Effect of glucagon-like peptide-1(7-36)NH2 on insulin secretion and membrane potentials of pancreatic islet β-cells

AIM: To observe pathomorphological changes in cerebral cortex and hippocampus in the mouse with synthetic vascular dementia. METHODS: The synthetic vascular dementia model was produced in the mouse. Animals were killed 7 d, 15 d, and 30 d after the operation, brain tissues were removed and embedded in paraffin. Section of 8μm thickness were stained with hematoxylin-eosin(HE) and Nissl methods, and observed with light microscope. RESULTS: The cerebral cortex in the mouse became thinner on the seventh day, karyopyknosis in partial nervous cells was formed, the number of local neurons was reduced, sieve structure was observed, and glial cells proliferated, with the similar results 15 d and 30 d after operation. Model mouses hippocampal cells in CA₁ area were reduced and almost disappeared 30 d after operation. At the same time, glial cells were abundantly proliferated, tubercles were formed. Cells in CA₂, CA₃ area were also reduced and hippocampal sclerosis occurred. CONCLUSION: Delayed necrosis of hippocampal pyramidal cells may be the pathological basis of ischemia cerebral vascular dementia.     

Relation between astroglial activation state and ischemic tolerance in the gerbil hippocampus

AIM:To observe the relation between astroglial activation state and ischemic tolerance in the gerbil hippocampus. METHOD: Bilateral occlusion of common carotid arteries and immunofluorescent methods in the gerbil hippocampal tissue. Slices were used. The morphological changes of the neurons were observed by light microscopy.RESULTS:Pretreatment with 2 minute bilateral carotid artery occlusion produced protective effects of CA₁ neurons. Glial fibrillary acidic protein (GFAP) staining showed weak positive cells in control group. Most of GFAP positive cells showed weak and middle positive cells after recirculation 1d and 2d following ischemic 3.5 min and preconditioning of the brain with sublethal ischemia respectively.CONCLUSION:Astroglial played an important role in cerebral ischemia. It is possible that state of astroglial activation related to neuronal survival in ischemic tolerance.     

Preliminary separation and identification of quiescent and activated neural stem cells in mouse embryonic cerebral cortex

AIM To isolate and identify quiescent and activated neural stem cells from mouse embryonic cerebral cortex. METHODS Two cell clusters derived from mouse cerebral cortex on embryonic day 14.5 were separated by flow cytometry. The expression of stem cell marker Pax6 and proliferation marker Ki67 was examined by immunofluorescence. The mRNA expression of stem cell marker genes Pax6, Oct4, Sox2 and Nanog were detected by RT-qPCR. Cell cycle was analyzed by flow cytometry and RT-qPCR. Proliferation ability was investigated by in vitro cell culture. RESULTS In both 2 groups, the cells expressed Pax6. Immunofluorescence staining of Ki67 in the big cell group was positive, while that in small cell group was negative. Cell cycle assay showed that the proportion of G₀/G₁ phase in the small cells was higher than that in the big cells, the G₂/M phase proportion was 0, and the expression of cyclin A and cyclin B was lower than that in the big cells (P<0.05). When cultured in vitro, the number of microspheres formed by the small cells was smaller and the formation speed was slower than those of the big cells. After digestion of microspheres, Pax6 and Ki67 staining of both big and small cells was positive, and the positive rates were not different (P>0.05), indicating that the quiescent neural stem cells were activated. CONCLUSION The 2 cell clusters are quiescent and activated state of neural stem cells. The activated stem cells have strong abilities of self-renewing and proliferation, while these abilities of quiescent stem cells are poor. The quiescent stem cells can translate into activated ones when cultured in vitro for a period.     

Transforming growth factor beta 1 reduces spontaneous recurrent seizures and inhibits activation of glial cells in rats

AIM: To investigate the mechanism that intranasal transforming growth factor beta 1 (TGF-β₁) reduces the occurrence of spontaneous seizures after status epilepticus (SE) induced by pilocarpine. METHODS: The rats received recombinant human TGF-β1 or the same volume of PBS, and were treated with pilocarpine to induce SE. All the rats were put into a special cage for video monitoring 7 days later. The determinations of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba1) positive cells by the method of immunohistochemistry were performed to evaluate the activation levels of the gliocytes in hippocampus. The neuron loss was measured by Nissl staining. RESULTS: TGF-β₁ reduced the average frequency, severity and duration of spontaneous seizures. The activated glia cells in the hippocampus were significantly reduced in TGF-β₁ group compared with pilocarpine group at 14 days after SE (P<0.05). TGF-β₁ significantly attenuated the loss of pyramidal neurons in hippocampal CA3 area at 14 days after SE (P<0.01). CONCLUSION: Intranasal TGF-β₁ reduces spontaneous recurrent seizures by inhibiting the activation of glia cells and attenuating the loss of pyramidal neurons.     

