The Role of Circadian Signaling in Astronaut Tendon Strength

While many studies focus on how reduced gravity impacts the musculoskeletal system, no work has investigated how circadian rhythm disruption during long-term spaceflight contributes to musculoskeletal tissue abnormalities. My hypothesis is that circadian rhythm disruption compounds the effects of microgravity in disrupting normal tendon maintenance and healing centered around the BMAL1-CLOCK dimer. To test this hypothesis I will simulate the disrupted circadian rhythm with melatonin and oxidative stressors in simulated microgravity, using a normal gravity control. Cells will be monitored for specific epigenetic changes in the BMAL1-CLOCK dimer to discern how the treatment affects the cell environment and to further analyze the degree of circadian disruption present in the cells. Treated cells will be grown into 3D silk constructs and tensile tested to compare the tensile and yield strength of the two groups. Overall, this research aims to evaluate if and how the strength of astronaut’s tendons are affected by alterations of the circadian rhythm in space flight.