Regional differences between grey and white matter in cuprizone induced demyelination

doi:10.1016/j.brainres.2009.06.005

Brain Research

Volume 1283, 4 August 2009, Pages 127-138

https://doi.org/10.1016/j.brainres.2009.06.005 Get rights and content

Abstract

Cuprizone feeding is a commonly used model to study experimental de- and remyelination, with the corpus callosum being the most frequently investigated white matter tract. We have previously shown that demyelination is also extensive in the cerebral cortex in the cuprizone model. In the current study, we have performed a detailed analysis of the dynamics of demyelination in the cortex in comparison to the corpus callosum. Prominent and almost complete demyelination in the corpus callosum was observed after 4.5–5 weeks of 0.2% cuprizone feeding, whereas complete cortical demyelination was only observed after 6 weeks of cuprizone feeding. Interestingly, remyelination in the corpus callosum occurred even before the termination of cuprizone administration. Accumulation of microglia in the corpus callosum started as early as week 3 reaching its maximum at week 4.5 and was still significantly elevated at week 6 of cuprizone treatment. Within the cortex only a few scattered activated microglial cells were found. Furthermore, the intensity of astrogliosis, accumulation of oligodendrocyte progenitor cells and nestin positive cells differed between the two areas investigated. The time course and dynamics of demyelination differ in the corpus callosum and in the cortex, suggesting different underlying pathomechanisms.

Introduction

Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system (CNS), characterised by demyelinating white matter lesions, glial scar formation, and axonal loss. In recent years studies have shown that demyelination and neuronal damage also affect the cerebral cortex. The underlying pathophysiological mechanisms seem to differ between white and grey matter since cortical demyelinating lesions are associated with an intact blood brain barrier, alleviated infiltration of lymphocytes and mild astrogliosis (Bo et al., 2003, van Horssen et al., 2007). Furthermore, the remyelinating capacity of grey matter lesions seemed to be higher compared to white matter lesions (Albert et al., 2007).

However, the detailed pathomechanisms of grey and white matter demyelination and subsequent remyelination are still only poorly understood. To address these questions animal models like the commonly used murine cuprizone model are valuable. In this model, young adult mice are fed with the copper chelator cuprizone (bis-cyclohexanone oxaldihydrazone) leading to reproducible demyelination of the corpus callosum within weeks (Matsushima and Morell, 2001, Torkildsen et al., 2008). Previously, we have shown that cuprizone administration also causes demyelination of the cerebral cortex with subsequent remyelination after withdrawal of the toxin (Skripuletz et al., 2008).

In order to understand the mechanisms of white and grey matter demyelination we compared the dynamics of cuprizone induced demyelination and glial reactions in the cortex and the corpus callosum in detail.

Section snippets

De- and remyelination follow a different pattern in the cortex and corpus callosum

To determine the sequential loss and re-expression of myelin proteins (PLP, MBP, CNPase and MOG) during cuprizone treatment histochemical and immunohistochemical stainings were performed. As depicted in Figs. 1B and C, PLP immunoreactivity in the cortex continuously decreased and reached the minimum at week 6 of the cuprizone treatment. The time course for MBP was nearly the same, except for week 6, where in some animals small amount of MBP was visible in the cortex (data not shown). As

Discussion

The cuprizone model of toxic demyelination in the CNS is widely used to study demyelinating and remyelinating processes in the white matter, namely the corpus callosum. It has recently been described that besides white matter tracts there is also extensive cortical demyelination and subsequent cortical remyelination after toxin withdrawal in this model (Skripuletz et al., 2008). Since it has been suggested that the mechanisms of de- and remyelination may differ between white and grey matter in

Conclusion

Here, we showed that in the murine cuprizone model the time course of demyelination in the corpus callosum and in the cerebral cortex differed remarkably. Demyelination in the cortex was delayed as compared to the corpus callosum. Detailed analysis of the cellular components during the demyelination process showed a much stronger cellular response in the corpus callosum as compared to the cortex. This observation suggests different patterns of tissue reactivity. This may also have implications

Animals and induction of demyelination

C57BL/6 male mice were obtained from Charles River (Sulzfeld, Germany). Animals underwent routine cage maintenance once a week and were microbiologically monitored according to the recommendations of the Federation of European Laboratory Animal Science Associations (Rehbinder et al., 1996). Food and water were available ad libitum. All research and animal care procedures were approved by the Review Board for the Care of Animal Subjects of the district government (Lower Saxony, Germany) and

Acknowledgments

We thank I. Cierpka-Leja for excellent technical assistance. This work has been supported by the Georg-Christoph-Lichtenberg Fellowship by the State of Lower Saxony and by Marie Curie Actions; grant number: MST-CT-2005 021014.

