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EXPERIMENT INFORMATION

Temporal Impact of Simulated Microgravity on Ocular Vascular Hydrodynamics (80NSSC19K1025)
Principal Investigator
Research Area:
Cell and molecular biology
Species Studied
Scientific Name: Mus musculus Species: Mouse Strain: C57BL/6

Description
OBJECTIVES:
Spaceflight associated neuro-ocular syndrome (SANS) is reported to affect about 40% of astronauts completing long-duration spaceflights and is characterized as the development of one or more findings: optic disc edema, hyperopic shifts, globe flattening, cotton-wool spots, retinal nerve fiber layer thickening, or choroidal folds. Although prolonged exposure to the headward fluid shift occurring in microgravity is regarded as the primary instigating factor, the pathophysiology of SANS remains unclear. An additional gap in our knowledge is whether ground-based models of microgravity can simulate SANS. Thus, ground-based studies of ocular vascular hydrodynamics are required to clarify if chronic mild elevations of ocular pressure variables compromise ocular structure and function.

Since all blood and lymph vessels are compliant, fluid-filled structures whose pressures are strongly influenced by gravity, we will focus on potential changes directly to the ocular vasculature caused by simulated microgravity. Therefore, the objective of this study is to determine whether the hindlimb unloading (HU) model of simulated microgravity causes a time-dependent change in structure and function of the ocular vasculature at the level of feed arteries, venous exchange vessels and lymph vessels, and whether sex differences influence these responses. The central hypothesis is that simulated microgravity causes temporal changes in structure/function of the ocular vasculature and subsequent alterations in ocular hydrodynamics leading to SANS.

These studies will provide a novel comprehensive evaluation of the temporal impact of simulated microgravity on ocular hydrodynamics in all the main microvascular compartments (feed arteries, veins and lymphatic vessels), and correlation of these findings with SANS. Outcomes will help identify the strengths and limitations of a murine HU model for SANS.


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Parameters
Central retinal artery flow
Cytokine levels
Electroretinogram waves
Intraocular pressure
Protein expression
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Ground 05/01/2009 In Progress

Additional Information
Managing NASA Center
Ames Research Center (ARC)
Responsible NASA Representative
Ames Research Center LSDA Level 3
Project Manager: Helen Stewart
Institutional Support
National Aeronautics and Space Administration (NASA)
Proposal Date
07/01/2019
Proposal Source
2016-17 Space Biology (ROSBio) NNH16ZTT001N-FG. App G: Flight and Ground Space Biology Research