OBJECTIVETo observe the changes in the expression of neuroal nitric oxide synthase (nNOS) and glial fibrillary acidic protein (GFAP) in dentate gyrus (DG) of rats with Parkinson's disease (PD) and effects of electroacupuncture (EA).

METHODSOn the 7th day of stereotactic injection with 6-hydroxydopamine into right medial forebrain bundle, apomorphine-induced rotation was carried out to select the PD rats. The selected 12 rats were randomly divided into a model group (n = 6) and an EA group (n = 6). Moreover a normal group was established (n = 6). Then, the rats in EA group were treated with EA at "Hegu" (LI 4) and "Taichong" (LR 3), once a day for 21 days, and the other groups without any treatment. After EA treatment, the expressions of nNOS and GFAP in right DG were examined by immunohistochemistry method.

RESULTSThe expression of nNOS in the right DG was weak in normal group, and the expression of nNOS in model group was significantly higher than that in normal group (P < 0.01), while in EA group, it was significantly lower than that in model (P < 0.01), with no difference between EA group and normal group (P > 0.05). The expression level of GFAP in model group was significantly higher than that in normal group (P < 0.01), while there was no difference in the number of GFAP positive cells between the above two groups (P > 0.05), and the number of GFAP positive cells in EA group was significantly increased compared with that in model group (P < 0.01), while with no significant difference in the expression level of GFAP between EA group and model group (P > 0.05).

CONCLUSIONEA can reverse the increase of nNOS expression and promote the activation of astrocyte in DG on the injured side in rats with PD.

Animals ; Astrocytes ; enzymology ; Dentate Gyrus ; cytology ; enzymology ; Electroacupuncture ; Humans ; Male ; Nitric Oxide Synthase ; genetics ; metabolism ; Parkinson Disease ; enzymology ; genetics ; therapy ; Rats ; Rats, Sprague-Dawley

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

Neuronal nitric oxide synthase (nNOS) is constitutively expressed in neurons of the central nervous system, where it plays a physiological role in neurotransmission. In this study, we examined the functional role of nNOS in experimental autoimmune encephalomyelitis(EAE). The effects of the specific nNOS inhibitor 7-nitroindazole on normal and EAE rats were studied by immunohistochemistry and Western blot analysis. We found that nNOS is constitutively expressed in the spinal cords of normal rats, whilst in the spinal cords of EAE rats, nNOS expression slightly increased, concomitant with the infiltration of T cells and macrophages. Immunohistochemical studies showed that nNOS expression in macrophages and astrocytes increased at the peak stage of EAE and declined thereafter. Treatment with 7-nitroindazole (30 mg/kg) significantly delayed the onset of EAE paralysis, but had no effect on either the incidence or the severity of the paralysis. These findings suggest that nNOs inhibition has a limited role in the induction of rat EAE, and that constitutive nNOS in the spinal cord functions as a novel neurotransmitter, rather than a pro-inflammatory agent.
Animals ; Astrocytes/*enzymology ; Blotting, Western ; Encephalomyelitis, Autoimmune, Experimental/drug therapy/*enzymology ; Enzyme Inhibitors/therapeutic use ; Immunohistochemistry ; Indazoles/therapeutic use ; Macrophages/*enzymology ; Male ; Nitric Oxide Synthase/antagonists&inhibitors/*metabolism ; Rats ; Rats, Inbred Lew ; Spinal Cord/cytology/*enzymology

OBJECTIVETo explore the expression of p-p38 MAPK protein and the number of astrocytes expressing p-p38 MAPK in CA1 hippocampus in rats during the induction of brain ischemic tolerance induced by intermittent hypobaric hypoxia (IH) preconditioning.

METHODSThirty healthy adult male Wistar rats were randomly divided into 6 groups (n = 5 in each group): sham 0 min group, IH + sham 0 min group, sham 7 d group, IH + sham 7 d group, Ischemia (Is) 7 d group, and IH + Is 7 d group. Neuropathological evaluation was performed by thionine staining in CA1 hippocampus in rats. The expression of p-p38 MAPK in CA1 hippocampus was observed by immunohistochemical staining. And the number of astrocytes expressing p-p38 MAPK was observed by immunofluorescent double labeling.

RESULTSThe results showed that IH preconditioning induced brain ischemic tolerance successfully. At the same time, IH preconditioning obviously up-regulated the expression of p-p38 MAPK protein in CA1 hippocampus, and also increased the number of astrocytes expressing p-p38 MAPK.

CONCLUSIONIt might be concluded that IH preconditioning induced brain ischemic tolerance by up-regulating the expression of p-p38 MAPK protein in pyramidal neurones and astrocytes.

