OBJECTIVETo investigate the cell proliferation and differentiation in the developing brain of mouse.

METHODSC57/BL6 mice were divided into 3 groups at random. Bromodeoxyuridine (BrdU) was injected into the brains in different development periods once a day for 7 d. The brains were retrieved 4 weeks after the last BrdU injection. Immunohistochemical and immunofluorescent studies were carried out for detecting cell proliferation (BrdU) and cell differentiation (NeuN, APC, Iba1, and S100beta), respectively.

RESULTSThe number of BrdU labeled cells decreased significantly with the development of the brain. Cell proliferation was prominent in the cortex and striatum. A small portion of BrdU and NeuN double labeled cells could be detected in the cortex at the early stage of development, and in the striatum and CA of the hippocampus in all groups. The majority of BrdU labeled cells were neuroglia, and the number of neuroglia cells decreased dramatically with brain maturation. Neurogenesis is the major cytogenesis in the dentate gyrus.

CONCLUSIONThese results demonstrated that cell proliferation, differentiation and survival were age and brain region related.

Animals ; Animals, Newborn ; Brain ; cytology ; growth & development ; Bromodeoxyuridine ; Cell Count ; Cell Differentiation ; physiology ; Cell Proliferation ; Cerebral Cortex ; cytology ; growth & development ; Corpus Striatum ; cytology ; growth & development ; Fluorescent Antibody Technique ; Hippocampus ; cytology ; growth & development ; Male ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins ; metabolism ; Neuroglia ; cytology ; physiology ; Neurons ; cytology ; physiology ; Nuclear Proteins ; metabolism

Animals ; Dibutyl Phthalate ; toxicity ; Female ; Hippocampus ; cytology ; growth & development ; Male ; Mitochondrial Proton-Translocating ATPases ; metabolism ; Neurons ; drug effects ; metabolism ; Pregnancy ; Rats ; Rats, Wistar

The objective of present study is to investigate the effect of human cytomegalovirus (HCMV) infection on human hippocampus neural stem cells NSCs differentiation in vitro, Fetal hippocampus tissue was dissociated mechanically and then cultured in proliferation medium with EGF and bFGF. Immunofluorescence method was used to detect the expression of NSCs marker-Nestin within these cells. Cultured in 10% FBS, NSCs began to differentiate. On the onset of the differentiation, HCMV AD169 (MOI=5) was added into the differentiation medium. After 7 days differentiation, the effect of HCMV infection on NSCs differentiation was observed by detecting the rate of nestin, GFAP and HCMV immediate-early (IE) positive cells with confocal microscopy and immunofluorescence method. The resucts showed most of the cells (passage 4-6 ) were Nestin positive and could differentiate into NSE-positive neurons and GFAP-positive astrocytes. On day 7 postinfection, 86% +/- 12% of infected cells were IE positive. The percentage of Nestin-positive cells was 50% +/- 19% and 93% +/- 10% (t= 6.03, P<0.01)and those of GFAP-positive cells was 81% +/- 11% and 55 +/- 17% (t=3.77, P<0.01) in uninfected and infected cells respectively. These findings indicated that NSCs were HCMV permissive cell and HCMV AD 169 infection suppressed the differentiation of Hippocampus-genetic human neural stem cells into astrocytes.
Astrocytes ; cytology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Cytomegalovirus ; growth & development ; physiology ; Epidermal Growth Factor ; pharmacology ; Fibroblast Growth Factor 2 ; pharmacology ; Hippocampus ; cytology ; Humans ; Intermediate Filament Proteins ; metabolism ; Microscopy, Fluorescence ; Multipotent Stem Cells ; cytology ; drug effects ; metabolism ; virology ; Nerve Tissue Proteins ; metabolism ; Nestin ; Neurons ; cytology

OBJECTIVETo investigate the protective effects of selenium on rat hippocampal neurons against ischemia-reperfusion (IR) injury.

