Comparison of Morphometric Aspects of Light and Electron Microscopy of the Hypoglossal Nerve between Young and Aged Male Wistar Rats
Objective: Age-related changes occur in many different systems of the body. Many elderlypeople show dysphagia and dysphonia. This research was conducted to evaluatequantitatively the morphometrical changes of the hypoglossal nerve resulting from theaging process in young and aged rats.Materials and...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Royan Institute (ACECR), Tehran
2012-01-01
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| Series: | Cell Journal |
| Subjects: | |
| Online Access: | http://celljournal.org/library/upload/article/af_5665246645432342335335427536674537354333nabiollah%20soltanpour-1.pdf |
| Summary: | Objective: Age-related changes occur in many different systems of the body. Many elderlypeople show dysphagia and dysphonia. This research was conducted to evaluatequantitatively the morphometrical changes of the hypoglossal nerve resulting from theaging process in young and aged rats.Materials and Methods: Through an experimental study ten male wistar rats (4 months: 5rats, 24 months: 5 rats) were selected randomly from a colony of wistars in the UWC. Aftera fixation process and preparation of samples of the cervical portion of the hypoglossalnerve of these rats, light and electron microscopic imaging were performed. These imageswere evaluated according to the numbers and size of myelinated nerve fibers, nucleoli ofSchwann cells, myelin sheath thickness, axon diameter, and g ratio. All data were analyzedby Mann-Whitney, a non-parametric statistical test.Results: In light microscope, numbers of myelinated nerve fibers, the mean entire nerveperimeters, the mean entire nerve areas and the mean entire nerve diameters in youngand aged rats’ were not significantly different between the two groups.In electron microscope, numbers of myelinated axons, numbers of Schwann cell nucleoliand the mean g ratios of myelinated axon to Schwann cell in young and aged rats werenot significantly different. The myelinated fiber diameters, the myelin sheath thicknesses,myelinated axon diameters and the mean g ratio of axon diameter to myelinated fiberdiameter in young and aged fibers were significantly differentConclusion: The mean g ratio of myelinated nerve fibers of peripheral nerves stabilizes atthe level of 0.6 after maturation and persists without major change during adulthood. Thisratio of axon diameter to fiber diameter (0.6) is optimum for normal conduction velocity ofneural impulses. Our study indicated that the g ratio of myelinated nerve fiber of the hypoglossalnerve decreased prominently in aged rats and can be a cause of impairment innerve function in old age. Thus, prospective studies concerning electrophysiological andconductive properties of the peripheral nerve could be useful to clarify further the effectsof aging on peripheral nerves. |
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| ISSN: | 2228-5806 2228-5814 |