Gonadotropin-releasing hormone (GnRH) neurons in the preoptic area may undergo mor-phological changes during the pubertal period when their activities are upregulated. To clarify the regulatory mechanism of puberty onset, this study aimed to investigate the morphological changes of GnRH neurons in the preoptic area of GnRH-enhanced green lfuorescent protein transgenic rats. Under confocal laser microscopy, pubertal GnRH neurons exhibited an inverted Y distribution pattern. Prepubertal GnRH neurons were generally unipolar and bipolar, and were distinguished as smooth type cells with few small processes or irregular type cells with many spine-like processes in the proximal dendrites. The number of GnRH neurons in the preoptic area and spine-like processes were increased during the course of reproductive matu-ration. There was no signiifcant difference between male and female rats. Immunolfuorescence staining revealed synaptophysin punctae close to the distal end of GnRH neurons, indicating that some presynaptic terminals may form a synaptic linkage with these neurons.

Alzheimer’s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeifciency to establish an animal model of Alzhei-mer’s disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was signiifcantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines (interleukin-2, interferon-γ) and hippocampal microglia-related cyto-kines (interleukin-1β, tumor necrosis factor-α) correlated with the number of regenerated neural progenitor cells in the hippocampus. hTese results indicate that T cells promote hippocampal neurogenesis in Alzheimer’s disease and T-cell immunodeifciency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer’s disease mice. Our ifndings provide an experimental basis for understanding the role of T cells in Alzheimer’s disease.

Previous studies have demonstrated that doublecortin-positive immature neurons exist pre-dominantly in the superficial layer of the cerebral cortex of adult mammals such as guinea pigs, and these neurons exhibit very weak properties of self-proliferation during adulthood under physiological conditions. To verify whether environmental enrichment has an impact on the proliferation and maturation of these immature neurons in the prefrontal cortex of adult guinea pigs, healthy adult guinea pigs were subjected to short-term environmental enrichment. Animals were allowed to play with various cognitive and physical stimulating objects over a period of 2 weeks, twice per day, for 60 minutes each. Immunolfuorescence staining results indicated that the number of doublecortin-positive cells in layer II of the prefrontal cortex was signiifcantly increased after short-term environmental enrichment exposure. In addition, these doublecortin-positive cells co-expressed 5-bromo-2-deoxyuridine (a marker of cell prolifera-tion), c-Fos (a marker of cell viability) and NeuN (a marker of mature neurons). Experimental ifndings showed that short-term environmental enrichment can induce proliferation, activation and maturation of doublecortin-positive cells in layer II of the prefrontal cortex of adult guinea pigs.

Edaravone has been shown to reduce ischemia/reperfusion-induced peripheral nerve injury. However, the therapeutic effect of edaravone on peripheral nerve injury caused by mechanical factors is unknown. In the present study, we established a peripheral nerve injury model by crushing the sciatic nerve using hemostatic forceps, and then administered edaravone 3 mg/kg intraperitoneally. The sciatic functional index and superoxide dismutase activity of the sciatic nerve were increased, and the malondialdehyde level was decreased in animals in the edaravone group compared with those in the model group. Bcl-2 expression was increased, but Bax expres-sion was decreased in anterior horn cells of the L4-6 spinal cord segments. These results indicated that edaravone has a neuroprotective effect following peripheral nerve injury caused by mechan-ical factors through alleviating free radical damage to cells and inhibiting lipid peroxidation, as well as regulating apoptosis-related protein expression.

