Research Paper: Effects of Aloe Vera Gel Extract on Aging-Associated Histological Changes of the Sciatic Nerve

Introduction: Prior qualitative and quantitative studies have reported morphological changes that occur in nerve fibers and non-neuronal cells of peripheral nerve during the lifetime of the rats. Previous studies suggest that Aloe Vera has some beneficial and therapeutic effects such as anti-oxidant effects. In the current study, we have evaluated histological and histomorphometric changes of Sciatic nerve in aged rats treated with Aloe Vera gel extract. Methods: Sixty healthy male albino Sprague-Dawley rats weighing 200-250 g were randomly divided into two groups: control (normal diet), and experimental group (normal diet+Aloe Vera extract). Rats of the experimental group received 400 mg/kg Aloe Vera extract daily. Within 16, 20 and 24 months, animals were anesthetized with sodium thiopental (40 mg/kg) via IP injection. After removal of Sciatic nerve on the left side, nerve dissected and fixed in 4% glutaraldehyde, post fixed in osmium tetroxide 1%, dehydrated and then embedded in TAAB resin. Thin sections (1 μm) were stained with toluidine blue stain and ten slides were obtained from each animal and got examined on light microscope. Masson’s trichrome stain was used to evaluate the development of fibrosis. Histomorphometric and histologic criteria on Sciatic nerve were determined and data were recorded. Data were analyzed using SPSS software.  Results: Results of the current study confirmed accumulation of collagen in the perineurium by aging. Our data suggested that aging caused a decrease in diameter of nerve trunk and nerve fibers, thickness of myelin and nerve fiber area. The nerve fascicle diameter decreased in the control group, only. The numbers of myelinated fibers with enfolding into the axoplasm and out folding, irregularity of nerve fibers, myelin sheath with unclear boundaries and alteration in myelin compaction were also increased. Treatment with Aloe Vera gel prevented nerve trunk, as well as fiber and myelin thickness changes. Conclusion: In the current study, we observed some alterations in sciatic nerve caused by aging, such as accumulation of collagen in perineurieum and endoneurieum. Also, a significant decrease was seen in nerve fibers,nerve trunks diameter and myelin thickness which were highly evident in rats of the 24 months age group. Treatment with Aloe vera gel extract improved histological changes and retarded neuropathy signs, significantly.