Occupational exposure to 1-bromopropane (1-BP) induces learning and memory deficits. However, no therapeutic strategies are currently available. Accumulating evidence has suggested that N-methyl-D-aspartate receptors (NMDARs) and neuroinflammation are involved in the cognitive impairments in neurodegenerative diseases. In this study we aimed to investigate whether the noncompetitive NMDAR antagonist MK801 protects against 1-BP-induced cognitive dysfunction. Male Wistar rats were administered with MK801 (0.1 mg/kg) prior to 1-BP intoxication (800 mg/kg). Their cognitive performance was evaluated by the Morris water maze test. The brains of rats were dissected for biochemical, neuropathological, and immunological analyses. We found that the spatial learning and memory were significantly impaired in the 1-BP group, and this was associated with neurodegeneration in both the hippocampus (especially CA1 and CA3) and cortex. Besides, the protein levels of phosphorylated NMDARs were increased after 1-BP exposure. MK801 ameliorated the 1-BP-induced cognitive impairments and degeneration of neurons in the hippocampus and cortex. Mechanistically, MK801 abrogated the 1-BP-induced disruption of excitatory and inhibitory amino-acid balance and NMDAR abnormalities. Subsequently, MK801 inhibited the microglial activation and release of pro-inflammatory cytokines in 1-BP-treated rats. Our findings, for the first time, revealed that MK801 protected against 1-BP-induced cognitive dysfunction by ameliorating NMDAR function and blocking microglial activation, which might provide a potential target for the treatment of 1-BP poisoning.
Animals ; Brain ; drug effects ; metabolism ; pathology ; Cognitive Dysfunction ; drug therapy ; metabolism ; pathology ; Disease Models, Animal ; Dizocilpine Maleate ; pharmacology ; Excitatory Amino Acid Antagonists ; pharmacology ; Hydrocarbons, Brominated ; Inflammasomes ; drug effects ; metabolism ; Male ; Maze Learning ; drug effects ; physiology ; Microglia ; drug effects ; metabolism ; pathology ; NLR Family, Pyrin Domain-Containing 3 Protein ; metabolism ; Neurons ; drug effects ; metabolism ; pathology ; Nootropic Agents ; pharmacology ; Random Allocation ; Rats, Wistar ; Receptors, N-Methyl-D-Aspartate ; antagonists & inhibitors ; metabolism ; Spatial Memory ; drug effects ; physiology ; Specific Pathogen-Free Organisms

OBJECTIVE: To investigate the anti-neuroinflammation effect of extract of Fructus Schisandrae chinensis (EFSC) on lipopolysaccharide (LPS)-induced BV-2 cells and the possible involved mechanisms. METHODS: Primary cortical neurons were isolated from embryonic (E17-18) cortices of Institute of Cancer Research (ICR) mouse fetuses. Primary microglia and astroglia were isolated from the frontal cortices of newborn ICR mouse. Different cells were cultured in specific culture medium. Cells were divided into 5 groups: control group, LPS group (treated with 1 μg/mL LPS only) and EFSC groups (treated with 1 μg/mL LPS and 100, 200 or 400 mg/mL EFSC, respectively). The effect of EFSC on cells viability was tested by methylthiazolyldiphenyltetrazolium bromide (MTT) colorimetric assay. EFSC-mediated inhibition of LPS-induced production of pro-inflammatory mediators, such as nitrite oxide (NO) and interleukin-6 (IL-6) were quantified and neuron-protection effect against microglia-mediated inflammation injury was tested by hoechst 33258 apoptosis assay and crystal violet staining assay. The expression of pro-inflammatory marker proteins was evaluated by Western blot analysis or immunofluorescence. RESULTS: EFSC (200 and 400 mg/mL) reduced NO, IL-6, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in LPS-induced BV-2 cells (P<0.01 or P<0.05). EFSC (200 and 400 mg/mL) reduced the expression of NO in LPS-induced primary microglia and astroglia (P<0.01). In addition, EFSC alleviated cell apoptosis and inflammation injury in neurons exposed to microglia-conditioned medium (P<0.01). The mechanistic studies indicated EFSC could suppress nuclear factor (NF)-?B phosphorylation and its nuclear translocation (P<0.01). The anti-inflammatory effect of EFSC occurred through suppressed activation of mitogen-activated protein kinase (MAPK) pathway (P<0.01 or P<0.05). CONCLUSION EFSC acted as an anti-inflammatory agent in LPS-induced glia cells. These effects might be realized through blocking of NF-κB activity and inhibition of MAPK signaling pathways.
Animals ; Astrocytes ; drug effects ; metabolism ; pathology ; Cell Line ; Cell Nucleus ; drug effects ; metabolism ; Chromatography, High Pressure Liquid ; Down-Regulation ; drug effects ; Inflammation ; pathology ; Inflammation Mediators ; metabolism ; Lipopolysaccharides ; MAP Kinase Signaling System ; drug effects ; Mice, Inbred ICR ; Microglia ; drug effects ; metabolism ; pathology ; NF-kappa B ; metabolism ; Nervous System ; pathology ; Neurons ; drug effects ; metabolism ; pathology ; Neuroprotective Agents ; pharmacology ; Plant Extracts ; pharmacology ; Schisandra ; chemistry ; Spectrometry, Mass, Electrospray Ionization