Saikosaponin a inhibits PTZ-induced activation of hippocampal astrocytes in mice

AIM: To investigate the inhibitory effect of saikosaponin a (SSa) on pentylenetetrazole (PTZ)-induced activation of hippocampal astrocytes in mice. METHODS: Hippocampal astrocytes were isolated and cultured. The cells were randomly divided into control group, PTZ group, PTZ+0.625 mg/L SSa group and PTZ+1.25 mg/L SSa group. The cells were identified by detection of glial fibrillary acidic protein (GFAP). The cell viability was measured by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of GFAP and connexin 43 (Cx43) was mea-sured by ELISA. The level of apoptosis was determined by flow cytometry and Hoechst 33258 staining. RESULTS: The primary hippocampal astrocytes grew by adherent culture, and the processes of the astrocytes were obvious. Immunofluorescence showed positive GFAP expression in the astrocytes. Compared with control group, the viability of the cells and the percentage of the cells in G₂/M phase in PTZ group were significantly increased (P<0.05), and the expression of GFAP and Cx43 was also markedly increased (P<0.05). Compared with PTZ group, the viability of the cells and the percentage of the cells in G₂/M phase were obviously decreased in PTZ+0.625 mg/L SSa group and PTZ+1.25 mg/L SSa group, and the expression of GFAP and Cx43 was also reduced, whereas the percentage of apoptotic cells was significantly increased (P<0.05).CONCLUSION: SSa significantly suppresses PTZ-induced activation of hippocampal astrocytes, inhibits the cell proliferation and induced apoptosis.     

The changes in proliferation and apoptosis of macrophages in the development of pulmonary fibrosis of rats

AIM: To observe the changes in proliferation and apoptosis of macrophages in the development of pulmonary fibrosis in rats. METHODS: The number of macrophages, apoptotic cells, the proliferation index (PI) and MTT activity of macrophages were assayed on the day 14 and the day 30 after intratracheal adminstration BLMA₅ in rats. RESULTS: (1) The number of alveolar macrophages was increased in BLMA₅ 14 d group and in BLMA₅ 30 d group, compared with sham 14 d group and sham 30 d group, respectively. The number of macrophages in BLMA₅ 14 d group was higher than that in BLMA₅ 30 d group. (2) The PI of macrophages increased in BLMA₅ 14 d group, and decreased in BLMA₅ 30 d group. (3) The number of apoptotic cells increased both in BLMA₅ 14 d group and BLMA₅ 30 d group. The number of apoptotic cells in BLMA₅ 14 d group was lower than that in BLMA₅ 30 d group. (4) The MTT activity of macrophages was higher in BLMA₅ 14 d group and in BLMA₅ 30 d group than that in sham 14 d group and sham 30 d group, respectively. CONCLUSIONS: The ability of proliferation increased at first, and then decreased, but the apoptosis of macrophages increased all the time, in the development of pulmonary fibrosis. This might be partly contributed to the changes of the number and function of macrophages in lung.     

Dynamic expressions of synapsin I and phosphorylated synapsin I in hippocampus of vascular dementia rats

AIM: To observe the dynamic changes of synapsin I expression and its phosphorylation in hippocampus in vascular dementia (VD) rats. METHODS: Eighty SD rats were randomly divided into sham-operated group (n=40) and VD model group (n=40), and the latter were established by repeatedly clipping the common carotid arteries with an intraperitoneal injection of sodium nitroprusside solution in anesthetized condition. The synaptic ultrastructural changes in hippocampal CA1 region and the expression levels of synapsinⅠ and phosphorylated synapsinⅠin hippocampus were observed by TEM and immunohistochemical staining method respectively in both sham-operated group and VD model group at 15 d, 1 month, 2 months and 4 months time points. RESULTS: No obviously pathological changes to CA1 area synapse were found in SO group. In model group rats, synaptic circa membrane ambiguity and fusion, synaptic circa membrane structure decreased the postsynaptic density, reduced synaptic vesicles and vesicle cluster. Above pathological changes became gradually severe along with the time prolongation after model-making operation. Compared with sham-operated group, the expression of synapsin I significantly reduced in CA1 region (P<0.01). However, no significant change in molecular layer of DG region (P>0.05) in model group was observed. The number of p-synapsin I positive neurons in DG and hippocampal CA1 region was less in model group than that in sham-operated group (P<0.05, P<0.01). The average absorbance values of p-synapsin I positive neurons in DG and hippocampal CA1 region in model group were decreased at 15 d and 1 month time points (P<0.01), but increased in CA1 region (P<0.01) and unchanged in DG at 2 months and 4 months time points (P>0.05). CONCLUSION: The damaged synaptic structure and depressed expression of synapsin I and its phosphorylation in presynaptic parts of hippocampus induced by repeatedly cerebral ischemia/reperfusion may contribute to the synaptic transmission disorders, especially the presynaptic disorder which may be one of the important pathogenesis of the initiation and development in vascular dementia rats.     

