The possible protective role of ginseng on the sciatic nerve neuropathy induced experimentally by acrylamide in adult male albino rat: a histological and morphometric study

Vitamin E and 5-amino salicylic acid ameliorates acrylamide-induced peripheral neuropathy by inhibiting caspase-3 and inducible nitric oxide synthase immunoexpression

Acrylamide is a fundamental cause of accidental toxicity in humans. This study aimed to investigate the neuroprotective effect of vitamin E (Vit. E), 5-amino salicylic acid (5-ASA), and their combination against acrylamide-induced sciatic nerve toxicity. For this purpose, 25 male Wister rats were divided into 5 groups: control, acrylamide, acrylamide + Vit. E, acrylamide + 5-ASA, and acrylamide + Vit. E + 5-ASA. Food intake and body weight were assessed after 7 days. Furthermore, the gait score was also evaluated for each rat. The sciatic nerve was dissected, fixed, and processed for routine light and electron microscopic examination. Haematoxylin and eosin, osmium tetroxide for myelin sheath, and toluidine blue for semithin section were used. In addition, immunohistochemistry for caspase-3 and inducible nitric oxide synthase (iNOS) were performed. The results showed reduced food intake and body weight in acrylamide rats. Abnormal gait score was also recorded in acrylamide rats with significant improvement in Vit. E, and Vit. E + 5-ASA groups. Histologically, Vit. E and 5-ASA provided potential protection against decreased sciatic nerve axon density, disrupted myelination, and the alteration in the immunohistochemistry induced by acrylamide. Vit. E and its combination with 5-ASA provided more evident protection compared to 5-ASA alone. 5-ASA significantly decreased apoptotic cell death (caspase-3 immunoexpression) while Vit. E failed. Both Vit. E and 5-ASA significantly decreased iNOS immunoexpression in the sciatic nerve, where 5-ASA was superior to Vit. E. These findings concluded that both Vit. E and 5-ASA protect against acrylamide-induced peripheral neuropathy through downregulation of both caspase-3 and iNOS immunoexpression.

Apoptosis and astrogliosis perturbations and expression of regulatory inflammatory factors and neurotransmitters in acrylamide-induced neurotoxicity under ω3 fatty acids protection in rats

This study was aimed to investigate the potential ameliorative effects of omega-3 (ω3) fatty acids against acrylamide (ACR)-induced neurotoxicity. Thirty-two adult male Sprague Dawley rats were randomly assigned into four groups (n = 8) as follows: control, ω3 fatty acids (1000 mg/kg bwt/day orally), ACR-treated (50 mg/kg bwt/day IP) and ACR plus ω3 fatty acids group. Treatments were performed every other day for 21 consecutive days. ACR induced abnormal gait and elevated serum levels of proinflammatory cytokines (IL-6 and TNF-α), brain and spinal cord MDA levels and decreased brain and spinal cord GSH levels. Moreover, it reduced neurotransmitters (acetylcholine, GABA, serotonin and noradrenaline levels) and increased AChE activity in brain tissues. Histopathologically, ACR caused various degenerative changes, necrosis and glial cell activation in the cerebrum, cerebellum, hippocampus, spinal cord and sciatic nerve. Likewise, the histomorphometric analysis was constant with ACR-induced neurotoxicity. The ACR induced axonal atrophy and myelin disruption and decreased g-ratio of the sciatic nerve. Immunohistochemically, strong positive expressions of apoptotic marker caspase-3 and astroglial GFAP in the examined tissues were detected. Contrariwise, concurrent administration of ω3 fatty acids partially attenuated ACR impacts, as it improved the gait performance, reduced oxidative stress and pro-inflammatory cytokines, and modulate the levels of the neurotransmitters. It also ameliorated the intensity of ACR-induced histopathological and histomorphometric alterations within the examined nervous tissues. It could be concluded that ω3 fatty acids have antioxidant, anti-inflammatory and anti-apoptotic potentials against ACR neurotoxicity via suppression of oxidative stress, lipid peroxidation and pro-inflammatory cytokines, and inhibition of AChE activity and downregulation of caspase-3 and GFAP expressions in the nervous tissues.

Effect of long term-administration of aspartame on the ultrastructure of sciatic nerve

Aspartame is the most widely used artificial sweetener worldwide. There is much controversy about the effect of aspartame on different cells in the body. The aim of this study was to evaluate the effect of aspartame on the structure of the sciatic nerve. Thirty adult male albino rats were divided into three groups. Group I served as control; Group II received aspartame orally in a dose of 250 mg/kg/d for 3 months; Group III received aspartame at the same dose and for the same period, and was allowed to recover for 1 month. Specimens of sciatic nerve were processed, and semithin and ultrathin sections were examined by light and electron microscopy. A morphometric study was done to evaluate the g-ratio, which is the ratio between the axon diameter and total fiber diameter. Long-term aspartame administration resulted in many degenerative changes affecting mainly the myelin sheath, in the form of focal and extensive demyelination; disruption and splitting of myelin lamellae with loss of compact lamellar structure; and excessive enfolding with irregular thickening of myelin sheaths. Less frequent than those observed in the myelin sheath, some axonal changes were detected, such as compression and distortion. Dilated rough endoplasmic reticulum and vacuolation of the cytoplasm of Schwann cells were also detected. Partial improvement was observed in the recovery group. It was concluded that long-term administration of aspartame had a harmful effect on the structure of sciatic nerve and 1 month stoppage of aspartame was not enough to achieve complete recovery.