PURPOSETo investigate the effects of estrogen G protein-coupled receptor 30 (GPR30) agonist G1 on hippocampal neuronal apoptosis and microglial polarization in rat traumatic brain injury (TBI).

METHODSMale SD rats were randomly divided into sham group, TBI + vehicle group, TBI + G1 group. Experimental moderate TBI was induced using Feeney's weigh-drop method. G1 (100μg/kg) or vehicle was intravenously injected from femoral vein at 30 min post-injury. Rats were sacrificed at 24 h after injury for detection of neuronal apoptosis and microglia polarization. Neuronal apoptosis was assayed by immunofluorescent staining of active caspase-3. M1 type microglia markers (iNOS and IL-1β) and M2 type markers (Arg1 and IL-4) were examined by immunoblotting or ELISA. Total protein level of Akt and phosphorylated Akt were assayed by immunoblotting.

RESULTSG1 significantly reduced active caspase-3 positive neurons in hippocampus. Meanwhile G1 increased the ratio of Arg1/iNOS. IL-1β production was decreased but IL-4 was increased after G1 treatment. G1 treatment also increased the active form of Akt.

CONCLUSIONSGPR30 agonist G1 inhibited neuronal apoptosis and favored microglia polarization to M2 type.

Animals ; Apoptosis ; drug effects ; Brain Injuries, Traumatic ; drug therapy ; pathology ; Cell Polarity ; Hippocampus ; drug effects ; Interleukin-1beta ; biosynthesis ; Male ; Microglia ; drug effects ; Neurons ; drug effects ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; agonists

OBJECTIVETo investigate whether analgesic effect of electroacupuncture (EA) is affected by p38 mitogen-activated protein kinase (p38 MAPK) on microglia.

METHODSThere were two experiments. The experiment 1: 40 male Sprague-Dawley (SD) rats were randomly divided into the normal, surgery, EA and sham EA groups, and the L5 spinal nerve ligation (SNL) on the right side was used to establish neuropathic pain model. EA was applied to bilateral Zusanli (ST36) and Kunlun (BL60) at 24, 48 and 72 h after SNL for 30 min, once per day. The paw withdrawal thresholds (PWTs) were measured before surgery (as base) and at 24, 25, 49 and 73 h after surgery. Phospho-p38 MAPK (p-p38 MAPK), oxycocin-42 (OX-42, marker of microglia), and glial fibrillary acidic protein (GFAP, marker of astrocyte) in bilateral spinal cord dorsal horn (SCDH) were detected by immunofluorescence, respectively. The experiment 2: 40 male SD rats were cannulated for SNL-induced neuropathic pain, and then were randomly divided into the dimethyl sulfoxide (DMSO), EA plus DMSO, 4-(4-fluorophenyl)-2-(4-methylsulfonylpheny)-5-(4-pyridyl)-1H-imidazole (SB203580) and EA plus SB203580 groups. SB203580 (30 nmol/L) was administered 5 min prior to EA treatment. The PWTs and OX-42 in bilateral SCDH were measured as mentioned above.

RESULTSSNL-induced neuropathic pain reduced PWTs and increased the expression of p-p38 MAPK and OX-42 in bilateral lumbar SCDH of rats (P<0.01). Spinal p-p38 MAPK was only co-localized with OX-42 in our study. EA treatment significantly alleviated SNL-mediated mechanical hyperalgesia, and suppressed the expression of p-p38 MAPK and OX-42 in lumbar SCDH (P<0.05 or P<0.01). Intrathecal injection of low dose SB203580 had no influence on PWTs (P>0.05), but significantly inhibited the expression of OX-42 positive cells in bilateral SCDH (P<0.01 or P<0.05). EA plus SB203580 synergistically increased PWTs, and reduced the expression of bilateral spinal OX-42 (P<0.01 or P<0.05).

