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The Effect of Spaceflight on the Murine Basilar Artery
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Spaceflight poses a serious risk to human cardiovascular health in the form of microgravity-induced fluid shifts, exposure to ionizing space radiation, and unique environmental factors. The combinatorial effects of increased intracranial pressure and high pCOv2 levels on the International Space Station have led to particular concern about cerebral arteries. Two prior studies aimed at examining specific spaceflight-induced changes in murine basilar artery function yielded very different results. Therefore, the goal of this study, part of the NASA Rodent Research 9 mission, was to investigate mechanisms underlying pathophysiological changes in the murine basilar artery and to clarify conflicting results from previous studies. To achieve this goal, we used the technique of wire myography to examine the structural, mechanical, and pharmacological properties of basilar arteries from mice that had experienced 33 days of spaceflight on the International Space Station. Spaceflown mice were compared to a habitat control group, which was exposed to matched environmental conditions but not microgravity and radiation, and a vivarium control group, which was exposed to none of the aforementioned stimuli. Although body weight, basilar artery diameter, and passive pressure-diameter relationship were not different between habitat control, vivarium control, and spaceflight groups, we found that spaceflight induced significant changes in the response of the murine basilar artery to pharmacological agents. Vasoconstriction to U46619 and KCl was diminished to varying degrees in the spaceflight group, as was endothelial-independent vasodilation to DEA-NONOate. Endothelial-dependent nitric oxide-mediated vasodilation in response to acetylcholine, but not ADPβS, was shown to be reduced in the spaceflight group compared to the vivarium control group. Unaltered structural and mechanical properties and decreased U46619- and KCl-mediated vasoconstriction supplement results from a prior study of murine basilar arteries following spaceflight. Preserved vasodilation to ADPβS but not acetylcholine after KCl preconstriction may suggest that spaceflight differentially affects endothelial dilatory pathways. The decrement in endothelial-independent vasodilation, a feature never previously observed in spaceflown mice, presents a new dimension of spaceflight-induced vascular dysfunction.
Frederick Jr., Norman E (2018). The Effect of Spaceflight on the Murine Basilar Artery. Master's thesis, Texas A & M University. Available electronically from