In Vitro and In Vitro Models for Alcohol Toxicity to the Extracellular Matrix of Astrocytes

Ethanol exposure exerts profound effects on the developing brain, which lead to cognitive impairment and behavioral functional disorders as seen in fetal alcohol spectrum disorders (FASD). Astrocytes play a major role in neuritogenesis and neurite outgrowth by modulating neuronal plasticity through the regulation of the composition of the extracellular matrix (ECM), which is involved in the extension of neurites and the formation and remodeling of synaptic connections. Ethanol affects the levels of neuritogenic ECM proteins release by astrocytes and inhibits neuronal plasticity. In this unit, we describe in vitro and in vivo models of developmental ethanol exposure in which to investigate mechanisms of ethanol-induced alterations in the astrocyte ECM leading to abnormal neuronal development. The described in vitro model consists of primary astrocyte cultures exposed to ethanol in sealed chambers and of astrocyte/neuron co-cultures in which neurons are in contact with astrocytes previously exposed to ethanol. The in vivo model consists of neonatal rat pups exposed to ethanol via intragastric intubation. The developmental stage of the brain of neonatal rats in this model is comparable to the developmental stage of the human brain during the third trimester of gestation. This in vivo FASD model recapitulates some of the behavioral effects of developmental ethanol exposure in humans. A description of how to determine changes in ECM proteins after in vitro and in vivo ethanol exposure will also be provided, as well as procedures for assessing neurite outgrowth in the in vitro model and dendrite arborization in the in vivo model. These two models are instrumental to the investigation of how ethanol, during brain development, alters the composition of astrocyte-secreted ECM leading to altered brain development.