Assessment of the neuroprotective effect of selenium-loaded chitosan nanoparticles against silver nanoparticles-induced toxicity in rats.

BACKGROUND: With the recent growth in the applications of silver nanoparticles (Ag-NPs), worries about their harmful effects are increasing. Selenium plays a vital role in the antioxidant defense system as well as free radical scavenging activity. OBJECTIVES: This study aims to inspect the neuroprotective effect of selenium-loaded chitosan nanoparticles (CS-SeNPs) against the adverse impact of Ag-NPs on brain tissue in adult rats. DESIGN: Rats were divided into four groups: group I (control) was administered distilled water (0.5 mL/kg), group II was administered Ag-NPs (100 mg/kg), group III was administered Ag-NPs (100 mg/kg) and CS- SeNPs (0.5 mg/kg) and group IV received only CS- SeNPs (0.5 mg/kg) daily by oral gavage. After 60 days, rats were subjected to behavioral assessment and then euthanized. Brain tissues were obtained for estimation of total antioxidant capacity (TAC), malondialdehyde (MDA), 8-hydroxy-2-deoxy Guanosine (8-OHdG), and Nuclear Factor Erythroid 2 Like Protein 2 (Nrf2). Also, histological examination of the brain and immunohistochemical detection of glial fibrillary acidic protein (GFAP) were investigated RESULTS: exposure to Ag-NPs induced marked neurotoxicity in the brain tissue of rats that was manifested by decreased levels of TAC and Nrf2 with increased levels of MDA and 8-OHdG. Also, various pathological lesions with an increase in the number of GFAP immunoreactive cells were detected. While brain tissue of rats received Ag-NPs plus CS-SeNPs group (III) revealed significantly fewer pathological changes. CONCLUSION: Co-administration of CS-SeNPs significantly ameliorates most of the Ag-NPs-induced brain damage.

Ameliorative effect of Nigella sativa oil and vitamin C on the thyroid gland and cerebellum of adult male albino rats exposed to Monosodium glutamate (histological, immunohistochemical and biochemical studies).

Monosodium glutamate (MSG) is a major taste enhancer that is used as a food additive. Vitamin C (Vit C) and Nigella sativa oil (NSO) are known for their potent antioxidant activities. OBJECTIVE: This study investigates the adverse effect of MSG on the thyroid gland and cerebellum of adult male albino rats and the protection against MSG-mediated toxicity provided by Vit C and NSO. DESIGN: Fifty rats were divided into five groups that were treated via oral gavage. Group I (control) rats received distilled water, Group II rats were treated with MSG (6 mg/gm body weight/day), Group III rats were treated with MSG and Vit C (100 mg/kg body weight /day), Group IV rats were treated with MSG and NSO (50 mg/kg body weight two times per week), and Group V rats were treated with MSG together with both Vit C and NSO with MSG. After 60 days of treatment, rats were euthanized and histological sections were prepared from the thyroid gland and the cerebellum for routine staining and immunohistochemical detection of glial fibrillar acidic protein (GFAP), Caspase-3 and proliferating cell nuclear antigen (PCNA), respectively. Cerebellar tissue was also evaluated to determine glutathione (GSH) and malondialdehyde (MDA) levels; GSH was also measured in thyroid tissue. Serum levels of fT3, fT4 and TSH (thyroid stimulating hormone) were also evaluated. RESULTS: Microscopic examination of cerebellar tissues revealed significant cerebellar injury and cellular apoptosis among the rats in Group II. The thyroid glands of Group II rats were notable for degenerating follicles, loss of colloid, sloughed follicular cells and congested blood vessels. The cerebellar and thyroid tissues from rats in treatment Groups III, IV and V revealed significantly less pathology. Cerebellar and thyroid tissues from Group II rats that were treated with MSG alone revealed intense GFAP and caspase-3 (cerebellar) and PCNA (thyroid) immunoreactivity. Furthermore, cerebellar tissues from rats received MSG alone (Group II) were notable for decreased levels of GSH and increased levels of MDA; thyroid tissue from rats in Group II also demonstrated decreased levels of GSH. Likewise, serum fT3 and fT4 levels were significantly decreased, while serum TSH was significantly increased among rats in Group II. Combined administration of Vit C and NSO together with MSG (Group V) revealed some variations in oxidative parameters compared to those in the Group I control rats. CONCLUSIONS: Oral intake of MSG resulted in degenerative changes in neurons and astrocytes in cerebellum and, also degeneration of the thyroid glands of albino rats. Concomitant administration of Vit C and NSO may limit MSG-induced damage to the cerebellum and thyroid glands and thereby provide significant protection against the oxidative damage induced by MSG.