Animals ; Apoptosis ; Cognition ; Diabetes Mellitus, Experimental/drug therapy* ; Drugs, Chinese Herbal/pharmacology* ; Hippocampus/cytology* ; Moringa/chemistry* ; Neurons/drug effects* ; Plant Leaves/chemistry* ; Rats ; Rats, Sprague-Dawley

In this study, we improved the culture method of mouse hippocampal primary microglia to obtain hippocampal ramified microglia with high activity and purity, which were resemble to the resting status of normal microglia in healthy brain in vivo. Hippocampal tissue was excised from 2-4-week-old SPF C57BL/6J mice and cut into pieces after PBS perfusion, and then manually dissociated into the single-cell suspension by using Miltenyi Biotec's Adult Brain Dissociation Kit. The tissue fragments such as myelin in the supernatant were removed by debris removal solution in the kit. The cell suspension was incubated with CD11b immunomagnetic beads for 15 min at 4 °C. To obtain high-purity microglia, we used two consecutive cell-sorting steps by magnetic activated cell sorting (MACS). After centrifugation, the cells were resuspended and seeded in a 24-well culture plate. The primary microglia were cultured with complete medium (CM) or TIC medium (a serum-free medium with TGF-β, IL-34 and cholesterol as the main nutritional components) for 4 days, and then were used for further experiments. The results showed that: (1) The cell viability was (56.03 ± 2.10)% by manual dissociation of hippocampus; (2) Compared with immunopanning, two-step MACS sorting allowed for efficient enrichment of microglia with higher purity of (86.20 ± 0.68)%; (3) After being incubated in TIC medium for 4 d, microglia exhibited branching, quiescent morphology; (4) The results from qRT-PCR assay showed that the levels of TNF-α, IL-1β and CCL2 mRNA in TIC cultured-microglia were similar to freshly isolated microglia, while those were much higher in CM cultured-microglia after incubation for 4 d and 7 d (P < 0.05). Taken together, compared to the conventional approaches, this modified protocol of mouse hippocampal primary microglia culture by using MACS and TIC medium enables the increased yield and purity of microglia in the quiescent state, which is similar to normal ramified microglia in healthy brain in vivo.
Animals ; Cell Culture Techniques ; methods ; Cell Separation ; methods ; Cells, Cultured ; Hippocampus ; Magnetics ; Mice ; Mice, Inbred C57BL ; Microglia ; cytology

The complex spatial and temporal organization of neural activity in the brain is important for information-processing that guides behavior. Hence, revealing the real-time neural dynamics in freely-moving animals is fundamental to elucidating brain function. Miniature fluorescence microscopes have been developed to fulfil this requirement. With the help of GRadient INdex (GRIN) lenses that relay optical images from deep brain regions to the surface, investigators can visualize neural activity during behavioral tasks in freely-moving animals. However, the application of GRIN lenses to deep brain imaging is severely limited by their availability. Here, we describe a protocol for GRIN lens coating that ensures successful long-term intravital imaging with commercially-available GRIN lenses.
Animals ; Biocompatible Materials ; Brain ; physiology ; Hippocampus ; cytology ; Lenses ; Mice, Inbred C57BL ; Mice, Transgenic ; Microscopy, Fluorescence ; methods ; Neuroimaging ; instrumentation ; methods ; Neurons ; physiology

