To investigate the neutralizing effect of N-acetylcysteine (NAC) and selenium (Se) aganist doxorubicin (DOX) toxicity in rats, NAC (140 mg/kg, p.o.) and Se (0.5 mg/kg, p.o.) were administered for 2 days before DOX injection and then 3 times a week. Cell viability and the level of lipid peroxidation were examined in cultured-rat astrocytes. Severe morphologic changes in the kidney of DOX group; thickening of Bowmans capsule, presence of multifocal tubular casts were observed, but not in the other treated groups. Vacuoles in some hepatic cells and focal aggregation of stellate macrophages were also detected in DOX group, but not in the other treated groups. However, the severe inhibition of spermatogenesis was found in all treated groups. The cell viability of DOX (10 mg/ml) treated group and NAC (5 mM) or Se (0.001 mg/ml) combinedtreated group was 52.5+/-2.0 % , 85.3+/-4.5 % and 75.5+/-1.6 %, respectively. In MDA (malondialdehyde) assay, the level of lipid peroxidation on DOX (10 mg/ml), NAC (5 mM) and Se (0.001 mg/ml) was 0.77+/-0.06, 0.35+/-0.06 and 0.54+/-0.11 nmol/mg protein, respectively. Thus, it is known that NAC and Se have protective effects in kidney and liver but not in the testes. Morphological change was not detected in brain and heart in all groups for experiment period. From this in vitro study, it is known that NAC and Se protect well the astrocytes against DOX induced-cell damage.
Acetylcysteine/*pharmacology ; Animals ; Astrocytes/*cytology/drug effects/pathology ; Cell Survival/drug effects ; Cells, Cultured ; Doxorubicin/antagonists & inhibitors/*toxicity ; Liver/cytology/*drug effects/pathology ; Male ; Rats ; Rats, Sprague-Dawley ; Spermatocytes/cytology/drug effects/pathology

OBJECTIVETo investigate the apoptosis rules of the astrocytes and oligodendrocytes induced by Ca(2+) reperfusion.

METHODSThe apoptosis of purified cultured astrocytes and oligodendrocytes induced by Ca(2+) reperfusion and the relationship between the development of the cell apoptosis and post-reperfusion time was observed.

RESULTSBoth the astrocytes and oligodendrocytes were obviously in a time-dependent fashion, and the apoptosis ratios of the oligodendrocytes (39.73%+/-4.16%) were higher than the astrocytes (19.64%+/-4.67%) 24 hours after Ca(2+) reperfusion. The TUNEL positive cells were 13.6+/-1.82 and 21.4+/-1.95 at every visual field of astrocytes and oligodendrocytes respectively 24 hours after Ca(2+) reperfusion.

CONCLUSIONSThe astrocytes and oligodendrocytes are similar wi th the development rules on apoptosis and have different susceptiveness to the situation.

Animals ; Apoptosis ; drug effects ; physiology ; Astrocytes ; cytology ; pathology ; physiology ; Calcium ; physiology ; Cells, Cultured ; Flow Cytometry ; In Situ Nick-End Labeling ; Oligodendroglia ; cytology ; pathology ; physiology ; Rats ; Rats, Wistar

To study the relationship between tau hyperphosphorylation and the function of glutamate transporter okadaic acid (OA), a protein phosphatase inhibitor, 20 ng in a 0.5 microl volume, was injected into the frontal cortex of rat brain and immunostaining was used to observe the phosphorylation of tau protein and the expression of excitatory amino acid transporter 1 (EAAT1) in the brain following the injection. The results showed that (1) the neurons in the center of the injection region displayed cytoplasmic shrinkage, swelling, nuclear pyknosis, and dislocation at the early stage, and necrosis appeared 3 d after the injection. However, most neurons in the peri-injected areas showed normal morphological characters with immuno positive reaction for AT8, a tau phosphorylated marker; (2) morphological analysis showed that tau hyperphosphorylation caused by OA treatment was mainly observed in the axons and dendrites of neuronal cells at 6 h in the cell body at 1 d, which brought about dystrophic neurites and neurofibrillary tangle (NFT)-like pathological changes; (3) the induction of glutamate transporter EAAT1 was observed in the involved areas corresponding to that with AT8 immunopositive staining, and the number of EAAT1-positive staining cells markedly increased at 12 h (P<0.01), peaked at 1 d (P<0.001), then decreased at 3 d following the injection. Combined with a confocal laser scanning microscopic analysis, double fluorescent immunostaining showed that EAAT1 positive staining appeared in neurons as well as astrocytes in the peri-injected areas of the frontal cortex. These results demonstrate that OA increases glutamate transporter EAAT1 expression in neurons while it induces tau hyperphosphorylation. However, the mechanism and significance of the induction of glutamate transporter EAAT1 expression remain to be further elucidated.
Animals ; Astrocytes ; drug effects ; metabolism ; Axons ; drug effects ; metabolism ; Brain ; cytology ; Dendrites ; drug effects ; metabolism ; Excitatory Amino Acid Transporter 1 ; metabolism ; Neurofibrillary Tangles ; pathology ; Neurons ; drug effects ; metabolism ; Okadaic Acid ; pharmacology ; Phosphorylation ; Rats ; tau Proteins ; metabolism

