PURPOSE: To investigate whether dexmedetomidine (Dex) can reduce the production of inflammatory factor IL-1β by inhibiting the activation of NLRP3 inflammasome in hippocampal microglia, thereby alleviating the inflammatory response of the central nervous system induced by surgical injury. METHODS: Exploratory laparotomy was used in experimental models in this study. Totally 48 Sprague Dawley male rats were randomly divided into 4 groups (n = 12 for each), respectively sham control (group A), laparotomy only (group B); and Dex treatment with different doses of 5 μg/kg (group D1) or 10 μg/kg (group D2). Rats in groups D1 and D2 were intraperitoneally injected with corresponding doses of Dex every 6 h. The rats were sacrificed 12 h after operation; the hippocampus tissues were isolated, and frozen sections were made. The microglia activation was estimated by immunohistochemistry. The protein expression of NLRP3, caspase-1, ASC and IL-1β were detected by immunoblotting. All data were presented as mean ± standard deviation, and independent sample t test was used to analyze the statistical difference between groups. RESULTS: The activated microglia in the hippocampus of the rats significantly increased after laparotomy (group B vs. sham control, p < 0.01). After Dex treatment, the number was decreased in a dose-dependent way (group D1 vs. D2, p < 0.05), however the activated microglia in both groups were still higher than that of sham controls (both p < 0.05). Further Western blot analysis showed that the protein expression levels of NLRP3, caspase-1, ASC and downstream cytokine IL-1β in the hippocampus from the laparotomy group were significantly higher than those of the sham control group (all p < 0.01). The elevated expression of these proteins was relieved after Dex treatment, also in a dose-dependent way (D2 vs. D1 group, p < 0.05). CONCLUSION Dex can inhibit the activation of microglia and NLRP3 inflammasome in the hippocampus of rats after operation, and the synthesis and secretion of IL-1β are also reduced in a dose-dependent manner by using Dex. Hence, Dex can alleviate inflammation activation on the central nervous system induced by surgical injury.
Animals ; Dexmedetomidine ; administration & dosage ; pharmacology ; Dose-Response Relationship, Drug ; Hippocampus ; metabolism ; Immunohistochemistry ; Inflammasomes ; metabolism ; Inflammation Mediators ; metabolism ; Injections, Intraperitoneal ; Interleukin-1beta ; metabolism ; Laparotomy ; adverse effects ; Male ; Microglia ; metabolism ; NLR Family, Pyrin Domain-Containing 3 Protein ; metabolism ; Rats, Sprague-Dawley ; Time Factors

Gastrodin is a phenolic glycoside that has been demonstrated to provide neuroprotection in preclinical models of central nervous system disease, but its effect in subarachnoid hemorrhage (SAH) remains unclear. In this study, we showed that intraperitoneal administration of gastrodin (100 mg/kg per day) significantly attenuated the SAH-induced neurological deficit, brain edema, and increased blood-brain barrier permeability in rats. Meanwhile, gastrodin treatment significantly reduced the SAH-induced elevation of glutamate concentration in the cerebrospinal fluid and the intracellular Ca overload. Moreover, gastrodin suppressed the SAH-induced microglial activation, astrocyte activation, and neuronal apoptosis. Mechanistically, gastrodin significantly reduced the oxidative stress and inflammatory response, up-regulated the expression of nuclear factor erythroid 2-related factor 2, heme oxygenase-1, phospho-Akt and B-cell lymphoma 2, and down-regulated the expression of BCL2-associated X protein and cleaved caspase-3. Our results suggested that the administration of gastrodin provides neuroprotection against early brain injury after experimental SAH.
Animals ; Apoptosis ; drug effects ; Astrocytes ; drug effects ; metabolism ; Benzyl Alcohols ; administration & dosage ; Blood-Brain Barrier ; drug effects ; metabolism ; Brain ; drug effects ; metabolism ; Brain Edema ; etiology ; prevention & control ; Calcium ; metabolism ; Glucosides ; administration & dosage ; Glutamic Acid ; metabolism ; Male ; Microglia ; drug effects ; metabolism ; Neurons ; drug effects ; Neuroprotective Agents ; administration & dosage ; Oxidative Stress ; drug effects ; Rats, Sprague-Dawley ; Subarachnoid Hemorrhage ; complications ; metabolism ; prevention & control

