Elsevier

Neuroscience Research

Volume 39, Issue 4, April 2001, Pages 401-412
Neuroscience Research

Oligodendroglial cell death with DNA fragmentation in the white matter under chronic cerebral hypoperfusion: comparison between normotensive and spontaneously hypertensive rats

https://doi.org/10.1016/S0168-0102(01)00195-XGet rights and content

Abstract

We investigated the neuropathological and biochemical changes in the white matter of normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) after bilateral carotid artery ligation (BCAL). One week after BCAL, both WKY and SHR showed white matter rarefaction and vacuolation with reduced oligodendrocytes, but there was no difference between WKY and SHR. On the other hand, vacuoles formed by oligodendroglial cell death were increased significantly from 2 to 4 weeks in the optic tract and fimbria fornix of hypoperfused SHR. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP in situ nick end labeling (TUNEL)-positive cells and lectin-positive microglia increased in number and intensities of staining more markedly in SHR than in WKY. In situ cell death detection ELISA supported these results quantitatively. RT–PCR represented the expression of TNF-α, TNF receptor 1 (p55), caspase-2 (Ich-1) and -3 (CPP32) mRNAs in both WKY and SHR brains after BCAL. Immunohistochemical analyses revealed that TNF-α, TNF receptor 1 (p55), Ich-1 and CPP32 immunoreactive cells could also be detected in the white matter regions of hypoperfused SHR. These results suggested that local production of TNF-α by the activated microglia might selectively induce oligodendroglial cell death through the death domain-containing TNF receptor 1 (p55), caspase-2 or -3 activation, resulting in white matter changes as a primary pathological feature.

Introduction

Cerebral white matter lesions in various neuropathological conditions have become widespread by the recent advance in neuroradiologic diagnostic techniques, such as computerized tomography or magnetic resonance imaging (Pantoni and Garcia, 1997, Englund, 1998). Binswanger's disease is one of these neurological disorders and is characterized pathologically by lesions of subcortical white matter with severe atheromatosis of the arteries, enlarged ventricles and normal cortex (Jellinger and Neumayer, 1964, Roman, 1987). This disease is also characterized clinically by the presence of hypertension that is one of the risk factors of vascular dementia and ischemic white matter lesions (Skoog, 1998, de Leeuw et al., 1999). Although these subcortical white matter lesions may result from primary myelinopathy, or from axonopathy including Wallerian degeneration, or from oligodendropathy (Yamanouchi, 1991, Akiguchi et al., 1997), the exact mechanism of Binswanger's disease remains to be known. Recently, many reports demonstrated that oligodendrocytes might possibly be sensitive and vulnerable to ischemia or hypoperfusion in the cerebral white matter (Pantoni et al., 1996, Irving et al., 1997, Petito et al., 1998), and that it could be one of the pathogenic factors for the diffuse white matter changes in Binswanger's disease. Chronic cerebral hypoperfusion is likely to be diffuse white matter lesions (Kawamura et al., 1991). In fact, experimental white matter lesions have been reported to occur in normal young animals, such as rat (Wakita et al., 1994, Wakita et al., 1995), gerbil (Hattori et al., 1992, Kudo et al., 1990), and dog (Yoshioka et al., 1994), after bilateral common carotid artery occlusion. However, no report about the relationship between ischemic white matter changes and vascular risk factors such as hypertension has been published so far. In the present study, using normotensive and spontaneously hypertensive rats, we investigated the effect of hypertension on white matter lesions after bilateral common carotid artery ligation (BCAL). In addition, we also examine the mechanisms of white matter changes including apoptosis-like oligodendroglial cell death in both normotensive and spontaneously hypertensive rats after BCAL.