3β-Hydroxysteroid-Δ24 reductase (DHCR24) is a multifunctional enzyme that localizes to the endoplasmic reticulum and has neuroprotective and cholesterol-synthesizing activities. DHCR24 overexpression confers neuroprotection against apoptosis caused by amyloidβdeposition. hTe present study aimed to construct two recombinant adenoviruses driving DHCR24 expression specifically in neurons. Two SYN1 promoter DNA fragments were obtained from human (h) and rat (r). Recombinant Ad-r(h)SYN1-DHCR24 was transfected into AD-293, N2A (mouse neuroblastoma), and MIN6 (mouse pancreatic carcinoma) cells. Western blot analysis showed DHCR24 was specially expressed in 293 and N2A cells, but no speciifc band was found in MIN6 cells. hTis demonstrates that the recombinant adenoviruses successfully express DHCR24, and no expression is observed in non-neuronal cells. TUNEL assay results showed apoptosis was inhibited in adenovirus-transfected neurons. Detecting reactive oxygen species by immunolfu-orescence, we found that adenovirus transfection inhibits apoptosis through scavenging excess reactive oxygen species. Our ifndings show that the recombinant DHCR24 adenoviruses induce neuron-specific DHCR24 expression, and thereby lay the foundation for further studies on DHCR24 gene therapy for Alzheimer’s disease.

We used animal models of“forced swim stress”and“chronic unpredictable stress”, and tried to reveal whether a passive coping style of high lfotation behavior in forced swim stress predicts an-hedonia behavior after chronic unpredictable stress, and whether the dopamine system regulates lfoating and anhedonia behaviors. Our results conifrmed that depression-prone rats use“lfoating behavior”as a coping strategy in forced swim stress and more readily suffer from anhedonia during chronic unpredictable stress. Intraperitoneal injection or nucleus accumbens microin-jection of the dopamine 2/3 receptor subtype agonist ropinirole reduced lfoating behaviors in depression-prone animals, but increased sucrose preference in rats showing anhedonia. These data indicate that lfoating behavior is a defensive mode that is preferred by susceptible individ-uals under conditions of acute stress. Simultaneously, these animals more readily experienced anhedonia under long-term stress;that is, they were more readily affected by depression. Our results suggest that dopamine 2/3 receptor subtypes in the nucleus accumbens play an important role in lfoating behaviors and anhedonia.

Carbon nanotubes can carry protein into cells to induce biological effects. Amino-functionalized carbon nanotubes are soluble and biocompatible, have high reactivity and low toxicity, and can help promote nerve cell growth. In this study, amino-functionalized ethylenediamine-treated multi-walled carbon nanotubes were used to prepare carbon nanotubes-nerve growth factor complexes by non-covalent grafting. The physicochemical properties, cytotoxicity to PC12 and chick embryo dorsal root ganglion, and biological activity of the carbon nanotubes-nerve growth factor complexes were investigated. The results showed that amino functionalization improved carbon nanotubes-nerve growth factor complex dispersibility, reduced their toxicity to PC12 cells, and promoted PC12 cell differentiation and chick embryo dorsal root ganglion.

The distance between the two electrode tips can greatly inlfuence the parameters used for record-ing compound nerve action potentials. To investigate the optimal parameters for these recordings in the rat median nerve, we dissociated the nerve using different methods and compound nerve action potentials were orthodromically or antidromically recorded with different electrode spac-ings. Compound nerve action potentials could be consistently recorded using a method in which the middle part of the median nerve was intact, with both ends dissociated from the surrounding fascia and a ground wire inserted into the muscle close to the intact part. When the distance be-tween two stimulating electrode tips was increased, the threshold and supramaximal stimulating intensity of compound nerve action potentials were gradually decreased, but the amplitude was not changed signiifcantly. When the distance between two recording electrode tips was increased, the amplitude was gradually increased, but the threshold and supramaximal stimulating intensity exhibited no signiifcant change. Different distances between recording and stimulating sites did not produce signiifcant effects on the aforementioned parameters. A distance of 5 mm between recording and stimulating electrodes and a distance of 10 mm between recording and stimulating sites were found to be optimal for compound nerve action potential recording in the rat median nerve. In addition, the orthodromic compound action potential, with a biphasic waveform that was more stable and displayed less interference (however also required a higher threshold and higher supramaximal stimulus), was found to be superior to the antidromic compound action potential.