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

OBJECTIVE: : To determine the effects of cysteinyl leukotriene receptors (CysLTR and CysLTR) on phagocytosis of mouse BV2 microglial cells. METHODS: : BV2 cells were stimulated with microglial activators lipopolysaccharide (LPS) or CysLT receptor agonists LTD. The phagocytosis of BV2 cells was observed by immunofluorescence analysis and flow cytometry. The intracellular distributions of CysLTR and CysLTR in BV2 cells were examined with immunofluorescence staining. RESULTS: : Both LPS and LTD could significantly enhance the phagocytosis of BV2 cells, and such effect could be inhibited by CysLTR selective antagonist Montelukast and CysLTR selective antagonist HAMI 3379. The activation of BV2 cells induced by LTD or LPS resulted in changes in intracellular distributions of CysLTR and CysLTR. CysLTR and CysLTR was co-localization with a similar distribution. CONCLUSIONS : CysLTR and CysLTR regulate the phagocytosis of mouse BV2 microglial cells with a synergistic effect.
Acetates ; pharmacology ; Animals ; Cell Line ; Cyclohexanecarboxylic Acids ; pharmacology ; Lipopolysaccharides ; pharmacology ; Mice ; Microglia ; cytology ; Phagocytosis ; drug effects ; Phthalic Acids ; pharmacology ; Protein Binding ; drug effects ; Quinolines ; pharmacology ; Receptors, Leukotriene ; agonists ; metabolism

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

Emerging evidence indicates that microglia activation plays an important role in spinal cord injury (SCI) caused by trauma. Studies have found that inhibiting the Rho/Rho-associated protein kinase (ROCK) signaling pathway can reduce inflammatory cytokine production by microglia. In this study, Western blotting was conducted to detect ROCK2 expression after the SCI; the ROCK Activity Assay kit was used for assay of ROCK pathway activity; microglia morphology was examined using the CD11b antibody; electron microscopy was used to detect microglia phagocytosis; TUNEL was used to detect tissue cell apoptosis; myelin staining was performed using an antibody against myelin basic protein (MBP); behavioral outcomes were evaluated according to the methods of Basso, Beattie, and Bresnahan (BBB). We observed an increase in ROCK activity and microglial activation after SCI. The microglia became larger and rounder and contained myelin-like substances. Furthermore, treatment with fasudil inhibited neuronal cells apoptosis, alleviated demyelination and the formation of cavities, and improved motor recovery. The experimental evidence reveals that the ROCK inhibitor fasudil can regulate microglial activation, promote cell phagocytosis, and improve the SCI microenvironment to promote SCI repair. Thus, fasudil may be useful for the treatment of SCI.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine ; analogs & derivatives ; pharmacology ; therapeutic use ; Animals ; Apoptosis ; Male ; Microglia ; drug effects ; metabolism ; Myelin Basic Protein ; metabolism ; Myelin Sheath ; metabolism ; Phagocytosis ; Protein Kinase Inhibitors ; pharmacology ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Injuries ; drug therapy ; rho-Associated Kinases ; antagonists & inhibitors ; metabolism

OBJECTIVETo observe the effect of Yangxue Qingnao Granule (YQG) on the expression of CD11b in CA1 region of hippocampus of vascular dementia rats, and to explore its regulation on microglias.

METHODSTotally 144 SD rats were randomly divided into the sham-operation group, the vascular dementia model group (model), and the YQG treated group (treated). The vascular dementia rat model was prepared by modified Pulsinelli's four-vessel occlusion. Rats in the sham-operation group and the model group were administered with normal saline -(at the daily dose of 10 mL/kg) by gastrogavage, while those in the treated group were administered with YQG (0.32 g/mL, at the daily dose of 10 mL/kg) by gastrogavage. All administration was performed once per day for 8 successive weeks. The expression of CD11b in CA1 region of hippocampus of vascular dementia rats was detected at week 1, 2, 4, and 8, respectively.

RESULTSCompared with the sham-operation group, the expression of CD11b in CA1 region of hippocampus of vascular dementia rats were significantly enhanced in the model group at each time point (P < 0.01). Compared with the model group, the expression of CD11b in CA1 region of hippocampus of vascular dementia rats significantly decreased in the treated group at each time point (P < 0.01), especially at week 2.

CONCLUSIONObvious activation and proliferation of microglias could be seen in CA1 region of hippocampus of vascular dementia rats, and YQG could inhibit activation and proliferation of microglias.

Animals ; CA1 Region, Hippocampal ; drug effects ; metabolism ; CD11b Antigen ; metabolism ; Dementia, Vascular ; drug therapy ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Microglia ; drug effects ; Random Allocation ; Rats ; Rats, Sprague-Dawley

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