HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dvorscak, L. Articles by Marfurt, C. F. Search for Related Content PubMed PubMed Citation Articles by Dvorscak, L. Articles by Marfurt, C. F.

Age-Related Changes in Rat Corneal Epithelial Nerve Density

From the Department of Anatomy and Cell Biology, Indiana University School of Medicine-Northwest, Gary, Indiana.

PURPOSE. To determine the effect of aging on corneal epithelial nerve density in an animal model.

METHODS. Corneal whole mounts from rats aged 6, 12, 18, and 24 months were stained immunohistochemically with antisera against the pan-neuronal marker neurotubulin. Epithelial nerve terminals and subbasal nerves in standardized 1-mm² central and peripheral zones from each cornea were drawn using a drawing tube attached to a light microscope. Images were scanned, and nerve densities were calculated as the percentage of each 1-mm² area occupied by nerves. The diameters of subbasal nerves in 6- and 24-month old animals were measured. Subbasal nerve vortices were analyzed qualitatively with reference to location, morphologic appearance, and directionality.

RESULTS. Epithelial nerve terminal density decreased by approximately 50% between 6 and 24 months. The rate of decline was roughly linear and similar in both central and peripheral cornea. In contrast, subbasal nerve density increased by more than 50% between 6 and 24 months in both central and peripheral cornea. The mean diameter of corneal subbasal nerves decreased approximately 30% (0.384 µm vs. 0.271 µm) between 6 and 24 months. The morphologic appearance and directionality of the subbasal nerve vortex demonstrated considerable interanimal variability and did not correlate with age.

CONCLUSIONS. Rat corneal nerve terminal density decreases, but corneal subbasal nerve density increases, as a function of age. The age-related loss of nerve terminal density seen in the rat cornea is in keeping with the decreased corneal sensitivity reported in elderly humans and may contribute to the pathogenesis of dry eye disease in aged persons.

This article has been cited by other articles:

				C. Q. Yu, M. Zhang, K. I. Matis, C. Kim, and M. I. Rosenblatt Vascular Endothelial Growth Factor Mediates Corneal Nerve Repair Invest. Ophthalmol. Vis. Sci., September 1, 2008; 49(9): 3870 - 3878. [Abstract] [Full Text] [PDF]