Effect of dexmedetomidine on astrocytes in rats with focal cerebral ischemia-reperfusion

AIM: To investigate the effects of dexmedetomidine on astrocytes in rats with focal cerebral ischemia-reperfusion. METHODS: Sixty female SD rats, weighing 230~250 g, were randomly divided into sham operation group, ischemia-reperfusion group, dexmedetomidine preconditioning group 1 and dexmedetomidine preconditioning group 2. The model of middle cerebral artery occlusion (MCAO) was established by thread embolism of middle cerebral artery. In sham operation group, the carotid arteries were exposed without performing MCAO. In ischemia-reperfusion group, NS was injected intraperitoneally 30 min before focal cerebral ischemia-reperfusion. The rats in dexmedetomidine preconditioning group 1 and dexmedetomidine preconditioning group 2 received intraperitoneal injection of dexmedetomidine at doses of 20 μg/kg and 40 μg/kg, respectively. The neurological scores were studied, and the pathological changes were observed under microscope with HE staining. The expression of glial fibrillary acidic protein (GFAP) and tumor necrosis factor α (TNF-α) in astrocytes was detected by the methods of immunohistochemistry and immunoblotting 24 h after cerebral ischemia-reperfusion. RESULTS: No neurological change was observed in sham operation group. The neurological deficiency scores in ischemia-reperfusion group were markedly higher than those in dexmedetomidine preconditioning group 1 and group 2 (P<0.05). Compared with sham operation group, the expression of GFAP and TNF-α in astrocytes and the level of GFAP increased significantly 24 h after focal cerebral ischemia-reperfusion. Pretreatment with dexmedetomidine significantly attenuated the expression of GFAP and reduced the infarct size and inflammation. CONCLUSION: Dexmedetomidine has a neuroprotective effect on focal cerebral ischemia-reperfusion injury by inhibiting the astrocytes.     

The augmentative effect of inducible nitric oxide synthase on pulmonary fibrosis progression

AIM: To study the up-regulation of inducible nitric oxide synthase (iNOS) in lung of pulmonary fibrosis and its relationship with fibrosis. METHODS: The changes of amount of iNOS positive stain cells and type Ⅰ?Ⅲ collagen were examined on the day 7, 14 and 30 after intratracheal administration of bleomycin A₅. The contents of NO₂^-/NO₃^- (nitrite/nitrate) in out-flowing pulmonary blood (OPB), hydroxyproline in lung and the histological changes were detected after iNOS was blocked by aminoguanidine (AG). RESULTS: (1) The number of iNOS-positive stain cells increased significantly in BLMA₅ 7 d, 14 d and 30 d groups compared with that in control group (P<0.01). Furthermore, the increment of the number of iNOS-positive stain cells in BLMA₅ 7 d, 14 d groups was more than that in BLMA₅ 30 d group. There was an increment of collagen in BLMA₅ 14 d group and in BLMA₅ 30 d group , with an increase in type Ⅲ collagen in BLMA₅ 14 d group and an increase in type Ⅰcollagen in BLMA₅ 30 d group. (2) The high level of NO₂^-/NO₃^- in OPB and hydroxyproline level in lung could be reversed by AG, a selective inhibitor of iNOS. Large amount of fibroblasts and macrophages were also abated by AG. CONCLUSION: In the development of pulmonary fibrosis, the expression of iNOS is up-regulated, which induces nitric oxide (NO) production and promotes propagation of pulmonary fibrosis.     