OBJECTIVE: To observe the expressions of sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate receptor 2 (S1PR2) in hippocampus of epileptic rats and to investigate the pathogenesis of SphK1 and S1PR2 in epilepsy. METHODS: One hundred and eight male Sprague-Dawley (SD) rats were randomly divided into control group (n=48) and pilocarpine (PILO) group (n=60). A robust convulsive status epilepticus (SE) was induced in PILO group rats by the application of pilocarpine. Control group rats were injected with respective of physiological saline. Pilocarpine group was randomly divided into 6 subgroups (n=8): acute group (E6 h, E1 d, E3 d), latent group (E7 d) and chronic group (E30 d, E56 d). Each subgroup has 8 control rats and 8 epileptic rats. Hippocampal tissue and brain slices were obtained from control rats and rats subjected to the Li-PILO model of epilepsy at 6 h, 1 d, 3 d,7 d,30 d and 56 d after status epilepticus (SE). Western blot technique was used to determine the expressions of SphK1 and S1PR2 in hippocampus at different point of time after pilocarpine treatment. Immunofluorescence was applied to detect the activation and proliferation of hippocampal astrocytes and the localization of SphK1 and S1PR2 in rat hippocampal astrocytes. RESULTS: Compared with control group, the levels of SphK1 in acute phase (E3 d), latent phase (E7 d) and chronic phase (E30 d, E56 d) were significantly increased while the expressions of S1PR2 were decreased in acute phase (E3 d), latent phase (E7 d) and chronic phase (E30 d, E56 d)(P＜0.05 or P＜0.01). Immunofluorescence results showed astrocyte activation and proliferation in hippocampus of epileptic (E7 d) rats (P＜0.05). Confocal microscopy confirmed the preferential expressions of SphK1 and S1PR2 in epileptic rat(E7 d)hippocampal astrocytes. CONCLUSION The results indicate that SphK1 and S1PR2 may play an important role in the pathogenesis of epilepsy by regulating the activation and proliferation of hippocampal astrocytes and altering neuronal excitability.
Animals ; Astrocytes ; enzymology ; Epilepsy ; enzymology ; physiopathology ; Hippocampus ; cytology ; enzymology ; Male ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; Pilocarpine ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Lysosphingolipid ; metabolism

The present study was aimed to investigate the effects and mechanisms of electro-acupuncture (EA) on proliferation and differentiation of neural stem cells in the hippocampus of C57 mice exposed to different doses of X-ray radiation. Thirty-day-old C57BL/6J mice were randomly divided into control, irradiation, and EA groups. The control group was not treated with irradiation. The irradiation groups were exposed to different doses of X-ray (4, 8 or 16 Gy) for 10 min. The EA groups were electro-acupunctured at Baihui, Fengfu and bilateral Shenyu for 3 courses of treatment after X-ray radiation. Immunohistochemistry was used to evaluate proliferation and differentiation of the hippocampal neural stem cell. RT-PCR and Western blot were used to detect mRNA and protein expressions of Notch1 and Mash1 in the hippocampus, respectively. The results showed that, compared with the control group, the numbers of BrdU positive cells (4, 8 Gy subgroup) and BrdU/NeuN double-labeling positive cells (3 dose subgroups) were decreased significantly in the irradiation group, but the above changes could be reversed by EA. Compared with the control group, the number of BrdU/GFAP double-labeling positive cells in each dose subgroup of irradiation group was decreased significantly, while EA could reverse the change of 4 and 8 Gy dose subgroups. In addition, compared with the control group, the expression levels of Notch1 mRNA and protein in hippocampus were up-regulated, and the expression levels of Mash1 mRNA and protein were significantly decreased in each dose subgroup of irradiation group. Compared with irradiation group, the expression levels of Notch1 mRNA and protein in hippocampus of EA group were decreased significantly in each dose subgroup, and the expression levels of Mash1 mRNA and protein were increased significantly in 4 and 8 Gy subgroups. These results suggest that irradiation affects the proliferation and differentiation of neural stem cells in hippocampus of mice, whereas EA may significantly increase the proliferation and differentiation of hippocampal neural stem cells via the regulation of Notch signaling pathway.
Animals ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Cell Differentiation ; Cell Proliferation ; Electroacupuncture ; Hippocampus ; cytology ; radiation effects ; Mice, Inbred C57BL ; Neural Stem Cells ; cytology ; radiation effects ; Random Allocation ; Receptor, Notch1 ; metabolism ; X-Rays ; adverse effects

