quetiapine-fumarate and Demyelinating-Diseases

White matter disturbances and myelin impairment are key features of schizophrenia. The antipsychotic drug quetiapine can promote the maturation of oligodendrocytes, but the molecular mechanisms remain largely unknown.. The schizophrenia-like behaviors, degrees of demyelination, and levels of Notch signaling molecules in forebrains of adult male C57BL/6 mice were examined after fed with cuprizone (0.2% wt/wt) in the presence or absence of 10mg/kg/d quetiapine for 6 weeks. These parameters were also observed after the transcranial injection of Notch signaling inhibitor MW167 (1mM) daily during the last week of the treatment period.. Quetiapine ameliorated the schizophrenia-like behaviors and decreased expression of myelin basic protein and inhibition of Notch signaling molecules, such as Notch1, Hes1, and Hes5, in the forebrain that induced by cuprizone. These beneficial effects of quetiapine were abolished by MW167.. The antipsychotic and myelin protective effects of quetiapine are mediated by Notch signaling in a mouse model of cuprizone-induced demyelination associated with schizophrenia-like behaviors. The Notch pathway might therefore be a novel target for the development of antipsychotic drugs.

Topics: Animals; Cuprizone; Demyelinating Diseases; Injections, Intraventricular; Male; Mice; Mice, Inbred C57BL; Myelin Sheath; Neuroprotective Agents; Peptides; Quetiapine Fumarate; Receptors, Notch; Schizophrenia; Signal Transduction

Cuprizone is a copper-chelating agent and able to induce oligodendrocyte loss and demyelination in C57BL/6 mouse brain. Recent studies have used the cuprizone-fed mouse as an animal model of schizophrenia to examine putative roles of altered oligodendrocytes in this mental disorder. The present study reported the effects of cuprizone on the brain metabolites and oxidative parameters with the aim of providing neurochemical evidence for the application of the cuprizone mouse as an animal model of schizophrenia. In addition, we examined effects of quetiapine on the cuprizone-induced changes in brain metabolites and oxidative parameters; this atypical antipsychotic was shown to ameliorate the cuprizone-induced demyelination and behavioral changes in previous studies. C57BL/6 mice were fed a standard rodent chow without or with cuprizone (0.2% w/w) for four weeks during which period they were given sterilized saline or quetiapine in saline. The results of the proton magnetic resonance spectroscopy (1H-MRS) showed that cuprizone-feeding decreased (1)H-MRS signals of N-acetyl-l-aspartate (NAA), total NAA (NAA + NAAG), and choline-containing compounds (phosphorylcholine and glycerophosphorylcholine), suggestive of mitochondrial dysfunction in brain neurons. Biochemical analyses showed lower activities of catalase and glutathione peroxidase, but higher levels of malondialdehyde and H2O2 in the brain tissue of cuprizone-fed mice, indicative of an oxidative stress. These cuprizone-induced changes were effectively relieved in the mice co-administered with cuprizone and quetiapine, although the antipsychotic alone showed no effect. These findings suggest the toxic effects of cuprizone on mitochondria and an antioxidant capacity of quetiapine, by which this antipsychotic relieves the cuprizone-induced mitochondrial dysfunction in brain cells.

Topics: Animals; Antipsychotic Agents; Brain; Chelating Agents; Cuprizone; Demyelinating Diseases; Disease Models, Animal; Hydrogen Peroxide; Male; Mice, Inbred C57BL; Neurons; Oligodendroglia; Quetiapine Fumarate

Several neuroimaging studies have revealed that the brains of schizophrenic patients exhibit abnormalities in white matter pathways. Using magnetic resonance imaging (MRI) methods, such as T2-weighted imaging and diffusion tensor imaging (DTI), it is possible to objectively quantify white matter structural properties in patients as well as the pharmacological effect on white matter. In the preclinical domain, these strategies, however, have been hindered by a lack of in vivo imaging assays. One preclinical approach that has been used to pharmacologically challenge the integrity of the white matter is the chronic administration of the copper chelator, cuprizone. In the present study, C57BL/6 mice were given 0.2% cuprizone in their diet for five weeks with or without the antipsychotic drug, quetiapine (10 mg/kg). In accordance with previous studies, myelin breakdown in cuprizone-exposed mice was measured by using T2-weighted MRI and DTI. Here, we demonstrate that cuprizone-induced white matter changes were attenuated by quetiapine treatment. These MRI-based results and trends were confirmed by histological and immunohistochemistry measures. This study suggests that the cuprizone-exposed C57BL/6 mouse is a potential animal model to investigate the impact of treatments on white matter abnormalities in schizophrenia.

