The University of Cincinnati College of Medicine is now home to a state-of-the-art zebrafish research facility — the only one of its kind at UC.
Michelle Kossack, PhD, an assistant professor in the Division of Environmental Genetics and Molecular Toxicology in the Department of Environmental and Public Health Sciences, joined the faculty late last year. Her lab in the Kettering Lab Complex, partially funded through a $250,000 National Institute of Environmental Health Sciences career transition grant, houses about 750 tanks on 10 racks and has the capacity to scale up to as many as 7,000 fish within about 600 square feet.
Kossack studies reproductive toxicology and uses the zebrafish to better understand the molecular mechanisms behind reproductive biology and infertility in humans, as well as how reproductive diseases develop.
“My lab will use zebrafish to model human reproductive development and the impacts of exposure to environmental contaminants and how that affects fertility,” said Kossack.
WHY ZEBRAFISH?
Zebrafish are widely used as a model vertebrate organism. “Zebrafish share 70% of their genes with humans,” said Kossack. “We study them because they provide a simplified model.”
Like humans, zebrafish begin as a single cell and later develop brains and limbs. They can be easier to study than other animal models because they share a similar circadian rhythm with humans, meaning they are generally awake during the day and sleep at night, Kossack explained. Of course, one major difference between zebrafish and humans is how they breathe.
Researchers often prefer zebrafish because of their scalability and high reproduction rates. The zebrafish research community also shares specimens. Through collaboration and spawning within her lab, Kossack will gradually increase the population.
The lab features a recirculating water purification system for the tanks. “It reduces the total amount of water used by removing waste products and recirculating the clean water,” said Kossack.
Although they need less maintenance than many animal models, they still require daily feeding. Kossack will employ a lab assistant and work with students to care for the fish each day, including weekends.
KOSSACK’S RESEARCH
Kossack’s lab studies the effects of dioxin, an industrial byproduct and persistent environmental pollutant produced by burning fuel, incinerating waste and wildfire smoke.
Scientists see dioxins accumulate primarily in animal fat, and about 90% of human exposure occurs through consuming contaminated meat, dairy and fish.
“We take in dioxins mostly through our diet, but they are difficult to avoid because they are so ubiquitous in our environment,” said Kossack. “We are all born with dioxins in our bodies.”
Dioxins are developmentally toxic and are known endocrine disruptors and carcinogens. Kossack is working to better understand the implications of dioxin exposure in human infertility to inform potential future protections and treatments. “We know exposure to certain environmental contaminants affects fertility,” said Kossack. “It’s thought to be a significant factor in the global rise in infertility rates.”
Kossack said although dioxins are known to reduce fertility, the mechanisms are not fully understood. Her research is exploring how dioxins target specific molecular pathways. “First, we will address those questions in zebrafish, then translate that evidence to humans,” said Kossack.