Effects of flavonoids isolated from Scutellaria stem and leaf on expression of NMDAR and VEGF in chronic cerebral ischemia rats

AIM: To study the effects of flavonoids isolated from Scutellaria stem and leaf (SSF) on the expression of N-methyl-D-aspartate receptor (NMDAR) and vascular endothelial growth factor (VEGF) in chronic cerebral ischemia rats. METHODS: The model of chronic cerebral ischemia was established by bilateral carotid artery occlusion for 2 months in female SD rats. The effects of SSF on mRNA expression of NMDAR in hippocampus and VEGF in cerebral cortex were evaluated by the method of RT-PCR. RESULTS: Compared with the sham group, the expression of NMDAR1, NMDAR2A and NMDAR2B in hippocampus and VEGF in cerebral cortex were significantly increased (P<0.01). However, the cerebral ischemia rats daily and orally administered with SSF at doses of 17.5 mg·kg^-1·d^-1, 35 mg·kg^-1·d^-1 and 70 mg·kg^-1·d^-1 for 38 days appeared that the mRNA expression of NMDAR1, NMDAR2A and NMDAR2B in hippocampus was obviously reduced (P<0.05), and the mRNA content of VEGF in the cortex (P<0.05) was increased. CONCLUSION: SSF decreases the expression of NMDAR in hippocampus, increases the expression of VEGF in cerebral cortex of cerebral ischemia rats, suggesting that the neuroprotective effect of SSF may be exerted by influencing the production of NMDAR and VEGF in the brain.     

Effect of calcitonin gene-related peptide on proliferation of vascular smooth muscle cells

AIM: To elucidate the effect of calcitonin gene-related peptide (CCRP) in the therapy of atherosclerosis.METHODS:Effect of CGRP on cell cycle kinetics of cultured vascular smooth muscle cells(HA-VSMC) was investigated by flow cytometry. The expression of cyclins D₁ and E required for initiation of S phase were also studied by immunochemistry method. RESULT: CGRP was shown to arrest VSMC in the G₀/G₁ phase of cell cycle and reduced expression of cyclins D₁ and E. CONCLUSION:CGRP inhibits proliferation of HA-VSMC by arresting cells in G₁ phase via limiting accumulation of cyclin D₁ and E. It might play a role in the therapy of atherosclerosis.     

Ellagic acid attenuates hypoxic-ischemic brain injury by alleviating autophagy

AIM:To investigate whether ellagic acid (EA) attenuates hypoxic-ischemic encephalopathy (HIE) by down-regulating autophagy. METHODS:In vivo, Sprague-Dawley rats (n=17) were randomly divided into 3 groups:5 rats for sham group, 6 rats for HIE group and 6 rats for HIE+EA pretreatment group. The rats in HIE+EA pretreatment group were treated with EA (10 mg/kg, 10 mL/kg, suspended in corn oil, ig). After 24 h of operation, the rats from each group were sacrificed and their brains were collected. TTC staining and HE staining were used to define the infarct areas and brain structure. The autophagy-related proteins beclin-1, P62, LC3-Ⅱ/-I and Atg5 in the cortex in each group were compared by Western blot. In vitro, PC12 cells were divided into 3 groups:control group, CoCl₂ group and CoCl₂+EA pretreatment group. CoCl₂ at 800 μmol/L was added to the PC12 cells to induce an anoxic environment. The PC12 cells were pretreated with EA at 8 μmol/L and the cell viability was measured by CCK-8 assay. The production of reactive oxidative species (ROS) in the cells was detected by flow cytometry with DCFH-DA staining. MDC staining and TMRE staining were applied to reflect the extent of autophagy and the state of apoptosis, respectively. The autophagy-related proteins in PC12 cells were also investigated. RESULTS:In HIE group, 7-day-old rats were given the operations and the their large infarct areas in the hemisphere were observed by TTC staining. HE staining displayed the injured hemispheres which contained few neurons, and exhibited edema status and serious structural damage. EA pretreatment decreased the infarct area and alleviated the damage to hemisphere with more visible neurons, compared with HIE group. Compared with sham group, the levels of autophagy-related proteins Atg5, beclin-1 and LC3-Ⅱ/-I in the cortex were increased (P<0.01), and P62 protein expression was decreased (P<0.01) in HIE group. Compared with HIE group, the protein expression of Atg5, beclin-1 and LC3-Ⅱ/-I was decreased (P<0.01) and P62 protein expression was increased in HIE+EA pretreatment group (P<0.01). In vitro, compared with CoCl₂ group, the PC12 cells in CoCl₂+EA pretreatment group showed a lower ROS level. Moreover, the cells in CoCl₂+EA pretreatment group exhibited higher mitochondrial membrane potential than that in CoCl₂ group. MDC staining in CoCl₂ group showed high value of fluorescence and increased number of autophagosomes. EA pretreatment reduced the number of autophagosomes and the extent of autophagy to protect PC12 cells. Furthermore, the protein levels of Atg5, beclin-1 and LC3-Ⅱ/-I in CoCl₂ group were higher (P<0.01), and the protein expression of P62 was lower (P<0.01) than those in control group. In CoCl₂+EA pretreatment group, the protein levels of Atg5, beclin-1 and LC3-Ⅱ/-I were decreased (P<0.01) and the protein expression of P62 was increased as compared with CoCl₂ group (P<0.01). CONCLUSION:EA pretreatment attenuates autophagy to protect the neurons against HIE injury.     

