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Abstract #18482 Published in IGR 3-3
A morphometric study of age changes in the rat optic nerve
Cavallotti D; Cavallotti C; Pescosolido N; Iannetti GD; Pacella EOphthalmologica 2001; 215: 366-371
Age-related changes of the optic nerve fibers were studied in three-month-old (young), 12-month-old (adult), and 24-month-old (aged) male Sprague-Dawley rats. The optic nerve was harvested with particular care from the intracranial portion. Cross-sections from the optic nerve of animals from different age groups were stained with toluidine blue and examined under a light microscope at low and high magnifications. Other sections were stained for the demonstration of glial cells, using the method described by Holzer. A third group of sections was stained by the immunohistochemical method to detect glial fibrillar acidic protein, which is a marker for localizing and characterizing astrocytes. All these morphological results were subjected to the quantitative analysis of images and to the statistical analysis of the values to identify significant morphometric data. Biochemical doses of proteins were also performed on homogenized fragments of the optic nerve. The results demonstrate that the following age-related changes can be observed: (1) an increase in meningeal membranes; (2) an increased number of astrocytes; (3) an increase in areal density of glial fibrillar acidic protein immunoreactivities; (4) an increased thickness of the entire optic nerve and an increased area of the nerve; (5) a decreased number of nerve fibers; and (6) a decrease in the nerve fiber/meningeal membrane ratio from 3:1 to 1:1. Moreover, the amount of protein does not change with age. Therefore, the rat optic nerve appears to be sensitive to aging processes.
Dr D. Cavallotti, Department of Neurosciences, University of Rome 'La Sapienza', Rome, Italy
Classification:
2.15 Optic nerve (Part of: 2 Anatomical structures in glaucoma)