References (22)

LendahlU. et al.
CNS stem cells express a new class of intermediate filament protein
Cell
(1990)
LinR.C. et al.
Re-expression of the intermediate filament nestin in reactive astrocytes
Neurobiol. Dis.
(1995)
MasonJ.L. et al.
Oligodendrocytes and progenitors become progressively depleted within chronically demyelinated lesions
Am. J. Pathol.
(2004)
SkripuletzT. et al.
Cortical demyelination is prominent in the murine cuprizone model and is strain-dependent
Am. J. Pathol.
(2008)
YangH.J. et al.
Region-specific susceptibilities to cuprizone-induced lesions in the mouse forebrain: Implications for the pathophysiology of schizophrenia
Brain Res.
(2009)
AlbertM. et al.
Extensive cortical remyelination in patients with chronic multiple sclerosis
Brain Pathol.
(2007)
BaumannN. et al.
Biology of oligodendrocyte and myelin in the mammalian central nervous system
Physiol. Rev.
(2001)
BoL. et al.
Intracortical multiple sclerosis lesions are not associated with increased lymphocyte infiltration
Mult. Scler.
(2003)
BruckW. et al.
Monocyte/macrophage differentiation in early multiple sclerosis lesions
Ann. Neurol.
(1995)
BussA. et al.
Sequential loss of myelin proteins during Wallerian degeneration in the rat spinal cord
Glia
(2003)

KernieS.G. et al.

Brain remodeling due to neuronal and astrocytic proliferation after controlled cortical injury in mice

J. Neurosci. Res.

(2001)

Cited by (185)

