Alexander M Schreiber
The experimental goal is to study the roles of two hormones in frog immune system development. Frogs are unique among vertebrates since during metamorphosis the tadpole immune system is destroyed and replaced by a new adult immune system. This experiment had four groups of pre-metamorphic tadpoles. The first was an untreated/control group. The second was exposed to dexamethasone (Dex), a pharmacological glucocorticoid analog. The third was treated with thyroid hormone, T3. The fourth was exposed simultaneously to both hormones, which happens during natural metamorphosis. This experiment was performed in both short term (2 days) and long term (5 days) to see the effects of these hormones over different time periods. The animals were euthanized and dissected to measure the size of the thymus gland, a key component of the immune system. After measuring thymus size, the glands were embedded, sectioned onto slides and prepared to be stained with fluorescently labelled antibodies against active caspase-3 and phospho-histone H3 to measure cell apoptosis and proliferation, respectively. The data was analyzed using “Image-J”, 1-Factor analysis of variance (ANOVA) test, and Tukey’s pair wise comparison test to quantify changes in size.