METHODSThirty-two rats were randomly divided into sham-operated group, IR group and selenium-treated group, and in the latter two groups, cerebral IR injury was induced by middle cerebral artery occlusion; Na2SeO3 treatment was administer in selenium-treated group. At 14 days after reperfusion, the brain tissues were harvested from the rats and hippocampal neuron injuries were observed by TUNEL and Methylene Blue staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and nerve growth factor (NGF) in the hippocampal tissues were measured by ELISA.

RESULTSCompared with IR group, the rats in selenium-treated group showed no significant increase in the expression of m-NGF (P>0.05), but pro-NGF expression was significantly increased (P<0.05) in the hippocampal tissue. Na2SeO3 treatment significantly inhibited the expressions of TNF-α and IL-1β and decreased the apoptosis of hippocampal neurons following cerebral IR injury (P<0.05).

CONCLUSIONSelenium produces antiapoptotic effect to protect the hippocampal neurons following cerebral IR injury possibly not by increasing the level of m-NGF but by decreasing the expressions of the inflammatory factors.

Animals ; Apoptosis ; Brain Ischemia ; metabolism ; pathology ; Hippocampus ; cytology ; metabolism ; pathology ; Interleukin-1beta ; metabolism ; Male ; Nerve Growth Factor ; metabolism ; Neurons ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; metabolism ; pathology ; Sodium Selenite ; pharmacology ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo investigate the effect of extract of Ginkgo Biloba(EGB) on nerve growth factor(NGF) and Neurotrophin-3(NT-3) expression of hippocampus neurons in streptozotocin-induced type I diabetic rats.

METHODSThirty male SD rats were divided into three groups (n = 10): the control group, diabetic group and EGB-treated group. Strepozotocin were injected intraperitoneally in the later two groups to induce diabetes. EGB-treated group was injected intraperitoneally with EGB, and the same volume of normal saline was injected to the other groups. Concentration of blood glucose and body weight and behaviour were dynamicly monitored. At the end of the 12th week, morphological changes of the hippocampus neurons were observed under microscopy by HE stain. The expression of NGF and NT-3 were assayed by Western blot and RT-PCR respectively.

RESULTSCompared with diabetic group, the behaviour and body weight (P < 0.05) and the concentration of blood glucose (P < 0.05) were significantly improved and the escape latency of Morris water maze test (P < 0.05) was significantly shortened, while the platform searching score was significantly increased (P < 0.01) in EGB treated group; The pathological changes of hippocampus neurons were significantly attenuate by EGB treated; The expression of NGF and NT-3 in hippocampus neurons were significantly increased which assayed by Western blotting and RT-PCR respectively (P < 0.05) in EGB treated group.

CONCLUSIONEGB may improve the learning and memory ability of diabetic rats the mechanism may be attributed to its improvement of the expression of NGF and NT-3 and reducing apoptosis in hippocampus neurons.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; psychology ; Ginkgo biloba ; Hippocampus ; cytology ; Male ; Maze Learning ; drug effects ; Nerve Growth Factor ; metabolism ; Neurons ; drug effects ; metabolism ; Neurotrophin 3 ; metabolism ; Plant Extracts ; pharmacology ; Rats ; Rats, Sprague-Dawley

The intense associative memories that develop between cocaine-paired contexts and rewarding stimuli make addiction hard to cure by contributing to cocaine seeking and relapse. So it's of great importance to examine the neurobiological basis of addiction memory. Cocaine conditioned place preference (CPP) used in this study is a form of Pavlovian conditioning which can establish associations between drug and contextual factors. c-Fos and Zif268 are commonly used immediate early gene (IEG) makers to identify neurons that are activated after a stimulus or behavioral conditioning. This study was designed to reveal neuronal c-Fos, Zif268 expression pattern in 10 brain regions following cocaine context-associated reward memory retrieval in mice, combining animal behavioral study and immunofluorescence method. C57BL/6 mice were randomly divided into 3 groups: Saline retrieval, Cocaine retrieval, and No retrieval of cocaine groups. Cocaine retrieval and No retrieval of cocaine underwent CPP training (one side paired with cocaine, and the other side with saline) except that No retrieval of cocaine group didn't undergo CPP test. Saline retrieval group received saline injections (i.p) on both sides. The results showed that: Neuronal c-Fos, Zif268 protein expression levels in nucleus accumbens (NAc) core both were elevated in Cocaine retrieval group compared with those in Saline retrieval (Control) group during cocaine context-associated reward memory retrieval. Zif268 protein expression level in basolateral amygdala (BLA) was also elevated in Cocaine retrieval group compared with that in control mice. Elevation was not seen in other regions such as hippocampus, prefrontal cortex (PFC). Thus, NAc core and BLA were activated during cocaine context-associated reward memory retrieval. The results suggest that neurons that are activated in NAc core and BLA are crucial basis of cocaine context-associated reward memory.
Animals ; Basolateral Nuclear Complex ; cytology ; Cocaine ; pharmacology ; Conditioning (Psychology) ; Early Growth Response Protein 1 ; metabolism ; Hippocampus ; Memory ; Mice ; Mice, Inbred C57BL ; Neurons ; metabolism ; Nucleus Accumbens ; metabolism ; Prefrontal Cortex ; Proto-Oncogene Proteins c-fos ; metabolism ; Reward

