Morphometric analysis of the diameter and g-ratio of the myelinated nerve fibers of the human sciatic nerve during the aging process
| Autor: | Ivan Jovanović, Rade Cukuranovic, Braca Kundalić, Sladjana Ugrenović, Vladisav Stefanovic, Ljiljana Vasović |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Adult
0301 basic medicine Aging Adolescent Myelinated nerve fiber Nerve fiber Nerve Fibers Myelinated Nerve conduction velocity Young Adult 03 medical and health sciences 0302 clinical medicine Atrophy medicine Humans Child Process (anatomy) Aged Aged 80 and over Chemistry General Medicine Anatomy Middle Aged medicine.disease Sciatic Nerve Nerve Regeneration 030104 developmental biology medicine.anatomical_structure Morphometric analysis Ageing Sciatic nerve 030217 neurology & neurosurgery |
| Zdroj: | Anatomical Science International. 91:238-245 |
| ISSN: | 1447-073X 1447-6959 |
| Popis: | Myelinated nerve fibers suffer from different degrees of atrophy with age. The success of subsequent regeneration varies. The aim of this research was to analyze myelinated fibers of the human sciatic nerve during the aging process. Morphometric analysis was performed on 17 cases with an age range from 9 to 93 years. The outer and inner diameter of 100 randomly selected nerve fibers was measured in each of the cases evaluated, and the g-ratio (axonal diameter/outer diameter of the whole nerve fiber) of each was calculated. Scatter plots of the diameters and g-ratios of the analyzed fibers were then analyzed. Nerve fibers of each case were classified into three groups according to the g-ratio values: group I (g-ratio lower than 0.6), group II (g-ratio from 0.6 to 0.7) and group III (g-ratio higher than 0.7). Afterwards, nerve fibers of group II were further classified into small and large subgroups. The percentages of each group of nerve fibers were computed for each case and these values were used for correlational and bivariate linear regression analysis. The percentage of myelinated nerve fibers with large diameter and optimal g-ratio of the sciatic nerve declines significantly with age. This is accompanied by a simultaneous significant increase in the percentage of small myelinated fibers with g-ratio values close to 1 that occupy the upper left quadrant of the scatter plot. It can be concluded that aging of the sciatic nerve is associated with significant atrophy of large myelinated fibers. Additionally, a significant increase in regenerated nerve fibers with thinner myelin sheath is observed with age, which, together with the large myelinated fiber atrophy, might be the cause of the age-related decline in conduction velocity. A better understanding of the changes in aging peripheral nerves might improve interpretation of their pathological changes, as well as comprehension of their regeneration in individuals of different age. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink