Effects of adolescent social isolation on the expression of brain-derived neurotrophic factors in the forebrain

Abstract

Adolescence is a critical period for the development of neural plasticity. Social isolation is an important animal model for various neurodevelopmental disorders. Brain derived neurotrophic factor (BDNF) mediates many important brain functions such as neural plasticity, and aberrations in its expression have been implicated in many brain disorders. However, to date there have been few reports of effects of adolescent social isolation on BDNF expression in adult animals. In the present study, we subjected weaning Sprague Dawley rats to a four-week early adolescence social isolation procedure followed by four-week standard housing until adulthood for molecular assays. BDNF protein levels in several key forebrain regions relevant to brain development were investigated using immunohistochemistry, including frontal and cingulate cortex as well as hippocampus. Our results show that adolescent social isolation significantly increased BDNF protein expression in the medial prefrontal cortex and all three sub-fields of the hippocampus, including CA1, CA2/3 and dentate gyrus. This study advances the use of adolescent social isolation as an animal model for studying neurobiological underpinnings of various neurodevelopmental disorders.