OBJECTIVETo study the protective effects of nerve growth factor (NGF) and Danshen on hippocampal neurons in gerbils (Meriones unguiculatus) with global ischemia-reperfusion injury.

METHODSGlobal ischemia-reperfusion model was established in 54 male Z:ZCLA gerbils by occlusion of the bilateral carotid arteries. The animal models were randomized into 3 groups to receive treatment with normal saline, NGF, and Danshen 30 min after the reperfusion. At 6 h, 3 and 7 days after the reperfusion, the survival of the hippocampal CA1 pyramidal neurons was observed using optical and electron microscopy, and immunohistochemistry was employed to detect the expressions of Bcl-2 and Bax in the neurons.

RESULTSNeuronal apoptosis was not observed in the hippocampus 6 h after the reperfusion, but at 3 and 7 days, the number of apoptotic neurons increased significantly in the CA1 region. Compared with normal saline, treatments with NGF and Danshen both significantly reduced the number of apoptotic neurons at 3 and 7 days. The number of apoptotic neurons showed no significant difference between NGF and Danshen treatment groups at 3 days, but at 7 days, the apoptotic cell number was significantly lower in NGF group (P<0.05). Bcl-2 expression was the highest in NGF group, and its highest expression occurred at 6 h after the reperfusion; Bax expression was detected in saline group, and underwent no significant changes with the passage of time.

CONCLUSIONBoth NGF and Danshen show protective effects against global ischemia-reperfusion injury. NGF has a stronger protective effect than Danshen, and this finding provides experimental evidence for selecting appropriate protective agents in the treatment of ischemic brain damage.

Animals ; Brain Ischemia ; drug therapy ; Drugs, Chinese Herbal ; pharmacology ; Gerbillinae ; Hippocampus ; cytology ; drug effects ; metabolism ; Male ; Nerve Growth Factor ; pharmacology ; Neurons ; drug effects ; Neuroprotective Agents ; pharmacology ; Phenanthrolines ; pharmacology ; Reperfusion Injury ; drug therapy ; Salvia miltiorrhiza

Neurotrophins protect neurons against excitotoxicity; however the signaling mechanisms for this protection remain to be fully elucidated. Here we report that activation of the phosphatidyl inositol 3 kinase (PI3K)/Akt pathway is critical for protection of hippocampal cells from staurosporine (STS) induced apoptosis, characterized by nuclear condensation and activation of the caspase cascade. Both nerve growth factor (NGF) and brain-derived growth factor (BDNF) prevent STS-induced apoptotic morphology and caspase-3 activity by upregulating phosphorylation of the tropomyosin receptor kinase (Trk) receptor. Inhibition of Trk receptor by K252a altered the neuroprotective effect of both NGF and BDNF whereas inhibition of the p75 neurotrophin receptor (p75NTR) had no effect. Impairment of the PI3K/Akt pathway or overexpression of dominant negative (DN)-Akt abolished the protective effect of both neurotrophins, while active Akt prevented cell death. Moreover, knockdown of Akt by si-RNA was able to block the survival effect of both NGF and BDNF. Thus, the survival action of NGF and BDNF against STS-induced neurotoxicity was mediated by the activation of PI3K/Akt signaling through the Trk receptor.
Animals ; Apoptosis/*drug effects ; Brain-Derived Neurotrophic Factor/*metabolism ; Cell Line ; Cell Survival/drug effects ; Cytoprotection/*drug effects ; Gene Knockdown Techniques ; Hippocampus/*cytology ; Nerve Growth Factor/*metabolism ; Neurons/*cytology/drug effects/metabolism ; PC12 Cells ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Receptors, Nerve Growth Factor/metabolism ; Signal Transduction/drug effects ; Staurosporine/*pharmacology