Effects of puerarin on neurological function,and synaptic morphological structure and parameter of cerebral cortex in cerebral ischemia-reperfusion rats

AIM: To investigate the protective effect of puerarin (Pue) on the neural function in a rat model of cerebral ischemia-reperfusion (IR) injury by observing synaptic morphological structural alterations and the parameter variations in brain cortex. METHODS: Male SD rats (n=69) were randomly divided into sham operation group (sham group, n=15), model group (IR group, n=18), Pue group (n=18) and nimodipine (NIM) positive control group (NIM group, n=18). The model of cerebral IR injury was established by a suture method. After ischemia for 2 h and reperfusion for 24 h, the rats in Pue group and NIM group were injected with Pue at 8 mg·kg^-1·d^-1 and NIM at 1 mg·kg^-1·d^-1, respectively, while the rats in sham group and IR group were injected with the same volume of saline. The modified neurological severity scores were evaluated at 3, 7 and 14 d, the ultrastructural changes of the synapses at the ischemic side of cerebral cortex were observed under transmission electron microscope, and the postsynaptic density was analyzed by Quantiment-520 image analysis software. RESULTS: Compared with IR group, the scores of neurological deficit were both reduced in Pue group and NIM group (P<0.05), and the difference between Pue group and NIM group was not obvious. The presynaptic and postsynaptic membranes and synaptic cleft were indistinct under electron microscope in IR group, the number of synaptic vesicles in presynaptic component was reduced, and the density of postsynaptic dense zone was decreased. The synapses were dense in Pue group and NIM group compared with IR group, the dented synapses were increased, 2 active synapses were often presented, postsynaptic density was incrassated and the synaptic cleft was clear. The curvature of synaptic interface was increased, the postsynaptic density was thickened, and the synaptic cleft was narrow in ischemic penumbra (P<0.05). The parameters of synaptic morphological structure at 7 d and 14 d were better than those at 3 d (P<0.05). CONCLUSION: The treatment with Pue promotes neural functional recovery against cerebral IR injury in the rats, which may be related to restore synaptic structure.     

The alteration of extracellular sodium and potassium ionic activities of hippocampal neurons in epileptiform rats kindled by coriaria lactone

AIM and METHODS: The sodium ion Na⁺ and potassium ion K⁺ selective microelectrodes were used to measure changes of ionic activity of extracellular sodium and potassium( [Na⁺]_o, [K⁺]_o) in hippocampus and hippocampal slice during epieptic seizure induced by intrahippocampal microinjection of coriaria lactone(CL) in rats and perfusing hippocampal slice with CL. RESULTS:30 s, 1min and 2min after injection of CL into hippocampus, the [Na⁺]_o decreased 27.7 mmol/L, 50.3 mmol/L, 57.8 mmol/L respectively and the [K⁺]_o increased 2.3 mmol/L, 2.4 mmol/L, 2.9 mmol/L respectively compared with control values(P＜0.01). The [K⁺]_o returned to the control level 3min after local application of CL, but the[Na⁺] _o was still lower than that of control group(P＜0.01). The [Na⁺]_o and the [K⁺]_o were measured also in hippocampal silces and results are similar to those of experiments in vivo. CONCLUSION: The influx of Na⁺and the flux of K⁺occurred during epileptiform discharges of hippocampal neurons induced by administration of CL.     