Animals ; Astrocytes ; enzymology ; pathology ; Brain Ischemia ; enzymology ; pathology ; Disease Models, Animal ; Hippocampus ; enzymology ; Hypoxia ; Ischemic Preconditioning ; methods ; Male ; Phosphorylation ; Pressure ; Rats ; Rats, Wistar ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo investigate the protective effect of mild hypothermia on rat astrocytes with traumatic or ischemic injury.

METHODSRat astrocytes in primary culture were subjected to scratching or hypoxic injury and exposed to normothermia (37 degrees celsius;) or hypothermia (34 or 32 degrees celsius;) for 24 h. The morphology of the astrocytes was evaluated by live/dead staining, and the cell injury was measured by lactate dehydrogenase (LDH) release assay.

RESULTSAs the temperature reduced the LDH release rate from the cells in hypoxic group decreased significantly, to (11.48 - or + 1.53)% at 34 degrees celsius; and (3.79 - or + 0.45)% at 32 degrees celsius; as compared to that in normothermia [(33.02 - or + 3.58)%] in the absence of rat white blood cells (WBC) (P<0.001). LDH release rate of the hypoxic cells further decreased in the presence of rat WBC to (51.14 - or + 2.17 )% at 37 degrees celsius;, (19.53 - or + 4.37)% at 34 degrees celsius; and (16.68 - or + 1.47)% at 32 degrees celsius; (P<0.001). In the scratched cells, with or without WBC, LDH release rate showed no significant variation between the 3 temperatures (P>0.05).

CONCLUSIONMild hypothermia offers obvious protective effects on rat astrocytes against ischemic damage but not against mechanical injury.

Animals ; Animals, Newborn ; Astrocytes ; enzymology ; pathology ; Brain Injuries ; therapy ; Brain Ischemia ; therapy ; Cell Hypoxia ; Cells, Cultured ; Cold Temperature ; L-Lactate Dehydrogenase ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

The relevance of transglutaminases with neural function and several disorders has been emphasized recently. Especially, many polypeptides associated with neurodegenerative diseases are suggested to be putative transglutaminase substrates such as beta amyloid protein of Alzheimer's disease, microtubule-associated proteins and neurofilaments, etc. In addition, the CAG repeated gene products with probable polyglutamine tract, putative transglutaminase substrates, were identified in several neurodegenerative disorders. However, the identity of the brain transglutaminase has not been confirmed, because of enzymic stability and low activity. In the present experiment, we have isolated brain-specific transglutaminases, designated as TGase NI and TGase NII, which are different from other types of transglutaminases in respects of molecular weights (mw. 45 kDa, 29 kDa respectively), substrate affinity, elution profile on ion-exchange chromatography, sensitivity to proteases and ethanol, and immunological properties. The enzymes were localized specifically in the brain tissues but not in the liver tissue. And neural cells such as pheochromocytoma cell, glioma cell, primary neuronal and glial cells were shown to be enriched with TGase NI and TGase NII. The possible biological roles of the enzymes were discussed not only on the aspect of crosslinking activity but also of signal transducing capacity of the enzyme in the brain.
Animal ; Astrocytes/enzymology ; Blotting, Western ; Brain/enzymology* ; Calcium/metabolism ; Chromatography, Ion Exchange ; Endopeptidases/pharmacology ; Enzyme Stability ; Ethanol/pharmacology ; Glioma ; Immunoblotting ; Immunohistochemistry ; Male ; Molecular Weight ; Neurons/enzymology ; PC12 Cells ; Protein-Glutamine gamma-Glutamyltransferase/isolation & purification* ; Protein-Glutamine gamma-Glutamyltransferase/immunology ; Protein-Glutamine gamma-Glutamyltransferase/chemistry* ; Rats ; Rats, Sprague-Dawley ; Trypsin/pharmacology ; Tumor Cells, Cultured

HIV-1 Tat is considered to be one of key players to facilitate monocyte entry into the CNS, which is characteristic feature of AIDS-related encephalitis and dementia. This study was performed to determine the regulatory function of superoxide dismutase (SOD) on the HIV-1 Tat-induced signaling pathways leading to NF-kappaB activation, expression of adhesion molecules, and monocyte adhesion in CRT-MG human astroglioma cells by using cell-permeable SOD. When cell-permeable SOD was added to the culture medium of CRT-MG cells, it rapidly entered the cells in dose- and time-dependent manners. Treatment of astrocytes with cell-permeable SOD led to decrease in Tat-induced ROS generation as well as NF-kappaB activation. Cell-permeable SOD inhibited the activation of MAP kinases including ERK, JNK and p38 by HIV-1 Tat. Treatment of CRT-MG cells with cell-permeable SOD significantly inhibited protein and mRNA levels of ICAM-1 and VCAM-1 up-regulated by HIV-1 Tat, as measured by Western blot analysis and RT-PCR. Furthermore, enhanced adhesiveness of monocyte to astrocyte by HIV-1 Tat was significantly abrogated by pretreatment with cell-permeable SOD fusion proteins. These data indicate that SOD has a regulatory function for HIV-1 Tat-induced NF-kappaB activation in astrocytes and suggest that cell-permeable SOD can be used as a feasible therapeutic agent for regulation of ROS-related neurological diseases.
Astrocytes/*enzymology ; Cell Adhesion/*physiology ; Cell Membrane Permeability ; Gene Products, tat/*pharmacology ; HIV Infections/metabolism ; HIV-1/*chemistry ; Humans ; Monocytes/cytology/*drug effects ; Signal Transduction ; Superoxide Dismutase/genetics/*physiology