It was reported that α7 nicotinic acetylcholine receptor (α7-nAChR) knockout (α7 KO) mice showed few functional phenotypes. The purpose of this study was to investigate the effect of α7 KO on the electrophysiological characteristics of hippocampus in mice. The effect of α7 KO on hippocampal CA3-CA1 synaptic transmission in mice was evaluated by standard extracellular field potential recordings. The electrophysiological phenotype of γ-aminobutyrate A receptors (GABA-Rs) of single hippocampal neuron was detected by perforated patch-clamp recordings. The results showed that, the slope of field excitatory postsynaptic potential (fEPSP) and carbachol-induced theta oscillation were significantly decreased in the hippocampal CA1 neurons of α7 KO mice, compared with those of wild type mice. Under the treatment of GABA-R agonist muscimol, the I-V curves of both the hippocampal CA1 and CA3 neurons of α7 KO mice shifted towards depolarizing direction obviously, compared with those of wild type mice. These results suggest that the hippocampal CA3-CA1 synaptic transmission in α7 KO mice was significantly impaired and GABA-R maturation was significantly delayed, indicating that the deletion of α7-nAChR gene could significantly change the electrophysiological function of the hippocampus. The results may provide a new understanding of the role of α7-nAChR in hippocampal function and associated diseases.
Animals ; Hippocampus ; cytology ; Mice ; Mice, Knockout ; Neurons ; physiology ; Phenotype ; Synaptic Transmission ; alpha7 Nicotinic Acetylcholine Receptor ; physiology

BackgroundGlehnia littoralis has been used for traditional Asian medicine, which has diverse therapeutic activities. However, studies regarding neurogenic effects of G. littoralis have not yet been considered. Therefore, in this study, we examined effects of G. littoralis extract on cell proliferation, neuroblast differentiation, and the maturation of newborn neurons in the hippocampus of adult mice.

MethodsA total of 39 male ICR mice (12 weeks old) were randomly assigned to vehicle-treated and 100 and 200 mg/kg G. littoralis extract-treated groups (n = 13 in each group). Vehicle and G. littoralis extract were orally administrated for 28 days. To examine neurogenic effects of G. littoralis extract, we performed immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU, an indicator for cell proliferation) and doublecortin (DCX, an immature neuronal marker) and double immunofluorescence staining for BrdU and neuronal nuclear antigen (NeuN, a mature neuronal marker). In addition, we examined expressional changes of brain-derived neurotrophic factor (BDNF) and its major receptor tropomyosin-related kinase B (TrkB) using Western blotting analysis.

ResultsTreatment with 200 mg/kg, not 100 mg/kg, significantly increased number of BrdU-immunoreactive () and DCX cells (48.0 ± 3.1 and 72.0 ± 3.8 cells/section, respectively) in the subgranular zone (SGZ) of the dentate gyrus (DG) and BrdU/NeuN cells (17.0 ± 1.5 cells/section) in the granule cell layer as well as in the SGZ. In addition, protein levels of BDNF and TrkB (about 232% and 244% of the vehicle-treated group, respectively) were significantly increased in the DG of the mice treated with 200 mg/kg of G. littoralis extract.

ConclusionG. littoralis extract promots cell proliferation, neuroblast differentiation, and neuronal maturation in the hippocampal DG, and neurogenic effects might be closely related to increases of BDNF and TrkB proteins by G. littoralis extract treatment.

