The EAE-associated behavioral syndrome: II. Modulation by anti-inflammatory treatments

doi:10.1016/S0165-5728(03)00073-0

Journal of Neuroimmunology

Volume 137, Issues 1–2, April 2003, Pages 100-108

https://doi.org/10.1016/S0165-5728(03)00073-0 Get rights and content

Abstract

EAE is associated with sickness behavior symptoms that are temporally correlated with inflammatory processes. To further elucidate the role of inflammatory mediators in the behavioral syndrome, EAE mice were injected daily with anti-inflammatory drugs, beginning at disease onset. Dexamethasone or interleukin-1 (IL-1) receptor antagonist or the prostaglandins synthesis inhibitor indomethacin attenuated the behavioral symptoms. Administration of the tumor necrosis-factor α (TNF-α) synthesis inhibitor pentoxifylline or targeted deletion of the type I TNF receptor had no behavioral effects whereas administration of pentoxifylline in IL-1ra-treated mice further reversed the behavioral depression. These findings demonstrate the critical involvement of pro-inflammatory cytokines and prostaglandins in the EAE-associated behavioral syndrome, and may have implications for understanding and treating the neuropsychiatric disturbances in multiple sclerosis (MS) patients.

Introduction

EAE is an autoimmune disease of the central nervous system (CNS), in which CD4 Th1 cells are activated against self-myelin proteins and insult the myelin sheaths within the brain and spinal cord. This insult results in ascending motor and sensory deficits. The clinical episodes of EAE are associated with a behavioral syndrome consisting of anorexia and loss of body weight, reduced consumption of a sweet solution and decreased social investigation (Pollak et al., 2000). These behavioral alterations were termed EAE-associated behavioral syndrome or EBS (Pollak et al., 2002). Previous research revealed a correlation in time between phases of the EBS and the expression of the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis-factor α (TNF-α). Other EAE-related phenomena corresponded only partially to the behavioral phases, e.g., motor impairment began 1–2 days after the initiation of the behavioral alterations and sustained for several days after the behavioral recovery; onset of infiltration into the brain and of the increase in prostaglandin E₂ (PGE₂) production within several brain areas coincided with the onset of the behavioral syndrome, but both continued following behavioral recovery (Pollak et al., in this issue).

Sickness behavior is a common phenomenon accompanying infectious and inflammatory diseases, as demonstrated in animals and in humans by administration of lipopolysaccharide (LPS), Mycoplasma fermentans, HIV-gp120, influenza virus, as well as many other pathogens and toxins Kozak et al., 1997, Szechtman et al., 1997, Swiergiel et al., 1997, Connor and Leonard, 1998, Maier and Watkins, 1998, Yirmiya et al., 1999a, Yirmiya et al., 1999b, Dantzer, 2001, Barak et al., 2002. Pro-inflammatory mediators in general, and IL-1, TNF-α and PGE₂ in particular, were implicated as mechanisms mediating sickness behavior in several models Connor and Leonard, 1998, Maier and Watkins, 1998, Yirmiya et al., 1999b, Yirmiya et al., 2000, Dantzer, 2001, Larson and Dunn, 2001. The aim of the present study was to further establish the role for these inflammatory mediators in the behavioral alterations associated with EAE. To this aim, we examined the EBS in mice that were treated with the steroid anti-inflammatory drug dexamethasone, which attenuates cytokine production (Barnes and Adcock, 1993), as well as more specific inhibitors of IL-1, TNF-α and PGE₂, including IL-1 receptor antagonist (IL-1ra) which blocks the effects of IL-1 (Dinarello, 2000), pentoxifylline, which blocks the synthesis of TNF-α (Windmeier and Gressner, 1997), and indomethacin, which blocks the synthesis of prostaglandins from arachidonic acid by inhibiting cyclooxygenase (COX) (Lupulescu, 1996).

The most popular model of sickness behavior is the one induced by administration of LPS, the active component of gram-negative bacteria cell wall. Using this model, a role for pro-inflammatory cytokines and prostaglandins in mediating sickness behavior was established Connor and Leonard, 1998, Maier and Watkins, 1998, Yirmiya et al., 1999b, Dantzer, 2001, Larson and Dunn, 2001, Reichenberg et al., 2001. To enable a comparison between different models of sickness behavior, the protocols used to manipulate cytokine actions in EBS were subsequently examined in LPS-treated mice.

Section snippets

Subjects

Subjects were female SJL/J or C57Bl/6 mice (Harlan–Sprague–Dawley, USA), or C57Bl/6 mice with targeted deletion of the p55 TNF receptor gene (TNFR1−/−) (Jackson Laboratories). Mice (7–12/group) were 8–12 weeks in age. Animals were housed individually in constant room temperature (23±1 °C), and were provided with food, water and 2% sucrose solution ad libitum. Treatments and measurements were conducted during the dark phase of a reversed 12 h light–dark cycle (lights off at 8:30 AM).

Active induction and clinical evaluation of EAE

In most of

Effect of dexamethasone on the EBS

The effects of dexamethasone on the neurological score and the EBS were tested during 2 days of treatment (the day of disease onset and the following day). Dexamethasone produced a mild reduction in neurological score, which did not reach statistical significance (F(1,15)=1.57, p>0.05) (Fig. 1A). EAE-associated decrease in body weight was also not affected by dexamethasone (F(1,15)=3.18, p>0.05) (Fig. 1B).

