The detrimental effects of spaceflight on the cardiovascular system are well known. It is believed that these effects may lead to clinically significant risks to astronauts on long duration space missions as well as to the success of these missions themselves. Current studies are limited primarily to human studies and rodent experiments. However, these model systems have significant limitations that may be addressed by using the well-established Drosophila model. Drosophila have previously been successfully launched into space and a ground-based Drosophila model for cardiac disease and function has been developed. However, the genetically versatile Drosophila model has yet to be used for studying the effects of spaceflight on the cardiovascular system.
In this proposal we propose to fly groups of Drosophila aboard the International Space Station for approximately 30 days, along with identical on-board 1-g controls as well as ground controls. The Drosophila will require minimal astronaut intervention involving changing feeding trays on 1 or 2 occasions. The samples will be retrieved post-flight and analyzed using established methods. Heart function, including measurements of diastolic and systolic intervals, heart rate, heart diameters, contractility, and arrhythmias will be recorded. Microscopic and immunohistochemical evaluations of heart morphology will also be carried out. We will also conduct intracellular membrane potential recordings of the heart. Finally, we will analyze mRNA expression with a microarray.
The ultimate goal of this research is to obtain data while validating the Drosophila model for studying the effects of spaceflight on cardiac disease and function. The development of such a model would be a potentially significant advancement in the study and understanding of how spaceflight affects the cardiovascular system, and may ultimately lead to countermeasures to prevent them.
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We will use our well established procedure to evaluate heart function in flies. Heart function in ground controls and space flown flies will be analyzed (Fink, 2009). We will also analyze muscle structure using immunohistochemical and electron microscopy techniques (Alayari, 2011).
Analysis and results are available in the NASA GeneLab repository, https://genelab.nasa.gov/data/.
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