Animals ; Apiaceae ; chemistry ; Blotting, Western ; Brain-Derived Neurotrophic Factor ; metabolism ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Dentate Gyrus ; cytology ; drug effects ; Hippocampus ; cytology ; drug effects ; Immunohistochemistry ; Male ; Mice ; Microtubule-Associated Proteins ; metabolism ; Neurogenesis ; drug effects ; Neuropeptides ; metabolism ; Plant Extracts ; pharmacology ; Receptor, trkB ; metabolism

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.
Animals ; Animals, Newborn ; Biomarkers ; metabolism ; Cell Proliferation ; genetics ; Cyclin-Dependent Kinase 2 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p57 ; genetics ; metabolism ; Cyclins ; genetics ; metabolism ; Gene Expression Regulation ; Hippocampus ; cytology ; metabolism ; Ki-67 Antigen ; genetics ; metabolism ; Magnetic Fields ; MicroRNAs ; genetics ; metabolism ; Neural Stem Cells ; cytology ; metabolism ; Primary Cell Culture ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

The possible role of minocycline in microglial activation and neuronal death after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in mice was investigated in this study. The mice were given potassium chloride to stop the heart beating for 8 min to achieve CA, and they were subsequently resuscitated with epinephrine and chest compressions. Forty adult C57BL/6 male mice were divided into 4 groups (n=10 each): sham-operated group, CA/CPR group, CA/CPR+minocycline group, and CA/CPR+vehicle group. Animals in the latter two groups were intraperitoneally injected with minocycline (50 mg/kg) or vehicle (normal saline) 30 min after recovery of spontaneous circulation (ROSC). Twenty-four h after CA/CPR, the brains were removed for histological evaluation of the hippocampus. Microglial activation was evaluated by detecting the expression of ionized calcium-binding adapter molecule-1 (Iba1) by immunohistochemistry. Neuronal death was analyzed by hematoxylin and eosin (H&E) staining and the levels of tumor necrosis factor-alpha (TNF-α) in the hippocampus were measured by enzyme-linked immunosorbent assay (ELISA). The results showed that the neuronal death was aggravated, most microglia were activated and TNF-α levels were enhanced in the hippocampus CA1 region of mice subjected to CA/CPR as compared with those in the sham-operated group (P<0.05). Administration with minocycline 30 min after ROSC could significantly decrease the microglial response, TNF-α levels and neuronal death (P<0.05). It was concluded that early administration with minocycline has a strong therapeutic potential for CA/CPR-induced brain injury.
Animals ; Cardiopulmonary Resuscitation ; Cell Death ; drug effects ; Enzyme-Linked Immunosorbent Assay ; Heart Arrest ; pathology ; Hippocampus ; cytology ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Microglia ; cytology ; drug effects ; Minocycline ; pharmacology ; Neurons ; drug effects ; Tumor Necrosis Factor-alpha ; metabolism

This study aims to construct the recombinant lentivirus vector containing specific small interfering RNA (siRNA) targeting rat CREB binding protein(CBP)gene and to identify its function of inhibiting the expressions of acetylated histone in primarily cultured hippocampal neurons. Firstly, we constructed four kinds of recombinant lentivirus siCBP. And then we used them to infect the primarily cultured hippocampal neurons, and performed real-time PCR, western blot respectively to detect the expressions of CBP. Afterwards, the most effective lentivirus siCBP was used to infect the primarily cultured hippocampal neurons, and then the HAT activity and protein expressions of acetylated histone Ac-H3, Ac-H4 of the neurons were examined. By using PCR, endonuclease cutting and gene sequencing, we confirmed that the target genes were correctly cloned in lentivirus vector. Besides, CBP mRNA and protein expressions in neurons were found to be with varying degrees of decreases after infections of the four kinds of lentivirus siCBP. Furthermore, the representative and most effective lentivirus GR806 could effectively inhibit the HAT activity and the protein expressions of Ac-H3, Ac-H4 in neurons. It provides the experimental basis for the subsequent application of siCBP to clarify the effects and corresponding molecular mechanism of the CBP-dependent histone acetylation on learning and memory function in hippocampus.
Acetylation ; Animals ; CREB-Binding Protein ; metabolism ; Genetic Vectors ; Hippocampus ; cytology ; Histones ; metabolism ; Lentivirus ; Memory ; Neurons ; metabolism ; Primary Cell Culture ; RNA, Messenger ; RNA, Small Interfering ; Rats ; Real-Time Polymerase Chain Reaction