Age related ultrastructural changes in albino rat sciatic nerve and the effect of antioxidants

ABSTRACT

The present study was performed to clarify the age related ultrastuctural changes of the myelinated fibres in the sciatic nerve of albino rats and to elucidate the effects of receiving antioxidants on such age alterations. Thirty male albino rats were used in this investigation; 10 were adult [3- month- Old], ten were aged [24- month -old] and the last ten were aged but received vitamins C and E for 4 weeks. Then, all rats were decapitated and their sciatic nerves were rapidly dissected and toluidine blue- stained semithin sections were prepared for light microscopic examination. Ultrathin sections were processed for transmission electron microscope examination. Compared to the adults, the sciatic nerves of the aged rats possessed thinner perineurium. The endoneurium was collagen filled and contained many fibrocytes. The myelin sheath showed thickening, invagination, evagination, heterogeneity, splitting and myelin bubbles. The cytoplasm of Schwann cells housed rough endoplasmic reticulum, mitochondria and many electron dense bodies. The axoplasm was compressed in some areas and occasionally housed membrane bound vesicles containing heterogenous granular material and low electron dense vacuoles containing myelin figures. The unmyelinated axons were present in groups burned in deep recesses on the surface of Schwann cells. The sciatic nerves of rats received vitamins C and E showed minute splitting, infolding and outfolding of the myelin sheath. In some situations, fibrocytes extended their processes and encircled the nerve fibres, despite the improvement of the condition of the myelin. The axoplasm exhibited sequestration of the degenerated parts that contained membrane bound vesicles of low electron density. Based on the previous data, it may be concluded that, age affected the myelinated fibres of the sciatic nerve and the intake of vitamins C and E lessened such influences