CONCLUSIONSThe central mechanism of EA-induced anti-hyperalgesia may be partially associated with the reduced expression of p-p38 MAPK, and subsequently reducing the activation of OX-42 in neuropathic pain. Therefore, EA may be a new complementary and alternative therapy for neuropathic pain.

Animals ; Biomarkers ; metabolism ; CD11b Antigen ; metabolism ; Electroacupuncture ; Fluorescent Antibody Technique ; Hyperalgesia ; pathology ; therapy ; Imidazoles ; pharmacology ; Ligation ; Male ; Microglia ; drug effects ; enzymology ; pathology ; Neuroglia ; drug effects ; metabolism ; Phosphorylation ; drug effects ; Posterior Horn Cells ; drug effects ; enzymology ; pathology ; Pyridines ; pharmacology ; Rats, Sprague-Dawley ; Spinal Nerves ; drug effects ; pathology ; p38 Mitogen-Activated Protein Kinases ; metabolism

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

Aggregation and accumulation of beta-amyloid peptide (Abeta) in brain tissues contribute to the pathogenesis of Alzheimer's disease. Therefore, the promotion of Abeta clearance is one of the key targets for preventing and treatment Alzheimer's disease. Studies proved that some traditional Chinese medicine (TCM) compounds and extracts could impact the activity of degrading enzyme in amyloid peptide, the transport of hemato encephalic barrier and the phagocytosis of microglial cells, promote Abeta clearance, and improve learning and memory of animal models with Alzheimer's disease. In this review, we made an summary for the relations between Abeta and Alzheimer's disease, the Abeta clearance mechanism and the clearance effect of traditional Chinese medicines.
Alzheimer Disease ; drug therapy ; metabolism ; pathology ; Amyloid beta-Peptides ; chemistry ; metabolism ; Animals ; Blood-Brain Barrier ; drug effects ; metabolism ; Humans ; Medicine, Chinese Traditional ; methods ; Microglia ; drug effects ; metabolism ; Protein Multimerization ; drug effects

OBJECTIVE: To observe the effect of Naoling decoction on the learning and memory behaviors and the expression of microglia and IL-6 in hippocampal CA3 region of rats with Alzheimer's disease (AD), and to elucidate the potential mechanism. METHODS: Thirty SD rats were randomly divided into 5 groups: a normal group, a sham-operation group, an AD group, a Naoling decoction group and a Naofukang group. The spatial learning and memory behaviors of the rats were investigated by water maze and Y-maze. The Alzheimer's disease model was established by injecting Aβ1-42 into the hippocamal of the rats. Expression of OX-42 (one of the microglia specific markers) and IL-6 in the CA3 region of hippocamal was measured by immunohistochemical stain. RESULTS: Morris water maze experiment showed that the escape latency of hidden platform in the AD group was significantly delayed (P<0.05) and the average times of passing was decreased (P<0.05). Y-maze test showed that the times needed to the learn how to evade the electrical stimulation in the AD group was most than in other groups (P<0.05). Compared with the AD group, the Morris water maze test and Y-maze test of the Naoling decoction group were significantly different (P<0.05). The expression of OX-42 and IL-6 in the CA3 region of hippocamal in the Naoling decoction group was decreased (P<0.05). CONCLUSION Naoling decoction can improve learning and memory, and weaken the expression of OX-42 and IL-6 in hippocampal CA3 of AD rats, which may partly be the therapeutic mechanism of Naoling decoction for AD.
Alzheimer Disease ; drug therapy ; metabolism ; Animals ; CA3 Region, Hippocampal ; metabolism ; pathology ; Disease Models, Animal ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Interleukin-6 ; genetics ; metabolism ; Learning ; drug effects ; Male ; Memory ; drug effects ; Microglia ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effect of the iron chelator deferoxamine (DFA) in suppressing microglia activation and protecting against secondary neural injury in a rat model of intracerebral hemorrhage (ICH).

METHODSSD rats were randomly divided into sham-operated group, ICH group and DFA treatment group. ICH model was established by infusion of type IV collagenase into the right basal ganglia, and starting from 1 h after the operation, the rats received intraperitoneal DFA injections every 12 h for 7 days. The iron content in the perihematoma brain tissue was determined at different time points after DFA administration, and OX42 immunohistochemistry was used to observe the changes in the microglia. The contents of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the brain tissue were detected by ELISA. The neural death and neurological deficiency were measured using Nissl staining and neurological scores, respectively.

