Research Article
Deletion of Ovarian Hormones Induces a Sickness Behavior in
Rats Comparable to the Effect of Lipopolysaccharide
Hamid Azizi-Malekabadi,
1
Mahmoud Hosseini,
2,3
Masoume Pourganji,
3
Hoda Zabihi,
4
Mohsen Saeedjalali,
5
and Akbar Anaeigoudari
2,3
1
Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Isfahan (Khorasgan) Branch, Isfahan, Iran
2
Neurocognitive Research Center and Department of Physiology, School of Medicine, Mashhad University of Medical Sciences,
Azadi Square, Mashhad 9177947564, Iran
3
Neurogenic Inflammation Research Center and Department of Physiology, School of Medicine,
Mashhad University of Medical Sciences, Mashhad, Iran
4
Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
5
Mashhad Technical Faculty, Technical and Vocational University, Mashhad, Iran
Correspondence should be addressed to Mahmoud Hosseini; hosseinim@mums.ac.ir
Received 24 September 2014; Revised 26 December 2014; Accepted 5 January 2015
Academic Editor: Changiz Geula
Copyright © 2015 Hamid Azizi-Malekabadi et al. is is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
Neuroimmune factors have been proposed as the contributors to the pathogenesis of sickness behaviors. e effects of female
gonadal hormones on both neuroinflammation and depression have also been well considered. In the present study, the capability
of deletion of ovarian hormones to induce sickness-like behaviors in rats was compared with the effect lipopolysaccharide (LPS).
e groups were including Sham, OVX, Sham-LPS, and OVX-LPS. e Sham-LPS and OVX-LPS groups were treated with LPS
(250 g/kg) two hours before conducting the behavioral tests. In the forced swimming (FST), the immobility times in both OVX
and Sham-LPS groups were higher than that of Sham ( < 0.001). In open-field (OP) test, the central crossing number by OVX
and Sham-LPS groups were lower than Sham ( < 0.001) while there were no significant differences between OVX-LPS and OVX
groups. In elevated plus maze (EPM), the percent of entries to the open arm by both OVX and Sham-LPS groups was lower than
that of Sham group ( < 0.001). e results of present study showed that deletion of ovarian hormones induced sickness behaviors
in rats which were comparable to the effects of LPS. Moreover, further investigations are required in order to better understand the
mechanism(s) involved.
1. Introduction
Sickness behavior is a behavioral pattern that occurs fol-
lowing the infections and tissue injury in many mam-
malian species [1]. e behavioral features are including
malaise, hyperalgesia, pyrexia, disinterest in social inter-
actions, lethargy, behavioral inhibition, reduced locomotor
activity, lower exploration and grooming behaviors, reduc-
tion of reproductive performance, anhedonia, somnolence
and sleepiness, anorexia and weight loss, failure to con-
centrate, and anxiety [1]. Proinflammatory cytokines, such
as interleukin-1 (IL-1), tumor necrosis factor (TNF-), and
interleukin-6 (IL-6), can induce sickness behavior [2]. Proin-
flammatory cytokines can block the energy consuming pro-
cesses including locomotor, neurocognitive, and reproduc-
tive activities [3]. Depression, the second most common
chronic disease, is expanding in the world while about half
of the patients with depression are unaware of their disease
or their disease are diagnosed else [4]. Depression occurs in
children, adolescents, adults, and the elderly as a result of
the combination of states of sadness, loneliness, irritability,
absurdity, despair, confusion, and shame and the physical
symptoms, for example, reduction of locomotor activity [4].
In addition, depressed patients show the symptoms such as,
Hindawi Publishing Corporation
Neurology Research International
Volume 2015, Article ID 627642, 11 pages
http://dx.doi.org/10.1155/2015/627642