MicroRNAs (miRNAs) are a class of noncoding RNAs that regulates target gene expression at posttranscriptional level, leading to further biological functions. We have demonstrated that microvesicles (MVs) can deliver miRNAs into target cells as a novel way of intercellular communication. It is reported that in central nervous system, glial cells release MVs, which modulate neuronal function in normal condition. To elucidate the potential role of glial MVs in disease, we evaluated the effects of secreted astrocytic MVs on stress condition. Our results demonstrated that after Lipopolysaccharide (LPS) stimulation, astrocytes released shedding vesicles (SVs) that enhanced vulnerability of dopaminergic neurons to neurotoxin. Further investigation showed that increased astrocytic miR-34a in SVs was involved in this progress via targeting anti-apoptotic protein Bcl-2 in dopaminergic neurons. We also found that inhibition of astrocytic miR-34a after LPS stimulation can postpone dopaminergic neuron loss under neurotoxin stress. These data revealed a novel mechanism underlying astrocyte-neuron interaction in disease.
Animals ; Astrocytes ; cytology ; drug effects ; metabolism ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cell-Derived Microparticles ; metabolism ; Disease Models, Animal ; Dopaminergic Neurons ; drug effects ; pathology ; Down-Regulation ; drug effects ; Humans ; Lipopolysaccharides ; pharmacology ; MicroRNAs ; metabolism ; Neurotoxins ; toxicity ; Oxidopamine ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Stress, Physiological ; drug effects

OBJECTIVETo study the alterations of alpha-7 nicotinic receptor (nAChR) status in human brain tissues with Alzheimer's disease (AD) and mouse brain tissues with Swedish APP670/671 gene mutation, and to study the effect of beta-amyloid peptides (A-beta) on alpha-7 nAChR status in cultured astrocytes and neurons.

METHODSPostmortem brain tissues from patients with AD and mouse brain tissues with Swedish APP mutation were collected. The expression of alpha-7 nAChR on astrocytes and neurons was detected by immunohistochemistry (ABC method). The alpha-7 nAChR protein level was measured by Western blotting. On the other hand, cultured astrocytes and neurons were treated with different concentrations of A-beta 25 - 35. The alpha-7 nAChR protein level was then measured.

RESULTSIncreased number of astrocytes surrounding senile plaques was observed in AD brain tissues. In AD brain tissues, as compared to age-matched controls, alpha-7 nAChR protein level was increased in astrocytes, but decreased in neurons. High level of alpha-7 nAChR protein was also observed in mouse brain tissues with APP mutation. Exposure to A-beta 25 - 35 induced an increase (up to 38%) in alpha-7 nAChR protein level in astrocytes but a decrease (up to 32%) in neurons.

CONCLUSIONSDecrease in alpha-7 nAChR level in neurons may be related to the pathogenesis of AD, whereas an increased level of alpha-7 nAChR in astrocytes, as induced by excessive A-beta, may represent a compensatory neuroprotective response.

Aged ; Aged, 80 and over ; Alzheimer Disease ; genetics ; metabolism ; pathology ; Amyloid beta-Peptides ; chemistry ; genetics ; metabolism ; Animals ; Astrocytes ; cytology ; drug effects ; metabolism ; Brain ; metabolism ; pathology ; Cell Line, Tumor ; Cells, Cultured ; Glial Fibrillary Acidic Protein ; analysis ; Humans ; Immunoblotting ; Immunohistochemistry ; Male ; Mice ; Mutation ; Neurons ; cytology ; drug effects ; metabolism ; Peptide Fragments ; pharmacology ; Receptors, Nicotinic ; biosynthesis

Human central neurocytoma is a kind of the brain tumors that are usually found in anterior part of the lateral ventricles. In this study, we established conditions that allowed proliferation of neurocytoma cells culture and analyzed characteristics of neurocytoma cells in vitro. For in vitro, a condition that used for culturing neural stem cells and contained basic fibroblast growth factor (bFGF) provided high proliferation. RT-PCR analaysis showed that nestin was found in neurocytoma cells, indicating that the neurocytomas possess neural stem cell properties. Interestingly, treatment of neurocytoma cells with forskolin increased expression of glial fibrillary acidic protein with a concomitant decrease in the nestin expression. Forskolin also induced morphological changes of neurocytoma cells to adopt an astrocyte-like phenotype. The results suggest that neurocyotma cells may have properties of multipotent neural stem cells.
Animals ; Astrocytes/cytology/*physiology ; Cell Differentiation/*drug effects ; Cell Proliferation ; Cell Shape ; Fibroblast Growth Factor 2/pharmacology ; Forskolin/*pharmacology/*therapeutic use ; Humans ; Intermediate Filament Proteins/metabolism ; Nerve Tissue Proteins/metabolism ; Neurocytoma/*drug therapy/pathology ; Research Support, Non-U.S. Gov't ; Tumor Cells, Cultured