Effects of Essential Oil from Thymus vulgaris on Viability and Inflammation in Zebrafish Embryos.

Innate immunity provides the initial response against pathogens and includes the inflammatory response. Regulation of the initiation and duration of neutrophil and mononuclear cell influx during inflammation determines both the successfulness of pathogen elimination and the level of resulting tissue damage. Zebrafish embryos provide excellent opportunities to visualize the inflammatory response. Neutrophil granules may be stained with Sudan black, and variation in neutrophil counts may be used to monitor the level of the response. Inflammation may be triggered by injuring the caudal fin, providing an opportunity for testing possible anti-inflammatory compounds in a whole-animal system. The use of homeopathic compounds as anti-inflammatory treatments is common in alternative medicine. Effects of unfractionated essential oil from Thymus vulgaris and its specific component, carvacrol, have been examined in cells in culture and in rodents. Our work extends this research to zebrafish, and includes toxicity and morphological studies as well as examination of anti-inflammatory effects following tail fin injury. Our results show that zebrafish are more sensitive to thyme oil compared to cells in culture, that cardiac defects arise due to thyme oil treatment, and that thyme oil reduces neutrophil infiltration during an inflammatory response.

Integration of a zebrafish research project into a molecular biology course to support critical thinking and course content goals.

Engaging undergraduates in research is essential for teaching them to think like scientists, and it has become a desired component of classroom and laboratory instruction. Research projects that span an entire semester expose students to a variety of concepts and techniques and allow students to use experiments to learn scientific principles, understand why specific techniques are applicable, critically analyze varied data, and examine how experimentation leads to acquiring knowledge. To provide an experience with these features, a semester long research project was integrated into a combined lecture and laboratory course, Molecular Biology. The project utilized the zebrafish model to examine gene expression during embryonic development and required students to develop and test hypotheses about the timing of expression of previously uncharacterized genes. The main goals for the project were to provide opportunities for students to develop critical thinking skills required for conducting research and to support the content goals of the course. To determine whether these goals were met, student performance on the steps of the project and related pre-test and post-test questions was examined. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(6):565-573, 2016.