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BioMed Research International
Volume 2013 (2013), Article ID 868742, 6 pages
http://dx.doi.org/10.1155/2013/868742
Research Article

Chronic Stress Induces Structural Alterations in Splenic Lymphoid Tissue That Are Associated with Changes in Corticosterone Levels in Wistar-Kyoto Rats

1Laboratorio de Psicoinmunología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente, 14370 Tlalpan, DF, Mexico
2Laboratorio de Farmacología Conductual, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente, 14370 Tlalpan, DF, Mexico
3Department of Neuropathology, National Institute of Neurology and Neurosurgery, 14269 Mexico City, DF, Mexico
4Departamento de Inmunología, Instituto Nacional de Cardiología, 14080 México, DF, Mexico
5Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 70228 México, DF, Mexico
6Departamento de Inmunología de la Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340 México, DF, Mexico
7Departamento de Investigación Experimental y Bioterio, Instituto Nacional de Ciencias Médicas y Nutrición, 14000 México, DF, Mexico
8Laboratory of Surgical Pathology, The American British Cowdray Medical Center, 01120 Mexico City, DF, Mexico

Received 25 November 2012; Accepted 2 January 2013

Academic Editor: George E. Plopper

Copyright © 2013 María Eugenia Hernandez et al. This 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.

Abstract

Major depressive disorder patients present chronic stress and decreased immunity. The Wistar-Kyoto rat (WKY) is a strain in which the hypothalamic-pituitary-adrenal axis is overactivated. To determine whether chronic stress induces changes in corticosterone levels and splenic lymphoid tissue, 9-week-old male rats were subject to restraint stress (3 h daily), chemical stress (hydrocortisone treatment, 50 mg/Kg weight), mixed stress (restraint plus hydrocortisone), or control treatment (without stress) for 1, 4, and 7 weeks. The serum corticosterone levels by RIA and spleens morphology were analyzed. Corticosterone levels as did the structure, size of the follicles and morphology of the parenchyma (increase in red pulp) in the spleen, varied depending on time and type of stressor. These changes indicate that chronic stress alters the immune response in the spleen in WKY rats by inducing morphological changes, explaining in part the impaired immunity that develops in organisms that are exposed to chronic stress.