Date of Award
Master of Science (MS)
Prolonged consumption of carbohydrate-rich diets and immobile lifestyles frequently cause metabolic disorders and obesity and, as a result, may lead to progressive heart dysfunction among broad social groups of the population. Drosophila melanogaster serves as an essential model organism in cardiovascular disease research due to conserved physiological and genomic traits shared with humans, its genetic and molecular toolbox versatility, and cost-effective maintenance. Here, we combine optogenetics and optical coherence tomography to study cardiovascular function in D. melanogaster. A new optogenetic pacing system has been developed, employing a transgenic line carrying two opsins: ChR2 and NpHR2.0. A custom-built hardware setup including optical coherence microscopy (OCM) and a dual-color LED light pulse generation module was used to perform the heart imaging and pacing experiments non-invasively, through activation (ChR2) and inhibition (NpHR2.0) of cardiac tissue by exposure to blue (~480 nm) and orange/red (~590 nm) light, respectively. We have characterized the double transgenic line expression and optimized the light stimulation parameters. Next, we applied well established high-sugar dietary model in Drosophila and studied the physiological response during the cardiac optogenetic stimulation experiments in larvae and pupae. We focused on the optimal irradiance level required, paceable heart rate range, contract time, and so on. These parameters were compared with larvae and pupae reared on a normal (low sugar) diet. The obtained results provide information on the disease progression at early developmental stages. The preliminary data suggests that high-sugar diet feeding affects the heart dynamics in young animals. It needs more experiments to determine the mechanism and brings future research to look into the late developmental stages such as the adult fly.
Chao Zhou Biomedical Engineering
Song Hu,Jianmin Cui