Astrocytes are the most abundant cells in the central nervous system that play roles in maintaining the blood-brain-barrier and in neural injury, including cerebral malaria, a severe complication of Plasmodium falciparum infection. Prostaglandin (PG) D2 is abundantly produced in the brain and regulates the sleep response. Moreover, PGD2 is a potential factor derived from P. falciparum within erythrocytes. Heme oxygenase-1 (HO-1) is catalyzing enzyme in heme breakdown process to release iron, carbon monoxide, and biliverdin/bilirubin, and may influence iron supply to the P. falciparum parasites. Here, we showed that treatment of a human astrocyte cell line, CCF-STTG1, with PGD2 significantly increased the expression levels of HO-1 mRNA by RT-PCR. Western blot analysis showed that PGD2 treatment increased the level of HO-1 protein, in a dose- and time-dependent manner. Thus, PGD2 may be involved in the pathogenesis of cerebral malaria by inducing HO-1 expression in malaria patients.
Animals ; Astrocytes/*enzymology ; Blotting, Western ; Cell Line ; Gene Expression Profiling ; Heme Oxygenase-1/*biosynthesis ; Humans ; Malaria, Cerebral/*pathology ; Malaria, Falciparum/*complications/*pathology ; Plasmodium falciparum/*pathogenicity ; Prostaglandins/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the role of extracellular signal-regulated kinase1/2 (ERK1/2) pathway in the regulation of aquaporin 4 (AQP4) expression in cultured astrocytes after scratch-injury.

METHODSThe scratch-injury model was produced in cultured astrocytes of rat by a 10-μL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase (LDH) leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2 (p-ERK1/2) expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 µmol/L U0126 (ERK1/2 inhibitor) was incubated in the medium at 30 min before the scratch-injury in some groups.

RESULTSIncreases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury.

CONCLUSIONThese results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.

Animals ; Aquaporin 4 ; metabolism ; Astrocytes ; enzymology ; metabolism ; Butadienes ; administration & dosage ; Cells, Cultured ; Down-Regulation ; Enzyme Activation ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; MAP Kinase Signaling System ; Nitriles ; administration & dosage ; Rats ; Rats, Wistar ; Skin ; injuries

The infiltration of monocytes into the CNS represents one of the early steps to inflammatory events in AIDS-related encephalitis and dementia. Increased activity of selected matrix metalloproteinases (MMPs) such as MMP-9 impairs the integrity of blood-brain barrier leading to enhanced monocyte infiltration into the CNS. In this study, we examined the effect of HIV-1 Tat on the expression of MMP-9 in CRT-MG human astroglioma cells. Treatment of CRT-MG cells with HIV-1 Tat protein significantly increased protein levels of MMP-9, as measured by Western blot analysis, zymography and an ELISA. Treatment of CRT-MG cells with HIV-1 Tat protein markedly increased mRNA levels of MMP-9, as analyzed by RT-PCR. Pretreatment of CRT-MG cells with NF-kappaB inhibitors led to decrease in Tat-induced protein and mRNA expression of MMP-9. Pretreatment of CRT-MG cells with MAPK inhibitors suppressed Tat-induced MMP-9 expression. Furthermore, HIV-1 Tat-induced expression of MMP-9 was significantly inhibited by neutralization of TNF-alpha, but not IL-1beta and IL-6. Taken together, our results indicate that HIV-1 Tat can up-regulate expression of MMP-9 via MAPK-NF-kappaB-dependent mechanisms as well as Tat-induced TNF-alpha production in astrocytes.
AIDS Dementia Complex/*metabolism ; Astrocytes/*drug effects/enzymology ; HIV Infections/*complications ; *HIV-1 ; Humans ; Matrix Metalloproteinase 9/*genetics/immunology ; Mitogen-Activated Protein Kinase Kinases/*metabolism ; NF-kappa B/*metabolism ; Tumor Cells, Cultured ; Tumor Necrosis Factor-alpha/immunology/metabolism ; Up-Regulation/drug effects ; tat Gene Products, Human Immunodeficiency Virus/*metabolism