Experimental and numerical quantification of influences of drugs on zebrafish larvae swimming kinematics and energetics

Student thesis: Doctoral Thesis

Abstract

The use of zebrafish larvae has aroused wide-interest in the medical field for its potential role in the development of new therapies. Compared to other species, the zebrafish larvae grow extremely quickly, and the embryos are nearly transparent, which allows easy examination of its internal structures using fluorescent imaging techniques. Its complete genome sequence has already been published and is quite similar to that of human beings. Together with other advantages such as 2-6mm tiny body size for large scale screening, zebrafish has been grown to be a valuable model to test drugs and human diseases. Different types of drugs might have different influences on zebrafish behaviors, these behavior changes are related to functional changes of motoneurons in the spinal cord in the central nervous system (CNS) and transformations of the zebrafish body such as muscle mechanical power and force variation, which cannot be measured directly by pure experimental observation.Therefore, a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. In this study, a novel methodology has been developed to investigate the influences of drugs on zebrafish larvae kinematics and energetics including the internal muscle mechanics, which can supply additional information on zebrafish swimming behavior changes induced by drug applications.The method includes both experimental measurement and numerical simulation. The experimental study is carried out with high-speed camera recordings on real zebrafish larvae swimming behaviors and post-processing with multi-function in-house MATLAB code to capture and extract the body motion data. The numerical simulation is based on coupling between open-source CFD toolbox OpenFOAM, and an open-source multibody dynamics software MBDyn to accurately quantify influences of drug applications on zebrafish larvae kinematic and energetic performances, and especially internal muscle mechanics. For the interactions between zebrafish larvae and surrounding fluid, OpenFOAM is used to solve fluid dynamics and deal with dynamic internal mesh motion; MBDyn is used for solid body analysis and provide kinematic data for OpenFOAM. The coupling of these two solvers is achieved by establishing an interface library to exchange data with the help of the TCP/IP protocol.Test cases are studied to validate the feasibility and accuracy of the numerical methodology. The first step validation includes comparisons with past research of a 2-D jellyfish-like multi-body structure to prove that numerical coupling between OpenFOAM and MBDyn is feasible in simulating multi-body structure. The second step validation includes comparisons between 3-D zebrafish model and experimentally observed results with high-speed camera. To be specific, tail-beat angles and averaged forward velocity of zebrafish larvae are compared, and all the quantitative comparisons show acceptable similarities. Also, zebrafish body curvatures are compared between experiment and CFD during one period of time to supplement the validation for accuracy of numerical simulation.Applications of our methodology include nociceptive and neuroactive drug influenceson zebrafish locomotion and additional information from our results such as internal muscle mechanisms, to assist the evaluation of Gypenosides protection from high concentration acetic acid. We firstly provide comparisons of zebrafish locomotion before and after treatments with 0.01% acetic acid, 500 uM diphenylhydantoin (DPH),and 100mg/ml yohimbine to test whether our novel zebrafish model can simulate different types of drug effects (positive, negative and no effect) on zebrafish larvae ornot. The reason of choosing the three drugs is based on previous studies showing apparent physiology and behavioural changes under biological experiments. Based on our results, the
Date of Award9 Oct 2020
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorQing Xiao (Supervisor) & Hui-Rong Jiang (Supervisor)

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