EAE was associated with decreased food intake, which was significantly attenuated by the

Discussion

The results of the present study corroborate our previous report that EAE is associated with a behavioral syndrome, consisting of a reduction in food and sucrose intake and in social exploration (Pollak et al., 2000). Furthermore, using pharmacological treatments, we demonstrated here the critical role of inflammatory processes in mediating specific aspects of the EBS. Administration of PGE₂ synthesis inhibitor or IL-1ra attenuated the several aspects of the behavioral syndrome.

Acknowledgments

The authors thank Orli Bar-Shalev, Shira Gur, Lior Friedman, Yael Perets, Meital Shahar, Michal Shlayer, Michal Shuker, and Gili Wolf for their excellent help in running the experiments. The research was supported by a grant from the Israel Science Foundation (No. 820/00) and in part by the Lena P. Harvey Endowment Fund for Neurological Research. RY is a member of the Eric Roland Center for Neurodegenerative Diseases at the Hebrew University of Jerusalem.

References (44)

V. Badovinac et al.
Interleukin-1 receptor antagonist suppresses experimental autoimmune encephalomyelitis (EAE) in rats by influencing the activation and proliferation of encephalitogenic cells
J. Neuroimmunol.
(1998)
B. Bannwarth et al.
Clinical pharmacokinetics of nonsteroidal anti-inflammatory drugs in the cerebrospinal fluid
Biomed. Pharmacother.
(1989)
O. Barak et al.
Involvement of brain cytokines in the neurobehavioral disturbances induced by HIV-1 glycoprotein 120
Brain Res.
(2002)
P.J. Barnes et al.
Anti-inflammatory actions of steroids: molecular mechanisms
Trends Pharmacol. Sci.
(1993)
R.M. Bluthe et al.
Central mediation of the effects of interleukin-1 on social exploration and body weight in mice
Psychoneuroendocrinology
(1997)
T.J. Connor et al.
Depression, stress and immunological activation: the role of cytokines in depressive disorders
Life Sci.
(1998)
R. Dantzer
Cytokine-induced sickness behavior: where do we stand?
Brain Behav. Immun.
(2001)
E.G. Gutierrez et al.
Blood-borne interleukin-1 receptor antagonist crosses the blood–brain barrier
J. Neuroimmunol.
(1994)
S.J. Larson et al.
Behavioral effects of cytokines
Brain Behav. Immun.
(2001)
A. Lupulescu
Prostaglandins, their inhibitors and cancer
Prostaglandins Leukot. Essent. Fat. Acids
(1996)

D. Martin et al.

Protective effect of the interleukin-1 receptor antagonist (IL-1ra) on experimental allergic encephalomyelitis in rats

J. Neuroimmunol.

(1995)

I. Matous-Malbohan et al.

Experimental allergic encephalomyelitis. The effect of dexamethasone on growth and proliferation in the draining lymph node

Exp. Pathol.

(1976)

C. Paul et al.

The detection and quantification of inflammation in the central nervous system during experimental allergic encephalomyelitis using the radiopharmaceutical 99mTc-RP128

J. Neurosci. Methods

(2000)

Y. Pollak et al.

Behavioral aspects of autoimmune encephalomyelitis

J. Neuroimmunol.

(2000)

Y. Pollak et al.

Experimental autoimmune encephalomyelitis (EAE)-associated behavioral syndrome as a model of ‘depression due to multiple sclerosis’

Brain Behav. Immun.

(2002)

J. Schiffenbauer et al.

The induction of EAE is only partially dependent on TNF receptor signaling but requires IL-1 type I receptor

Clin. Immunol.

(2000)

E. Shohami et al.

Cytokine production in the brain following closed brain injury: dexanabinol (HU-211) is a novel TNF-α inhibitor and an effective neuroprotectant

J. Neuroimmunol.

(1997)

L. Steinman

Assessment of animal models for MS and demyelinating disease in the design of rational therapy

Neuron

(1999)

A.H. Swiergiel et al.

The role of IL-1, IL-6 and TNFα in the feeding responses to endotoxin and influenza virus infection in mice

Brain Behav. Immun.

(1999)

A.H. Swiergiel et al.

The role of cytokines in the behavioral responses to endotoxin and influenza virus infection in mice: effects of acute and chronic administration of the interleukin-1 receptor antagonist (IL-1ra)

Brain Res.

(1997)

J. Weidenfeld et al.

Inhibition of prostaglandin synthesis in brain of rat by dexamethasone: lack of effect of dexamethasone phosphate ester and various hormonal steroids

Neuropharmacology

(1988)

C. Windmeier et al.

Pharmacological aspects of pentoxifylline with emphasis on its inhibitory actions on hepatic fibrogenesis

Gen. Pharmacol.

(1997)

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The EAE-associated behavioral syndrome: II. Modulation by anti-inflammatory treatments

Abstract

Introduction

Section snippets

Subjects

Active induction and clinical evaluation of EAE

Effect of dexamethasone on the EBS

Discussion

Acknowledgments

J. Neuroimmunol.

Biomed. Pharmacother.

Brain Res.

Trends Pharmacol. Sci.

Psychoneuroendocrinology

Life Sci.

Brain Behav. Immun.

J. Neuroimmunol.

Brain Behav. Immun.

Prostaglandins Leukot. Essent. Fat. Acids

J. Neuroimmunol.

Exp. Pathol.

J. Neurosci. Methods

J. Neuroimmunol.

Brain Behav. Immun.

Clin. Immunol.

J. Neuroimmunol.

Neuron

Brain Behav. Immun.

Brain Res.

Neuropharmacology

Gen. Pharmacol.