Section snippets

Animal preparation

Male 20-week-old Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were used (Charles River Japan, Yokohama, Japan). Experiments were carried out following the NIH guidelines for the care and use of laboratory animals, and approved by the local ethics committees of the BF Research Institute. All animals were maintained under specific pathogen-free conditions and fed regular rat chow (CE-2, Clea Japan, Tokyo, Japan) and tap water ad libitum. Arterial blood pressure was measured by a

Blood pressure

Average values of mean arterial blood pressure (MABP) of WKY and SHR at various time intervals following BCAL and their normal controls are summarized in Table 1. At 1 week after BCAL, MABP of both WKY and SHR rose significantly compared to those of the controls, and maintained higher levels than those in the controls of each strain for at least 4 weeks.

Standard histological and immunohistochemical findings

Three days after BCAL, the GFAP-positive astrocytes and lectin-positive microglia were more frequent than in sham-operated animals in the white

Discussion

In the present study, we demonstrated that after BCAL, spontaneous hypertension might accelerate white matter lesions with vacuolation, microglial activation and oligodendroglial DNA fragmentation after BCAL. Furthermore, to the best of our knowledge, there is no previous study that compares white matter rarefaction between WKY and SHR instead of the cerebral infarction (Ogata et al., 1976).

Because of the lack of apparent DNA fragmentation in the normal controls, the development of

References (57)

  • I Akiguchi et al.

    Alterations in glia and axons in the brains of Binswanger's disease patient

    Stroke

    (1997)
  • N.B Bhat et al.

    Hydrogen peroxide activation of multiple mitogen-activated protein kinases in an oligodendrocyte cell line: role of extracellular signal-regulated kinase in hydrogen peroxide-induced cell death

    J. Neurochem.

    (1999)
  • R.V Bhat et al.

    Expression of the APC tumor suppressor protein in oligodendroglia

    Glia

    (1996)
  • B Bonetti et al.

    Multiple sclerosis: oligodendrocytes display cell death-related molecules in situ but do not undergo apoptosis

    Ann. Neurol.

    (1997)
  • P Casaccia-Bonnefil

    Cell death in the oligodendrocyte lineage: a molecular perspective of life/death decisions in development and disease

    Glia

    (2000)
  • C Charriaut-Marlangue et al.

    A cautionary note on the use of the TUNEL stain to determine apoptosis

    NeuroReport

    (1995)
  • C Charriaut-Marlangue et al.

    Apoptosis and necrosis after reversible focal ischemia: an in situ DNA fragmentation analysis

    J. Cereb. Blood Flow Metab.

    (1996)
  • M.J Crowe et al.

    Apoptosis and delayed degeneration after spinal cord injury in rats and monkeys

    Nat. Med.

    (1997)
  • F.-E de Leeuw et al.

    A follow-up study of blood pressure and cerebral white matter lesions

    Ann. Neurol.

    (1999)
  • S.D D'Souza et al.

    Multiple sclerosis: Fas signaling in oligodendrocyte cell death

    J. Exp. Med.

    (1996)
  • E Englund

    Neuropathology of white matter changes in Alzheimer's disease and vascular dementia

    Dement. Geriatr. Cogn. Disord.

    (1998)
  • I Ferrer et al.

    Differential c-Fos and caspase expression following kainic acid excitotoxicity

    Acta Neuropathol.

    (2000)
  • M Fujishima et al.

    Change in local cerebral blood flow following bilateral carotid occlusion in spontaneously hypertensive and normotensive rats

    Stroke

    (1981)
  • Y Gavrieli et al.

    Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation

    J. Cell Biol.

    (1992)
  • R Gold et al.

    Differentiation between cellular apoptosis and necrosis by combined use of in situ tailing and nick translation techniques

    Lab. Invest.

    (1994)
  • C Gu et al.

    Oligodendrocyte apoptosis mediated by caspase activation

    J. Neurosci.

    (1999)
  • H Hattori et al.

    Cumulative white matter changes in the gerbil brain under chronic cerebral hypoperfusion

    Acta Neuropathol.

    (1992)
  • S Hisahara et al.

    ICE/CED-3 family executes oligodendrocyte apoptosis by tumor necrosis factor

    J. Neurochem.

    (1997)
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