Intermediate filaments, including nestin and glial fibrillary acidic protein (GFAP), are important for the brain to accommodate neural activities and changes during development. The present study examined the temporal changes of nestin and GFAP protein levels in the postnatal development of the mouse hippocampus. Mouse hippocampi were sampled on postnatal day (PND) 1, 3, 6, 18, and 48. Western blot analysis showed that nestin expression was high at PND 1 and markedly decreased until PND 18. Conversely, GFAP expression was acutely increased in the early phase of postnatal development. Nestin immunoreactivity was localized mainly in the processes of ramified cells at PND 1, but expression subsequently decreased. In contrast, GFAP was evident mainly in the marginal cells of the hippocampus at PND 1, but immunoreactivity revealed satellite, radial, or ramified shapes of the cells from PND 6-48. This study demonstrates that the opposing pattern of nestin and GFAP expressions in mouse hippocampus during postnatal development occur in the early development stage (PND 1-18), suggesting that the opposing change of nestin and GFAP in early postnatal development is important for neural differentiation and positioning in the mouse hippocampus.
*Aging ; Animals ; Blotting, Western ; Brain/cytology/growth & development ; Female ; *Gene Expression Regulation, Developmental ; Glial Fibrillary Acidic Protein/genetics/*metabolism ; Hippocampus/cytology/*growth & development/*metabolism ; Immunohistochemistry ; Intermediate Filament Proteins/genetics/*metabolism ; Male ; Mice ; Mice, Inbred ICR ; Nerve Tissue Proteins/genetics/*metabolism ; Neurons/metabolism

New-born cells continue to proliferate and survive to become mature granule cells in adult rat hippocampus. Although this process, known as neurogenesis, is inhibited by acute stress, it is not clear whether chronic stress affects neurogenesis. To determine whether chronic mild stress (CMS) influences neurogenesis in the adult rat hippocampus, male Sprague-Dawley rats were exposed to CMS and administered bromodeoxyuridine (BrdU) before or after CMS to observe the survival/differentiation or proliferation of new-born cells, respectively. In addition, we measured brain-derived neurotrophic factor (BDNF) mRNA in the granule cell layer (GCL) of the hippocampus, because BDNF is known to play an important role in the survival of new-born cells. CMS significantly decreased the survival of newborn cells in the GCL, but did not influence the proliferation or differentiation of new-born cells. CMS did not affect the proliferation and survival of new-born cells in the hilus. In addition, CMS did not change BDNF mRNA levels in the GCL. These results demonstrate that CMS reduces the survival of new-born cells but not of their proliferation, suggesting that repeated mild stress could influence a part of neurogenesis, but not the whole part of neurogenesis. These results raise the possibility that the survival of new-born cells may be suppressed in the presence of normal BDNF mRNA levels in GCL.
Animals ; Brain-Derived Neurotrophic Factor/metabolism ; Bromodeoxyuridine/*administration & dosage ; Calcium-Binding Protein, Vitamin D-Dependent/metabolism ; Cell Proliferation ; Cell Survival ; Comparative Study ; Fluorescein-5-isothiocyanate ; Fluorescent Antibody Technique, Indirect ; Fluorescent Dyes ; Glial Fibrillary Acidic Protein/metabolism ; Hippocampus/cytology/growth & development/*pathology ; Immunohistochemistry ; In Situ Hybridization ; Male ; Microscopy, Confocal ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Restraint, Physical ; Rhodamines ; Stress/pathology/*physiopathology