Characterising epi-perineurial barrier function by microscale techniques including a miniaturised Ussing chamber.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Physiology

Background:

• Peripheral nerve barriers, including the epi-perineurium (EPN), are vital for nerve homeostasis but their role in neuropathy is poorly understood.
• Experimental analysis of these barriers is challenging due to accessibility issues.

Purpose of the Study:

• To develop a novel method for analyzing the electrophysiological properties of the EPN barrier.
• To investigate the EPN's role in maintaining sciatic nerve ion gradients.
• To examine EPN barrier function in a model of bortezomib-induced polyneuropathy.

Main Methods:

• Development of a miniaturized, edge damage-free Ussing chamber for EPN analysis.
• Electrophysiological characterization including transepiperineurial resistance and impedance spectroscopy.
• Determination of ion and flux marker permeability using dilution and bi-ionic potential measurements.

Main Results:

• The EPN functions as a tight and responsive barrier, regulating ion gradients.
• In a rat model of bortezomib-induced polyneuropathy, EPN exhibits increased potassium permeability.
• This increased potassium permeability normalized with animal recovery.

Conclusions:

• A dependable method for analyzing microscale barriers like the EPN was established, applicable to other tissues.
• The EPN is a critical barrier for maintaining sciatic nerve ion homeostasis.
• EPN dysfunction, specifically altered potassium permeability, is implicated in polyneuropathy.