Our laboratory takes a comparative medicine approach to studying human disorders by using a variety of animal models of disease. The current emphasis in the lab is on the study of polycystic kidney disease, hereditary deafness, and inflammatory bowel disease. Using both rodent and zebrafish models, we are interested in characterizing disease-causing genes and their protein products in order to elucidate the molecular pathways in which these genes/proteins participate. This knowledge will allow a better understanding of both normal and abnormal development and may ultimately lead to targeted therapeutics. Additionally, we are interested in the generation and characterization of new animal models. Our lab has been involved in efforts to characterize rat embryonic stem cells (ESCs), isolate new rat ESC lines, create and validate a novel rat and zebrafish cell ablation model system and use evolving technologies such as CRISPR/Cas9 to create new genetically engineered rat models. We are currently studying the role of microbiome on animal model phenotypes, including zebrafish models of stress and anxiety.
Probiotics Can Reduce Stress Levels and Anxiety
Probiotics, or beneficial live bacteria that are introduced into the body, have become increasingly popular as a way to improve health and well-being. Previous studies have shown a direct correlation between gut microbes and the central nervous system. Using a zebrafish model, our research team determined that a common probiotic can decrease stress-related behavior and anxiety.
In the first study, we added Lactobacillus plantarum, a bacteria found in yogurt and probiotic supplements to certain tanks housing zebrafish while other tanks of zebrafish received no probiotics. Then, using sophisticated computer measuring and imaging tools, we analyzed the behavior of fish when they were placed in a new tank.
Previous studies of fish behavior have found that fish that are anxious tend to spend more time at the bottom of their tanks. In our study, we found that while the untreated fish tended to spend more time in the bottom of the tank, the fish that had been given probiotics tended to spend more time toward the top. This difference in behavior suggested that the probiotic-treated fish were less stressed or anxious.
It is also well known that there is a strong link between the microbes that live in our gut and our overall health and there is communication between gut bacteria and our brains.
To explore this in zebrafish, we performed experiments in which environmental stressors, such as isolation, crowding, or temperature change were introduced to both groups. These stressors are similar to those humans might experience and in the fish, they result in the production of cortisol which is the same stress hormone produced by people.
We found that exposure to stress changed the gut bacteria in the untreated fish but the fish who received the probiotic were protected from dramatic alterations in gut bacteria. This finding underscores the link between gut bacteria and stress and suggests that probiotics may provide protection against the negative impacts of stress on our gut microbes.
Our team plans to continue studying how gut bacteria affect behavior in zebrafish and how that might lead to a better understanding of how probiotics may affect humans.