Brain Stiffness Follows Cuprizone-Induced Variations in Local Myelin Content
2023, Acta Biomaterialia
Brain maturation and neurological diseases are intricately linked to microstructural changes that inherently affect the brain’s mechanical behavior. Animal models are frequently used to explore relative brain stiffness changes as a function of underlying microstructure. Here, we are using the cuprizone mouse model to study indentation-derived stiffness changes resulting from acute and chronic demyelination during a 15-week observation period. We focus on the corpus callosum, cingulum, and cortex which undergo different degrees of de- and remyelination and, therefore, result in region-specific stiffness changes. Mean stiffness of the corpus callosum starts at 1.1 $\pm$ 0.3 kPa in untreated mice, then cuprizone treatment causes stiffness to drop to 0.6 $\pm$ 0.1 kPa by week 3, temporarily increase to 0.9 $\pm$ 0.3 kPa by week 6, and ultimately stabilize around 0.7 $\pm$ 0.1 kPa by week 9 for the rest of the observation period. The cingulum starts at 3.2 $\pm$ 0.9 kPa, then drops to 1.6 $\pm$ 0.4 kPa by week 3, and then gradually stabilizes around 1.4 $\pm$ 0.3 kPa by week 9. Cortical stiffness exhibits less stiffness variations overall; it starts at 4.2 $\pm$ 1.3 kPa, drops to 2.4 $\pm$ 0.6 kPa by week 3, and stabilizes around 2.7 $\pm$ 0.9 kPa by week 6. We also assess the impact of tissue fixation on indentation-based mechanical tissue characterization. On the one hand, fixation drastically increases untreated mean tissue stiffness by a factor of 3.3 for the corpus callosum, 2.9 for the cingulum, and 3.6 for the cortex; on the other hand, fixation influences interregional stiffness ratios during demyelination, thus suggesting that fixation affects individual brain tissues differently. Lastly, we determine the spatial correlation between stiffness measurements and myelin density and observe a region-specific proportionality between myelin content and tissue stiffness.
Despite extensive work, the relationship between microstructure and mechanical behavior in the brain remains mostly unknown. Additionally, the existing variation of measurement results reported in literature requires in depth investigation of the impact of individual cell and protein populations on tissue stiffness and interregional stiffness ratios. Here, we used microindentation measurements to show that brain stiffness changes with myelin density in the cuprizone-based demyelination mouse model. Moreover, we explored the impact of tissue fixation prior to mechanical characterization because of conflicting results reported in literature. We observe that fixation has a distinctly different impact on our three regions of interest, thus causing region-specific tissue stiffening and, more importantly, changing interregional stiffness ratios.
β-hydroxybutyrate attenuates demyelination, modulates microglial phenotype and supports blood-brain barrier integrity in a cuprizone-induced mouse model of demyelination
2023, Journal of Functional Foods
β-hydroxybutyrate has been reported to have neuroprotective activity. In this study, the neuroprotective effects of BHB were investigated on a demyelination model, the cuprizone model. We found that BHB reduced demyelination, which was confirmed by western blot for myelin-oligodendrocyte glycoprotein (MOG) and myelin proteolipid protein (PLP). Following BHB treatment, the number of connexin43⁺ (Cx43⁺) + GFAP⁺ cells and Iba-1⁺ + CD16/32⁺ cells decreased, whereas the number of Cx47⁺ + oligo2⁺ cells and Iba-1⁺ + Arginase-1⁺ cells increased significantly. Furthermore, BHB significantly repressed the expression of MMP-9/12, and increased the expression of blood-brain barrier (BBB) markers (such as PECAM-1 and ZO-1) in CPZ mice. We report that BHB promotes M2 microglia polarization and ameliorates BBB dysfunction caused by downregulation of HDAC3, NF-κB, Aim2 and NLRP3, as well as upregulation of SIRT1 in CPZ mice. Thus, these findings suggest that BHB may be a therapeutic approach for preventing demyelinating diseases.
Transcriptomic atlas and interaction networks of brain cells in mouse CNS demyelination and remyelination
2023, Cell Reports
Demyelination is a hallmark of multiple sclerosis, leukoencephalopathies, cerebral vasculopathies, and several neurodegenerative diseases. The cuprizone mouse model is widely used to simulate demyelination and remyelination occurring in these diseases. Here, we present a high-resolution single-nucleus RNA sequencing (snRNA-seq) analysis of gene expression changes across all brain cells in this model. We define demyelination-associated oligodendrocytes (DOLs) and remyelination-associated MAFB^hi microglia, as well as astrocytes and vascular cells with signatures of altered metabolism, oxidative stress, and interferon response. Furthermore, snRNA-seq provides insights into how brain cell types connect and interact, defining complex circuitries that impact demyelination and remyelination. As an explicative example, perturbation of microglia caused by TREM2 deficiency indirectly impairs the induction of DOLs. Altogether, this study provides a rich resource for future studies investigating mechanisms underlying demyelinating diseases.
Immunofluorescence assay for demyelination, remyelination, and proliferation in an acute cuprizone mouse model
2023, STAR Protocols
Here, we present a protocol to assess demyelination in the corpus callosum of an acute cuprizone mouse model, which is routinely used to induce demyelination for studying myelin regeneration in the rodent brain. We describe the tracing of neural stem cells via intraperitoneal injection of tamoxifen into adult Gli1CreERT2;Ai9 mice and the induction of demyelination with cuprizone diet. We also detail EdU administration, cryosectioning of the mouse brain, EdU labeling, and immunofluorescence staining to examine proliferation and myelination.
For complete details on the use and execution of this protocol, please refer to Radecki et al. (2020).¹
Transient demyelination causes long-term cognitive impairment, myelin alteration and network synchrony defects
2024, GLIA
Automated analysis of gray matter damage in aged mice reveals impaired remyelination in the cuprizone model
2024, Brain Pathology

View all citing articles on Scopus

¹: Both authors contributed equally.

View full text

Research ReportRegional differences between grey and white matter in cuprizone induced demyelination

Abstract

Introduction

Section snippets

De- and remyelination follow a different pattern in the cortex and corpus callosum

Discussion

Conclusion

Animals and induction of demyelination

Acknowledgments

Cell

Neurobiol. Dis.

Am. J. Pathol.

Am. J. Pathol.

Brain Res.

Extensive cortical remyelination in patients with chronic multiple sclerosis

Brain Pathol.

Biology of oligodendrocyte and myelin in the mammalian central nervous system

Physiol. Rev.

Intracortical multiple sclerosis lesions are not associated with increased lymphocyte infiltration

Mult. Scler.

Monocyte/macrophage differentiation in early multiple sclerosis lesions

Ann. Neurol.

Sequential loss of myelin proteins during Wallerian degeneration in the rat spinal cord

Glia

Brain remodeling due to neuronal and astrocytic proliferation after controlled cortical injury in mice

J. Neurosci. Res.

Research Report
Regional differences between grey and white matter in cuprizone induced demyelination