Increase in blood-brain barrier permeability by altitude decompression

Area of Science:

• Neuroscience
• Physiology
• Aerospace Medicine

Background:

• Previous research suggests compression-decompression affects blood-brain barrier (BBB) permeability.
• Understanding BBB changes during altitude decompression is crucial for safety in aviation and space exploration.

Purpose of the Study:

• To investigate functional and ultrastructural changes in the blood-brain barrier (BBB) induced by simulated altitude decompression.
• To assess the impact of altitude decompression on BBB permeability to tracers.

Main Methods:

• Rabbits were subjected to simulated altitude decompression (30,000 ft for 45 min).
• Intravenous injection of trypan blue and horseradish peroxidase was used to assess BBB permeability.
• Brains were examined macroscopically, microscopically, and via spectrophotometric dye determination.

Main Results:

• Experimental animals exposed to altitude decompression showed significantly higher tracer penetration in their brains compared to controls.
• Mean dye concentration was substantially elevated in the brains of rabbits exposed to decompression.
• Electron microscopy indicated increased permeability was mediated by transendothelial vesicular transport and junctional penetration.

Conclusions:

• Altitude decompression causes significant functional and ultrastructural alterations to the blood-brain barrier.
• These BBB changes may have implications for drug delivery and understanding the mechanisms of altitude decompression sickness.
• Findings are relevant to pharmacotherapy considerations for individuals in high-altitude or space environments.