Oligodendrocyte lineage gene 1 plays a key role in hypoxic-ischemic brain damage and myelin repair. miRNA-9 is involved in the occurrence of many related neurological disorders. Bioin-formatics analysis demonstrated that miRNA-9 complementarily, but incompletely, bound oligodendrocyte lineage gene 1, but whether miRNA-9 regulates oligodendrocyte lineage gene 1 remains poorly understood. Whole brain slices of 3-day-old Sprague-Dawley rats were cultured and divided into four groups:control group;oxygen-glucose deprivation group (treatment with 8% O2+ 92%N2 and sugar-free medium for 60 minutes);transfection control group (after oxygen and glucose deprivation for 60 minutes, transfected with control plasmid) and miRNA-9 transfection group (after oxygen and glucose deprivation for 60 minutes, transfected with miRNA-9 plasmid). From the third day of transfection, and with increasing culture days, oligodendrocyte lineage gene 1 expression increased in each group, peaked at 14 days, and then decreased at 21 days. Real-time quantitative PCR results, however, demonstrated that oligoden-drocyte lineage gene 1 expression was lower in the miRNA-9 transfection group than that in the transfection control group at 1, 3, 7, 14, 21 and 28 days after transfection. Results suggested that miRNA-9 possibly negatively regulated oligodendrocyte lineage gene 1 in brain tissues during hypoxic-ischemic brain damage.

The murine microglial cell line BV2 has neuroprotective effects, but is toxic to neurons by secret-ing inlfammatory cytokines, and is an important target in the treatment of nerve inlfammation and neurodegenerative diseases. In the present study, we observed the effects of transfecting three amyloid precursor-like protein 2 (APLP2) C-terminal fragments (CTFs; C57, C50 and C31) in the pEGFP-N1 vector on S100A9 expression in BV2 cells. Reverse transcription-PCR, western blot assay and immunocytochemistry revealed that S100A9 protein and mRNA expression was greater in BV2 cells after CTF transfection than after mock transfection with an empty vector. Furthermore, transfection of full-length APLP2-751 resulted in low levels of S100A9 protein ex-pression. Our results show that APLP2-CTFs upregulate S100A9 protein and mRNA expression in BV2 cells, and identify a novel pathway involved in neuronal injury and apoptosis, and repair and protection in Alzheimer’s disease.

Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxel-based morphometry have been conducted, with inconsistent results. We detected subtle changes in the brain structure of 23 cases of type 2 diabetes mellitus, and demonstrated that there was no signiifcant difference between the total volume of gray and white matter of the brain of type 2 diabetes mellitus patients and that in controls. Regional atrophy of gray matter mainly occurred in the right temporal and left occipital cortex, while regional atrophy of white matter involved the right temporal lobe and the right cerebellar hemisphere. The ankle-brachial index in patients with type 2 diabetes mellitus strongly correlated with the volume of brain regions in the default mode network. The ankle-brachial index, followed by the level of glycosylated hemoglobin, most strongly correlated with the volume of gray matter in the right temporal lobe. These data suggest that voxel-based morphometry could detect small structural changes in patients with type 2 diabetes mellitus. Early macrovascular atherosclerosis may play a crucial role in subtle brain atro-phy in type 2 diabetes mellitus patients, with chronic hyperglycemia playing a lesser role.

The increase in neurotrophic factors after craniocerebral injury has been shown to promote fracture healing. Moreover, neurotrophic factors play a key role in the regeneration and repair of peripheral nerve. However, whether craniocerebral injury alters the repair of peripheral nerve injuries remains poorly understood. Rat injury models were established by transecting the left sciatic nerve and using a free-fall device to induce craniocerebral injury. Compared with sciat-ic nerve injury alone after 6-12 weeks, rats with combined sciatic and craniocerebral injuries showed decreased sciatic functional index, increased recovery of gastrocnemius muscle wet weight, recovery of sciatic nerve ganglia and corresponding spinal cord segment neuron mor-phologies, and increased numbers of horseradish peroxidase-labeled cells. These results indicate that craniocerebral injury promotes the repair of peripheral nerve injury.

