10 has neuroprotective potential in the APP/PS1 Tg mice. The mechanism may be related to enhancing the non-amyloidogenic APP cleavage pathway, reducing the production of Aβ oligomers, the deposition of senile plaques and the amount of tau protein, up-regulating synapse-associated proteins, and increasing synaptic plasticity.     

Effects of rolipram on learning and memory and the activity of PDE4 in hippocampus following the focal brain injury induced by ischemia- reperfusion in rats

AIM: To investigate the effects of rolipram on the ability of learning and memory and the activity of PDE4 in hippocampus following the focal brain injury induced by ischemia- reperfusion in rats. METHODS: The cerebral ischemia-reperfusion injury model was made by middle cerebral artery occlusion (MCAO) in rats. The rats were randomly divided into sham-operated group, model group, and rolipram group. Rolipram was administered once a day (1 mg/kg, ip) from 6 h after the onset of the operation for 2 weeks. Then the learning and memory abilities were tested after Morris water maze and step-though training. The activity of PDE4 in hippocampus was evaluated by HPLC. RESULTS: In the Morris water maze test, compared to sham-operated group, the platform-finding time and swimming distance in model group were significantly longer (P<0.05). Compared to model group, the platform-finding time and swimming distance in rolipram group were significantly shorter (P<0.05). In the step-through test, compared to sham-operated group, the lantent period in model group was significantly shorter (P<0.01) and the error times were statistically increased(P<0.05). Compared with model group, the lantent period in rolipram group were significantly longer (P<0.05), and the error times were markedly decreased. The assay of the HPLC demonstrated that the activities of PDE4 in hippocampus in model group were higher than those in the sham-operated group and rolipram group. CONCLUSION: Rolipram reduces the activity of PDE4 in hippocampus and enhances the ability of learning and memory after the injury induced by ischemia-reperfusion.     

Effect of chronic intermittent hypoxia on memory and CREB expression in growing rats

AIM: To observe the alterations in cognition of growing rats exposed to chronic intermittent hypoxia (CIH) and to explore its underlying mechanisms. METHODS: Forty male Sprague-Dawley rats (3-week-old～4-week-old and 80 g to 100 g), which had been trained to complete the 8-arm (4-arm baited) radial maze, were randomly divided into 4 groups: 2-weeek-CIH group (2IH), 4-week-CIH group (4IH), 2-week-control group (2C) and 4-weeek-control group (4C). The intermittent hypoxia model was induced by putting the animals in an intermittent hypoxia cabin. When intermittent hypoxia was terminated, spatial memory of these growing rats was tested by 8-arm (4-arm baited) radial maze task, then, one rat in each group was randomly selected for ultrastructural observation. The hippocampus and prefrontal cortexes of the rats were collected for analyzing the mRNA and protein expression of CREB by RT-PCR and Western blotting, respectively. RESULTS: (1) In the 8-arm (4-arm baited) radial maze task, the results indicated that the rats in the 4 groups displayed significant difference in their performance assessed by three measuremens: the reference memory error, the working memory error and total memory error (P<0.05, respectively). (2) Early apoptosis and destructure of the neurons in the hippocampus and prefrontal cortex were observed under electron microscope in CIH exposed groups, especially in 4IH group, but not detected in 2C and 4C groups. (3) The expression levels of CREB mRNA and p-CREB protein in 2IH and 4IH groups were less than those in 2C and 4C groups in the hippocampus and prefrontal cortex (P<0.05, respectively), especially in the hippocampus of 4IH group (P<0.01). No difference was found within control groups (P>0.05, respectively). CONCLUSION: Exposure to experimentally-induced IH in growing rats is associated with time related spatial memory impairment. Chronic intermittent hypoxia leads to the disorders of neuron ultra-structure in memory related brain regions. It also inhabits the CREB transduction, expression and CREB phosphorylation, decreases the synthesis of the memory related protein. These factors maybe contribute to learning-memory impairment of growing rats exposed to chronic intermittent hypoxia.     

Protective effect of paeoniflorin on nerve cells in APP/PS1 mice and its mechanism

AIM: To investigate the therapeutic and preventive effects of paeoniflorin (PF) on APP/PS1 mice, and to explore the possible mechanism. METHODS: Fifteen male 5-month-old APP/PS1 non-dominant mice were chosen as normal control group, 15 male 5-month-old APP/PS1 double transgenic mice were used as model group, and 15 male 5-month-old APP/PS1 double transgenic mice treated with 5 mg/kg PF by intraperitoneal injection were allocated in administation group. The learning and memory ability of the mice in each group was detected by Morris water maze. The apoptosis was assessed by TUNEL fluorescence staining. The protein expression of PI3K, Akt, p-PI3K, p-Akt, caspase-3, caspase-9, Bcl-2 and Bax in cerebral cortex and hippocampus was detected by Western Blot. The protein expression levels and distribution of caspase-3 and caspase-9 were detected by immunohistochemistry. RESULTS: (1) Compared with normal control group, the learning and memory ability declined in APP/PS1 model group. Compared with APP/PS1 model group, PF obviously improve the ability of learning and memory in mice. (2) Compared with normal control group, the apoptosis of nerve cells in APP/PS1 model group significantly increased and distributed in wider areas, while that in PF group was reduced (P<0.05). (3) Compared with APP/PS1 model group, PF could significantly lower pro-apoptotic factors, caspase-3, caspase-9 and Bax (P<0.05), and increase the expression of anti-apoptotic factors, p-PI3K, p-Akt and Bcl-2 (P<0.05). CONCLUSION: PF can up-regulate the expression of Bcl-2 and down-regulate the expression levels of caspase-9, caspase-3 and Bax via the activation of PI3K/Akt pathway, thereby inhibiting the nerve cell apoptosis and protecting the nerve cells, so as to treat neurodegenerative diseases.