Macromolecular transport in the spiral prominence

Area of Science:

• Ototopical research
• Cellular biology
• Macromolecule transport

Background:

• The spiral prominence is a key structure in the inner ear responsible for endolymph production.
• Understanding macromolecule transport mechanisms within the spiral prominence is crucial for auditory health.

Purpose of the Study:

• To investigate the transport of macromolecules into and out of the spiral prominence in guinea pigs.
• To elucidate the cellular mechanisms involved in horseradish peroxidase (HRP) uptake and transport.

Main Methods:

• Intraperilymphatic and intravenous injection of horseradish peroxidase (HRP) in guinea pigs.
• Morphological analysis using electron microscopy to observe HRP localization and cellular uptake.
• Evaluation of endocytic and vesicular transport pathways.

Main Results:

• HRP was significantly taken up by spiral prominence epithelium from both perilymphatic and endolymphatic spaces, with higher uptake from endolymph.
• Stroma cells surrounding the spiral prominence vessel exhibited high endocytic activity, storing HRP within cytoplasmic vesicles.
• Morphological evidence suggested lysosomal digestion of HRP within epithelial and stroma cells.
• Vesicular transport across the vessel wall facilitated HRP movement from the perilymphatic space into the spiral prominence vessel lumen.

Conclusions:

• The spiral prominence epithelium actively transports macromolecules via endocytosis and vesicular transport.
• Lysosomal pathways are involved in processing transported macromolecules.
• There is a unidirectional transport of HRP from the perilymphatic space into the vessel lumen, with no observed transport in the reverse direction.