Maternal separation during breastfeeding induces changes in the number of cells immunolabeled to GFAP.

Edwin Bautista,Zulma Dueñas

doi:10.3922/j.psns.2012.2.11

Abstract

mother-child relationship is fundamental to the establishment and maintenance of synaptic networks and physiological and emotional development. Animal models including maternal separation have been used to study changes at behavioral and neurobiochemical levels. Due to the relevance of glial cells during development, our aim was to determine if short periods of maternal separation during breastfeeding induce permanent changes in a number of astrocytes labeled with the glial fibrillary acidic protein in different brain areas. Wistar rats were housed under standard laboratory conditions with reversed light/dark cycle; food and water ad libitum. Pups were separated from their mothers for 6 h daily during breastfeeding period. On day 22, pups were separately housed according to gender and treatment. At day 60, subjects were evaluated in the elevated plus maze and, after processing for immunohistochemistry, 20-μm sections were made. Prefrontal cortex, paraventricular nucleus, preoptic area, hippocampus and amygdala were localized. Labeled cells were quantified using Image-J program. Results showed that separated females had more entries into open arms and spend more time as compared with the control groups. In the prefrontal cortex we identified a decrease in staining cells in separated females, whereas there was an increase in staining cells in separated males. In the hippocampus and preoptic area, we observed a decrease only in separated males. We did not find any differences in the paraventricular nucleus or amygdala. Our results indicate that maternal separation during breastfeeding induces permanent changes in the number of astrocytes in different brain areas of both males and females.

Highlights

Stressful or traumatic experiences that occur in the first years of life affect brain development and behavior of individuals (Neigh, Gillespie, & Nemeroff, 2009)
In previous studies we found that short periods of maternal separation during breastfeeding (MSDB) induced a decrease in anxious behavior as evaluated by the elevated-plus maze (EPM) in adult females but not in males, and those results were associated with a decrease in the immunoreactivity in alpha subunits of GABA-A receptors in the HP, paraventricular nucleus (PVN) and preoptic area (POA) (Moreno, Lamprea, & Dueñas, 2009; León, Riveros-Barrera, & Dueñas, 2012)
Taking into account the existing literature and our previous results, in addition to the known importance of astrocytes in different processes including stress response, learning and memory, the purpose of this work was to assess whether subjects undergoing MSDB presented differences during adulthood in the number of astrocytes immunostained with glial fibrillary acidic protein (GFAP) in the PFC, PVN, POA, AM and HP compared to the same areas in a nonseparated control group

Summary

Introduction

Stressful or traumatic experiences that occur in the first years of life affect brain development and behavior of individuals (Neigh, Gillespie, & Nemeroff, 2009). To study how negative early experiences affect the development of the individual, various animal model studies have been implemented including those investigating alterations in mother– pup interactions (Moriceau, Roth, & Sullivan, 2010; Lesch, 2011; Schmidt, Wang, & Meijer, 2011) One of these models is early maternal separation, which has been widely used as a model of the anxiety, depression and stress caused by neglect (Duque et al, 2011). As maternal separation is considered a stress model (Litvin et al, 2010), it is possible to inquire about the neurobiological mechanisms involved in individual responses because of the activation of the hypothalamus– pituitary–adrenal axis (HPA) (Lajud, Roque, Cajero, Gutiérrez-Ospina, & Torner, 2011), which shows the physiological mechanisms that enable an organism to respond adaptively to threatening stimuli This response occurs, for example, by increasing glucocorticoids and adrenalin from the adrenal glands (Wilber & Wellman, 2009). It has been shown that chronic stress affects the electrophysiological properties of glutamate ionotropic receptors in the HP and prefrontal cortex

Objectives

Methods

Results

Conclusion