Protein in rabbit lacrimal gland fluid

Area of Science:

• Ophthalmology
• Tear Film Research
• Biochemistry

Background:

• Tears contain various proteins, with the lacrimal gland presumed to be the primary source.
• Previous studies suggested lacrimal gland protein secretion in response to cholinergic stimulation.
• The exact contribution of the lacrimal gland to tear protein concentration remained unclear.

Purpose of the Study:

• To quantify protein concentration directly from lacrimal gland fluid.
• To investigate the relationship between lacrimal gland fluid flow rate and protein concentration.
• To differentiate lacrimal gland secretions from other orbital gland contributions.

Main Methods:

• Collection of fluid directly from the main excretory duct of the lacrimal gland.
• Measurement of protein concentration in the collected lacrimal gland fluid.
• Analysis of protein concentration relative to varying lacrimal gland fluid flow rates.

Main Results:

• Lacrimal gland fluid protein concentration was higher than plasma at flow rates of 2-10 microliter/min.
• Protein concentration in lacrimal gland fluid matched plasma levels at flow rates below 2 microliter/min and above 10 microliter/min.
• This indicates a flow-rate-dependent protein concentration in lacrimal secretions.

Conclusions:

• The lacrimal gland actively secretes proteins, with concentration varying by flow rate.
• Lacrimal gland fluid is a significant contributor to tear protein content, particularly at moderate secretion rates.
• Findings provide direct evidence for the lacrimal gland's role in tear protein homeostasis.