A simple method for morphological assessment of astrocytes: sexual dimorphism in the maturation dynamics of astrocytes in the rat amygdala

Simple, affordable and reliable methods for assessing the status of brain structures maturation are vital for preclinical studies related to the effects of early-life stress. These methods make it possible to evaluate the effectiveness of specific therapies or the prevention of stress-related pathological changes. The morphology of astrocytes is one of the markers representing functional state of synapses and thus it is indicative of maturation state of neuronal networks. We performed the method for evaluating the morphological characteristics of astrocytes using epifluorescence microscopy and the ImageJ program. Application of the method to brain sections of rats on postnatal days 18 and 30 revealed the dynamics of morphological changes in the astrocytes of the basolateral nucleus of the amygdala during normal ontogenesis. The proposed method makes it possible to evaluate not only the density of the cell population, but also their morphological parameters associated with the degree of branching and the length of the astrocyte processes. The approach used revealed sexual dimorphism in the ontogenesis: the length of the astrocytic processes increased during maturation from juvenile to pubertal period in the basolateral nucleus of the amygdala only in female rats, but not in males.