Cytological characteristics and gene micro-array analysis of a mouse brain microvascular endothelial cell strain: bEnd.3

AIM: To study the cytological characteristics and gene expression of normal cultured bEnd.3, a mouse brain microvascular endothelial cell strain. METHODS: The morphology of bEnd.3 was studied by light and electronic microscopy, its molecular markers were observed by immunocytochemistry. Cell proliferation kinetics and apoptosis were analyzed by flow cytometry and MTT assay, PGE₂ level was measured by ELISA, and expression of the genes that closely related with vascular endothelial functions was studied by gene micro-array. RESULTS: bEnd.3 had morphological characteristics of microvascular endothelial cells (MVEC) growing in a cobblestone pattern, forming tube-like structure or capillary network and having microvilli. Furthermore, bEnd.3 showed positive staining for vW factor and CD34 and secreted high level of PGE₂ (644.55±30.24 ng/L). Gene micro-array analysis showed CD31, CD36, CD105 expression, and other genes closely related to microvascular endothelial functions also expressed at relatively high level. In addition, bEnd.3 responsed sensitively to mitogen such as basic fibroblast growth factor. CONCLUSION: bEnd.3 is a kind of MVEC, and it can be utilized to study the mechanisms of some diseases such as cancers and cardio- cerebral vascular diseases.     

Glutamate transport across blood brain barrier after transient global ischemia/reperfusion in rats

AIM: to study the change of glutamate(Glu) transport across blood brain barrier(BBB) in rat following forebrain ischemia/reperfusion. METHODS: BBB unidirectional transfer constant(K_i) for [³H]-Glu in rat hippocampus, cerebral cortex and striatum were determined after rats were subjected to cerebral ischemia 10 min (two-carotid occlusion plus hypovolemic hypotension) followed by 0.17, 2, 6 and 24 h of reperfusion. The recovery of [³H]-Glu in cerebrum was also determined after intracerebral injection of [³H]-Glu in another experiment. RESULTS: Compared with control rat brain, K_i for [³H]-Glu significantly(P＜0.05) decreased at 10 min cerebral ischemia followed by 0.17, 2 and 6 h of reperfusion. At 5 min after intracerebrally injecting [³H]-Glu, recovery of [³H]-Glu in control rat brain was 23.83%. The result indicted that there is a Glu efflux mechanism on BBB. This efflux was not significantly inhibited by pretreatment of 200 mg/L probenecid. After 10 min cerebral ischemia followed by 2 h of reperfusion, the recovery(13.13%) was significantly lower than contro(P＜0.05), its recovery was only 55% of the control. The result indicated that cerebral ischemia/reperfusion may enhanced the efflux of [³H]-Glu from brain. CONCLUSION: Cerebral ischemia/reperfusion significantly reduced Glu BBB transport from plasma to brain and enhanced efflux of Glu from brain.     

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.     

Effect of senegenin on H2O2-induced damage in hippocampal neurons of SD rats

AIM: To observe the effect of senegenin (Sen) on hippocampal neuron injuries induced by H₂O₂.METHODS: Hippocampal neurons were isolated from neonatal SD rats. The primarily cultured neurons were divided into control group, H₂O₂ group, Sen group and Sen+H₂O₂ group. The cell viability, the content of malondialdehyde(MDA) and the activity of superoxide dismutase(SOD) in the neurons were detected after treated with Sen. The morphological changes of nucleus of the neurons were observed by Hoechst 33258 staining. The mRNA expression of bcl-2 and bax was quantified by real-time PCR. The protein levels of Bcl-2 and bax were measured by Western blotting. The activity of caspase-3 was also assayed.RESULTS: Compared with H₂O₂ group, the levels of antioxidative enzyme were increased in Sen+H₂O₂ group (P<0.05). In addition, mRNA expression of bcl-2 increased and that of bax decreased (P<0.05) in Sen+H₂O₂ group. Moreover, Sen increased the protein level of Bcl-2, and reduced the protein level of Bax and the activity of caspase-3 in the neurons exposed to H₂O₂ (P<0.05).CONCLUSION: The protective effect of Sen on hippocampal neurons with H₂O₂ -induced injury may be involved in the mechanisms of     

Changes of plasma endothelin-1 and von Willebrand factor in patients undergoing cerebral digital substration angiography

AIM: To investigate the effects of cerebral digital substration angiography (DSA) on the expression of endothelin-1(ET-1) and von Willebrand factor(vWF) in vascular endothelial cells from the patients with ischemic cerebrovascular disease. METHODS: The plasma levels of ET-1 and vWF were measured by enzyme-linked immunosorbent assay in 108 patients before, immediately and 24 h after cerebral DSA. RESULTS: The plasma level of endothelin-1 significantly increased immediately and 24 h after cerebral DSA as compared with that before the procedure (P<0.05). The level of vWF was not changed before and after operation. CONCLUSION: The marked and sustained increase in endothelin-1 plasma level after cerebral DSA is probably related to mechanical endothelial injury by the procedure of cerebral DSA.