(625u) Central Nervous System Development In Planaria As a Model for Studying the Dynamics of Fetal Alcohol Syndrome

Fetal Alcohol Syndrome (FAS) affects approximately 3-5 children of every 1,000 live births in the United States.  It manifests as an underdeveloped central nervous system with symptoms such as cognitive deficiencies, learning disabilities, and craniofacial abnormalities.  FAS is thought to be caused by an alcohol-induced disturbance to the dynamic process of central nervous system (CNS) development.  However, the molecular mechanisms underlying this disturbance have been challenging to study using traditional animal models, and therefore relatively little is known about the dynamic molecular etiology of FAS.  We present a preliminary study on the effects of alcohol exposure on CNS development in a new animal model, Schmidtea mediterranea planaria.  Planaria are small freshwater flatworms considered to be the simplest organism with a CNS.  They have the remarkable ability to regenerate complete, fully-functional planaria from any fragment within approximately 7 days.  

To assess CNS developmental dynamics during alcohol exposure, we conducted behavioral and functional assays throughout development in head-regenerating planaria.  Worms were transferred to alcohol-containing solutions (1-4% v/v) following head removal.  On each of the subsequent 9 days, the planarian movement and light avoidance tendencies were quantified.  While these functions were not different in intact worms exposed to low levels of alcohol and alcohol-naïve intact worms, alcohol exposure during head regeneration induced a delay and retardation of CNS development.  The severity of these effects increased in a statistically significant dose-dependent manner, indicating that there is a dynamic response to alcohol exposure during CNS development in head-regenerating planaria.  Our results suggest that head-regenerating planarian fragments exposed to low levels of alcohol can be used as a model system for studying the alcohol-induced disturbance of fetal CNS development.