The Use of Drosophila melanogaster as a Model to Investigate the Underlying Cellular and Molecular Basis of TBI

Event Center BC

Each year in the United States, 1.7 million people experience a traumatic brain injury (TBI). A TBI is characterized by the severe impact to the cranial region in which the brain consequently slams against the inside of the skull. This can result in swelling and bruising of the brain, which can lead to decreased brain function. TBI is a substantial health issue worldwide, yet the mechanism responsible for its complex spectrum of pathologies remains largely unknown. Sustained TBI’s have been shown to increase the likelihood of developing Alzheimer’s and other neurodegenerative diseases. Our research aims to identify some of the possible cellular and molecular mechanisms of TBI by utilizing the model organism Drosophila melanogaster. Two strains of D. melanogaster were used in this study, a transgenic AB 42 strain that expresses a 42 amino acid long peptide that has been reported as a possible cause of Alzheimer’s disease, and a genetically matched 00C strain that serves as the control. The TBI model for D. melanogaster consists of the use of a spring action apparatus that delivers a strong jolt of 0.1 sec. The experimental design included: 00C untreated flies, 00C treated with 5 daily TBI’s, 00C treated with 10 daily TBI’s, AB 42 untreated flies, AB 42 treated with 5 daily TBI’s, and AB 42 treated with 10 daily TBI’s. Lifespan, cognitive ability (negativegeotaxis assay), neuron viability (GFP), and neuron quantity were analyzed to assess the effects of TBI. Although it was found that the AB 42 strain and the 00C strain showed the same inverse relationship between TBI treatments and lifespan, the AB 42 strain experienced a shorter lifespan than the 00C strain. Results from the climbing assay show the same trend for both strains in that increased daily TBI inducing treatments resulted in decreased climbing ability, however, each treatment group in the AB 42 strain showed a greater decreased climbing ability than that of the 00C strain. In terms of cholinergic neuron function, groups treated with ten daily TBI’s experienced the sharpest decline. Neuronal function assessment indicates the AB 42 strain had a lower average and lower deviation in measured intensity of GFP expression, whereas the 00C strain had a higher average and higher deviation in measured intensity of GFP expression. In future studies, behavioral assessments could also be incorporated such as a sugar preference assay or odor avoidance assay as they might give us a better insight on the behavioral pathologies identified in humans.