Previous studies show that chronic acrylamide exposure leads to central and peripheral neu-ropathy. However, the underlying mechanisms remained unclear. In this study, we examined the permeability of the blood-cerebrospinal lfuid barrier, and its ability to secrete transthyretin and transport leptin of rats exposed to acrylamide for 7, 14, 21 or 28 days. Transthyretin levels in cerebrospinal lfuid began to decline on day 7 after acrylamide exposure. The sodium lfuorescein level in cerebrospinal lfuid was increased on day 14 after exposure. Evans blue concentration in cerebrospinal lfuid was increased and the cerebrospinal lfuid/serum leptin ratio was decreased on days 21 and 28 after exposure. In comparison, the cerebrospinal lfuid/serum albumin ratio was increased on day 28 after exposure. Our ifndings show that acrylamide exposure damages the blood-cerebrospinal lfuid barrier and impairs secretory and transport functions. These changes may underlie acrylamide-induced neurotoxicity.

The precedence effect is a prerequisite for faithful sound localization in a complex auditory envi-ronment, and is a physiological phenomenon in which the auditory system selectively suppresses the directional information from echoes. Here we investigated how neurons in the inferior col-liculus respond to the paired sounds that produce precedence-effect illusions, and whether their ifring behavior can be modulated through inhibition with gamma-aminobutyric acid (GABA). We recorded extracellularly from 36 neurons in rat inferior colliculus under three conditions:no injection, injection with saline, and injection with gamma-aminobutyric acid. The paired sounds that produced precedence effects were two identical 4-ms noise bursts, which were deliv-ered contralaterally or ipsilaterally to the recording site. The normalized neural responses were measured as a function of different inter-stimulus delays and half-maximal interstimulus delays were acquired. Neuronal responses to the lagging sounds were weak when the inter-stimulus delay was short, but increased gradually as the delay was lengthened. Saline injection produced no changes in neural responses, but after local gamma-aminobutyric acid application, responses to the lagging stimulus were suppressed. Application of gamma-aminobutyric acid affected the normalized response to lagging sounds, independently of whether they or the paired sounds were contralateral or ipsilateral to the recording site. These observations suggest that local inhibition by gamma-aminobutyric acid in the rat inferior colliculus shapes the neural responses to lagging sounds, and modulates the precedence effect.

Drugs can cause obvious damage to the brain. To verify the relationship between acupuncture, neurotrophic factor expression and brain cell structural changes, this study established a rat model of heroin relapse using intramuscular injection of increasing amounts of heroin. During the detoxiifcation period, rat models received acupuncture at Baihui (DU20) and Dazhui (DU14). Electron microscopy demonstrated that the structure of the ventral tegmental area in heroin relapse rats gradually became normalized after acupuncture treatment. Immunohistochem-ical staining exhibited that the expression of brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor increased in the ventral tegmental area following acupuncture. Moreover, the effects were similar to that of methadone, a type of medicine called an opioid. Results suggested that acupuncture at Baihui and Dazhui protected brain neurons against injury in rats with heroin relapse by promoting brain-derived neurotrophic factor and glial cell line-de-rived neurotrophic factor expression.

Previous studies have shown that baicalin prevented iron accumulation after substantia nigra injury, reduced divalent metal transporter 1 expression, and increased ferroportin 1 expression in the substantia nigra of rotenone-induced Parkinson’s disease rats. In the current study, we investigated the relationship between iron accumulation and transferrin expression in C6 cells, to explore the mechanisms of the inhibitory effect of baicalin on iron accumulation observed in Parkinson’s disease rats. Iron content was detected using inductively coupled plasma-atomic emission spectroscopy. Results showed that iron content decreased 41%after blocking divalent metal transporter 1 and ferroportin 1 proteins. After treatment with ferric ammonium citrate of differing concentrations (10, 50, 100, 400 μg/mL) in C6 glioma cells, cell survival rate and ferroportin 1 expression were negatively correlated with ferric ammonium citrate concentration, but divalent metal transporter 1 expression positively correlated with ferric ammonium citrate concentration. Baicalin or deferoxamine reduced divalent metal transporter 1 expression, but increased ferroportin 1 expression in the 100 μg/mL ferric ammonium citrate-loaded C6 cells. These results indicate that baicalin down-regulated iron concentration, which positively regulat-ed divalent metal transporter 1 expression and negatively regulated ferroportin 1 expression, and decreased iron accumulation in the substantia nigra.