Topics: Animals; Antipsychotic Agents; Chelating Agents; Cuprizone; Data Interpretation, Statistical; Demyelinating Diseases; Dibenzothiazepines; Diffusion Tensor Imaging; Image Processing, Computer-Assisted; Immunohistochemistry; Magnetic Resonance Imaging; Mice; Mice, Inbred C57BL; Phenotype; Quetiapine Fumarate

Myelin and oligodendrocyte dysfunctions have been consistently found in patients with schizophrenia. The effect of antipsychotics on myelin disturbances is unknown. The present study examined the effects of quetiapine on oligodendrocyte regeneration and myelin repair in a demyelination animal model. C57BL/6 mice were fed with cuprizone (0.2% w/w) for 12 weeks to induce chronic demyelination and oligodendrocyte degeneration, after which cuprizone was withdrawn to allow recovery. Quetiapine (10mg/kg/day) or vehicle (water) was administrated orally to mice for 0, 2, 3, or 4 weeks after cuprizone withdrawal. Locomotor activity and Y-maze tests were used to evaluate behavioral changes in the mice. Immunohistochemical staining was used to detect morphological and biological changes in the brains. Cuprizone administration for 12 weeks resulted in severe demyelination, locomotor hyperactivity, and working memory impairment in mice. Remyelination occurred when cuprizone was withdrawn. Quetiapine treatment during the recovery period significantly improved the spatial working memory and increased myelin restoration. Quetiapine treatment also enhanced the repopulation of mature oligodendrocytes in the demyelinated lesions, which was associated with down-regulation of transcription factor olig2 in the process of cell maturation. The results of this study demonstrated that quetiapine treatment during the recovery period improves spatial working memory and promotes oligodendrocyte development and remyelination. This study supports the role of oligodendrocyte dysfunction in memory deficits in a schizophrenia mouse model and suggests that quetiapine may target oligodendrocytes and improve cognitive function.

Topics: Animals; Antipsychotic Agents; Chelating Agents; Cuprizone; Demyelinating Diseases; Dibenzothiazepines; Disease Models, Animal; Memory, Short-Term; Mice; Mice, Inbred C57BL; Motor Activity; Myelin Sheath; Oligodendroglia; Quetiapine Fumarate; Regeneration; Schizophrenia

Recent human studies employing new magnetic resonance imaging techniques and micro-array analyses feature schizophrenia as a brain disease with alterations in white matter (WM), which is mainly composed of oligodendrocytes (OLs) and their processes wrapping around neuronal axons. To examine the putative role of OLs in the pathophysiology and treatment of schizophrenia, animal studies are essential. In the present study, C57BL/6 mice were given 0.2% cuprizone (CPZ) in their diet for five weeks during which they drank distilled water without or with quetiapine (QTP, 10 mg/kg). The mice fed with normal chow were used as controls. CPZ is a copper chelator and has been reported to induce consistent demyelination in the brain of C57BL/6 mouse by specifically damaging OLs. QTP is an atypical antipsychotic widely used in the treatment of schizophrenia and other psychotic disorders. In accordance with previous studies, CPZ-exposed mice showed pervasive myelin breakdown and demyelination. The amount of myelin basic protein (MBP) in the cerebral cortex was decreased by CPZ-exposure as shown in Western-blot analysis. In addition, the demyelinated sites were teemed with activated microglia and astrocytes but a few myelin forming OLs. Moreover, the activity of copper-zinc superoxide dismutase decreased in the cerebral cortex of CPZ-exposed mice. However, all of these pathological changes in WM were either prevented or alleviated in CPZ-exposed mice co-administered with QTP. These results suggest that the CPZ-exposed C57BL/6 mouse is a potential animal model to study possible roles of OLs in the pathogenesis and treatment of schizophrenia.

Topics: Animals; Antipsychotic Agents; Astrocytes; Blotting, Western; Brain; Brain Diseases; Chelating Agents; Cuprizone; Demyelinating Diseases; Dibenzothiazepines; Disease Models, Animal; Mice; Mice, Inbred C57BL; Microglia; Oligodendroglia; Quetiapine Fumarate