Nucleus reuniens of the midline thalamus of a rat is specifically damaged after early postnatal alcohol exposure

This study is the first to report the long-term neuroanatomical alterations to the ventral midline thalamus after alcohol exposure on postnatal days 4–9 (a rodent model of binge drinking during the third-trimester of human pregnancy). Alcohol added to a milk formula was administered to female Long–Evans rat pups on postnatal days 4–9 (5.25 g/kg/day of ethanol, intragastric intubation). Control animals were intubated without the administration of liquid. In adulthood, brains were immunohistochemically labeled for a neuronal marker (NeuN) conjugated with Cy3 fluorophore and stained with Hoechst33342 to visualize nuclei. Total non-neuronal cell number (NeuN−/Hoechst+) and neuron number (NeuN+/Hoechst+), and total volume were estimated using unbiased stereology in two neighboring midline thalamic nuclei: reuniens and rhomboid. Estimates were analyzed using linear mixed modeling to account for animal and litter as clustering variables. A 21% reduction in the total neuron number (resulting in altered neuron-to-non-neuron ratio) and an 18% reduction in total volume were found exclusively in thalamic nucleus reuniens in rats exposed to ethanol. Non-neuronal cell number was not changed in reuniens. No ethanol-induced changes on any measures were observed in rhomboid nucleus. These specific neuroanatomical alterations provide a necessary foundation for further examination of circuit-level alterations that occur in fetal alcohol spectrum disorder.
Source: NeuroReport - Category: Neurology Tags: DEGENERATION AND REPAIR Source Type: research