Press Release: Frogs and Alcohol- Unlikely Pair Give Insights for Neurological Disorder

Marisa Bennett

Can a warning label on a bottle of alcohol perpetuate stigma? Indeed, Emily Bell, a researcher at Neuroethics Research Unit in Montreal Canada, and her colleagues believe that the well intentioned labels have been responsible for specific negative effects. Women and children experience this stigma because of the societal perceptions around Fetal Alcohol Spectrum Disorder (FASD). Fetal Alcohol Spectrum Disorder is a neurological disorder caused by early exposure to alcohol while in the womb. Over the years, there has been a rising awareness of Fetal Alcohol Spectrum Disorder’s prominence in the United States. 

Based on the National Institute of Health’s (NIH) studies, the CDC estimates that approximately 1 percent of the United State’s population is affected by this disorder. Evidence also suggests that as many as 1 in 26 women report drinking more than four drinks at a time, according to the CDC. Despite the prevalence of Fetal Alcohol Spectrum Disorder and the known ramifications, there is no consensus on acceptable alcohol limits and even controversy as to how much alcohol is acceptable. Madison Durbin, an undergraduate at Duquesne University, sought to address this social issue and explore whether minute quantities of alcohol could have measurable effects on development. Using baths with small doses of ethanol, an alcohol, and tadpoles, Madison found some intriguing results. 

At first one may ask, why frogs? Madison hoped to translate the findings in the experiment to human development. This is possible because frogs share several common characteristics in development that can allow inferences to human development. These include several genes, morphology, and the endocrine system. In addition to these similarities, Madison chose to experiment with frogs because of the ease of controlling the exposure to alcohol and their development externally from the mother. 

Having determined an ideal model organism, Madison and her colleagues, decided to expose tadpoles ten days after hatching to different concentrations of ethanol, an alcohol. The concentrations included 0.4 percent ethanol and 0.009 percent ethanol, alongside a control of filtered water. This first concentration was chosen because previous literature had noted that 1 percent was where observable malformations were no longer detectable. The 0.009 percent concentration was chosen to test if extremely low concentrations did alter development. Each of these concentrations explore whether small levels of alcohol could impact development, which would later be compared to the control with normally developed tadpoles.

After several weeks of exposure, experiments were done to test behavior, mass/morphology, and the corticosterone hormone. Corticosterone is a stress hormone and plays a vital role in the development from tadpole to frog, as found in a study by Dr. Leena Shewade, Dr. Daniel Buchholz and other collaborators from the University of Cincinnati. After completion of the treatments, the tadpoles were physically examined. Observations showed three significant differences between the tadpoles in the control group and in the group with low doses of ethanol.

First, in the 0.04 percent group, there was a significant increase in body mass and the mouth width, suggesting that alcohol exposure impacted physical development of tadpoles. Secondly, their findings indicated increased stress levels associated with the hormone corticosterone. High corticosterone levels have been linked to compromised immune systems as shown in a study, conducted at the University of California Riverside. This study found elevated levels of immune cells in frogs making them susceptible to pathogens and diseases. Lastly, while there were observed mass and corticosterone differences, there were no observed behavioral differences. With significant differences in body mass, morphology, and increased hormone levels, Madison’s findings suggest that there are measurable effects of early alcohol exposure. 

The results indicated significant differences between the normally developed tadpoles and the tadpoles in 0.4 percent ethanol exposure. This suggests that there are altered outcomes due to alcohol exposure. The 0.4 percent concentration was lower than the previously expected safe level of alcohol on frog development. Low doses, although seemingly benign, can negatively impact development. While still preliminary, Madison’s results promote findings to encourage further exploration on low dose alcoholism on fetal development. Small amounts of drinks over the course of development may have consequences. To address the limitations of the frog model, further studies should be conducted to explore the potential impacts of low level alcohol consumption during pregnancy. With greater clarity, controversy and unknowns can be remedied with both informed mothers and public health policy.

SOURCES

  1. Data & Statistics. (n.d.). Retrieved March 31, 2021, from https://www.cdc.gov/ncbddd/fasd/data.html#ref

  2. FASDs: Information for Women. (n.d.). Retrieved March 31, 2021, from https://www.cdc.gov/ncbddd/fasd/women.html

  3. Bell, E., Andrew, G., Di Pietro, N., Chudley, A. E., N. Reynolds, J., & Racine, E. (2016). It’s a Shame! Stigma Against Fetal Alcohol Spectrum Disorder: Examining the Ethical Implications for Public Health Practices and Policies. Public Health Ethics9(1), 65–77. https://doi.org/10.1093/phe/phv012