RESULTSThe iron content in the brain tissues around the hematoma was significantly increased 3 days after ICH and maintained a high level till 28 days, accompanied by a marked increase of microglial cells as compared to the sham-operated group. DFA injection caused significantly decreased iron content in the brain tissue, reduced number of microglial cells, and lowered levels of IL-1β and TNF-α. Neuronal loss around the hematoma was obviously reversed after DFA injections, which resulted in improved neurological deficiency.

CONCLUSIONDFA can suppress microglia activation by removing iron overload from the perihematoma brain tissue, thus reducing secondary neuronal death and neurological deficiency in rats with ICH.

Animals ; Cerebral Hemorrhage ; metabolism ; pathology ; Deferoxamine ; pharmacology ; Interleukin-1beta ; metabolism ; Iron ; metabolism ; Male ; Microglia ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; metabolism

Microglia are the principal immune effectors in brain and participate in a series ofneurodegenerative diseases. The microglial shapes are highly plastic. The morphology is closely related with their activation status and biological functions. Cerebral ischemia could induce microglial activation, and microglial activation is subjected to precise regulation. Microglia could play either protective or neurotoxic roles in cerebral ischemia. Therefore, regulating the expression of receptors or protein molecules on microglia, inhibiting the excessive activation of microglia and production of pro-inflammatory factors, promoting the release of neuroprotective substances might be beneficial to the treatment of cerebral ischemia. The study about relationship between microglia and cerebral ischemia will shed a light on the treatment of cerebral ischemia. This paper is a review of microglial activation and regulation during cerebral ischemia as well as related therapeutic methods.
Animals ; Brain Ischemia ; metabolism ; pathology ; Class Ib Phosphatidylinositol 3-Kinase ; metabolism ; Humans ; Inflammation ; metabolism ; Microglia ; cytology ; drug effects ; metabolism ; physiology ; Neuroprotective Agents ; pharmacology ; Nitric Oxide Synthase ; metabolism ; Receptors, Purinergic P2X7 ; metabolism ; Regeneration ; TNF-Related Apoptosis-Inducing Ligand ; metabolism ; Toll-Like Receptors ; metabolism

OBJECTIVETo investigate the effects of caffeic acid ester fraction (Caf) from Erigeron breviscapus, mainly composed of dicaffeoylquinic acids (diCQAs), on microglial activation in vitro and focal cerebral ischemia in vivo.

METHODSThe production of nitric oxide (NO), tumor necrosis factor α (TNF-α), and interleukin-1β (IL-1β) induced by lipopolysaccharide (LPS) treatment in rat primary cultured microglia were measured by Griess reaction or enzyme-linked immunosorbent assay. Cell viability of cortical neurons was measured using AlamarBlue reagent. The behavioral tests and the infarct area of brain were used to evaluate the damage to central nervous system in rat middle cerebral artery occlusion (MCAO) model of cerebral ischemia. Real time polymerase chain reaction was used to determine the expression of inducible nitric oxide synthase (iNOS), TNF-α and IL-1β mRNA in ischemic cerebral tissues.

RESULTSCaf inhibited the production of NO, TNF-α and IL-1β induced by LPS treatment in primary microglia in a dose-dependent manner. Exposure of cortical neurons to conditioned medium from Caf-treated microglia increased neuronal cell viability (P<0.01) compared with conditioned medium from LPS-treated alone. In MCAO rat model of cerebral ischemia, Caf could significantly improve neurobehavioural performance and reduce percentage infarct volume compared with the vehicle group (P<0.05). Caf could also significantly inhibit the up-regulation of iNOS, TNF-α, and IL-1β gene expressions in ischemic cerebral tissues.

CONCLUSIONCaf could suppress microglial activation, which may be one mechanism of its neuroprotective effect against ischemia.

Animals ; Brain ; drug effects ; metabolism ; pathology ; Brain Ischemia ; complications ; drug therapy ; pathology ; prevention & control ; Caffeic Acids ; chemistry ; pharmacology ; Chemical Fractionation ; Chromatography, High Pressure Liquid ; Erigeron ; chemistry ; Gene Expression Regulation ; drug effects ; Infarction, Middle Cerebral Artery ; complications ; pathology ; Interleukin-1beta ; genetics ; metabolism ; Microglia ; drug effects ; metabolism ; pathology ; Neuroprotective Agents ; chemistry ; pharmacology ; therapeutic use ; Nitric Oxide Synthase Type II ; genetics ; metabolism ; Plant Extracts ; pharmacology ; Quinic Acid ; analogs & derivatives ; chemistry ; pharmacology ; therapeutic use ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Tumor Necrosis Factor-alpha ; genetics ; metabolism