Age-related changes in rat corneal epithelial nerve density

Area of Science:

• Ophthalmology
• Neuroscience
• Gerontology

Background:

• Corneal nerve structure and function are crucial for maintaining ocular surface health.
• Age-related changes in the nervous system can impact sensory perception and tissue homeostasis.
• Understanding age-related alterations in corneal innervation is vital for addressing ocular surface diseases in aging populations.

Purpose of the Study:

• To investigate the impact of aging on corneal epithelial nerve density in a rat model.
• To quantify age-related changes in both epithelial nerve terminals and subbasal nerves.

Main Methods:

• Corneal whole mounts from rats of different ages (6, 12, 18, 24 months) were analyzed.
• Immunohistochemistry using a pan-neuronal marker (neurotubulin) identified nerve structures.
• Nerve densities were calculated using image analysis, and subbasal nerve diameters were measured.

Main Results:

• Corneal epithelial nerve terminal density decreased by approximately 50% with age.
• Subbasal nerve density increased by over 50% in aging rats.
• Mean subbasal nerve diameter decreased by about 30% in older rats.

Conclusions:

• Aging leads to a significant decrease in corneal epithelial nerve density and an increase in subbasal nerve density in rats.
• These findings correlate with reduced corneal sensitivity in elderly humans and may contribute to the pathogenesis of age-related dry eye disease.