After hypoxia, ischemia, or inlfammatory injuries to the central nervous system, the damaged cells release a large amount of adenosine triphosphate, which may cause secondary neuronal death. Autophagy is a form of cell death that also has neuroprotective effects. Cell Counting Kit assay, monodansylcadaverine staining, lfow cytometry, western blotting, and real-time PCR were used to determine the effects of exogenous adenosine triphosphate treatment at different concentrations (2, 4, 6, 8, 10 mmol/L) over time (1, 2, 3, and 6 hours) on the apoptosis and autophagy of SH-SY5Y cells. High concentrations of extracellular adenosine triphosphate induced autophagy and apoptosis of SH-SY5Y cells. The enhanced autophagy ifrst appeared, and peaked at 1 hour after treatment with adenosine triphosphate. Cell apoptosis peaked at 3 hours, and persisted through 6 hours. With prolonged exposure to the adenosine triphosphate treatment, the fraction of apoptotic cells increased. These data suggest that the SH-SY5Y neural cells initiated autophagy against apoptosis within an hour of adenosine triphosphate treatment to protect themselves against injury.

It is difficult to control the degree of ischemic postconditioning in the brain and other isch-emia-sensitive organs. Remote ischemic postconditioning could protect some ischemia-sensitive organs through measures on terminal organs. In this study, a focal cerebral ischemia-reperfusion injury model was established using three cycles of remote ischemic postconditioning, each cycle consisted of 10-minute occlusion of the femoral artery and 10-minute opening. The results showed that, remote ischemic postconditioning signiifcantly decreased the percentage of the in-farct area and attenuated brain edema. In addition, inlfammatory nuclear factor-κB expression was signiifcantly lower, while anti-apoptotic Bcl-2 expression was signiifcantly elevated in the ce-rebral cortex on the ischemic side. Our ifndings indicate that remote ischemic postconditioning attenuates focal cerebral ischemia/reperfusion injury, and that the neuroprotective mechanism is mediated by an anti-apoptotic effect and reduction of the inlfammatory response.

Tooth loss has been shown to affect learning and memory in mice and increases the risk of Alz-heimer’s disease. The dentate gyrus is strongly associated with cognitive function. This study hypothesized that tooth loss affects neurons in the dentate gyrus. Adult male mice were random-ly assigned to either the tooth loss group or normal control group. In the tooth loss group, the left maxillary and mandibular molars were extracted. Normal control mice did not receive any intervention. Immunolfuorescence staining revealed that the density and absorbance of double-cortin-and neuronal nuclear antigen-positive cells were lower in the tooth loss group than in the normal control group. These data suggest that tooth loss may inhibit neurogenesis in the dentate gyrus of adult mice.

CD93 and GAIP-interacting protein, C termius (GIPC) have been shown to interactively alter phagocytic processes of immune cells. CD93 and GIPC expression and localization during cen-tral nervous system inflammation have not yet been reported. In this study, we established a rat model of brain inlfammation by lipopolysaccharide injection to the lateral ventricle. In the brain of rats with inlfammation, western blots showed increased CD93 expression that decreased over time. GIPC expression was unaltered. Immunohistochemistry demonstrated extensive distribution of CD93 expression mainly in cell membranes in the cerebral cortex. After lipopoly-saccharide stimulation, CD93 expression increased and then reduced, with distinct staining in the cytoplasm and nucleus. Double immunolfuorescence staining in cerebral cortex of normal rats showed that CD93 and GIPC widely expressed in resting microglia and neurons. CD93 was mainly expressed in microglial and neuronal cell membranes, while GIPC was expressed in both cell membrane and cytoplasm. In the cerebral cortex at 9 hours after model establishment, CD93-immunoreactive signal diminished in microglial membrane, with cytoplasmic transloca-tion and aggregation detected. GIPC localization was unaltered in neurons and microglia. These results are the ifrst to demonstrate CD93 participation in pathophysiological processes of central nervous system inlfammation.