Histological and immunohistochemical alterations in the brain tissues induced by the subchronic toxicity of gold nanoparticles: In vivo study.

BackgroundGold nanoparticles (Au NPs) have emerged as major contributors for innovative technologies and have been used extensively in various biomedical and industrial fields with little, if any, known about their neurotoxicity.ObjectiveThe current study aims to explore the nanotoxicity of Au NPs on the brain tissues.Materials and methodsTwo experimental groups, a control one and an Au NPs-treated group, each comprising 10 adult male Wistar albino rats, were used. Nanoparticle-treated rats received 28 intraperitoneal injections of 10 nm Au NPs at a daily dosage of 2 mg/kg.ResultsBrain tissue specimen for each rat under study was subjected to histological, immunohistochemical, and morphometric examination for alterations that might be induced by Au NPs exposure. Compared with control animals, brain tissue of rats treated with Au NPs exhibited neuronal shrinkage and pyknosis, perineuronal spacing, glial cell proliferation, vascular congestion, and neurons with lipofuscin pigmentation. Moreover, the hippocampus exhibited shrunken neurons, vascular congestion, and perivascular edema. Furthermore, the cerebellum showed degenerated Purkinje cells, cerebellar congestion, and perivascular spacing. In addition, the neuronal tissue demonstrated decreased autophagy, astrogliosis, and apoptosis presented by substantially decreased immunohistochemical protein expression of Beclin 1, increased expression of GFAP and caspase 3, respectively.ConclusionThe findings suggest that exposure to Au NPs has the potential to cause histological, immunohistochemical, and morphometric changes in brain tissue, which could impact the function of this vital organ. Further endeavors are necessary for more understanding of the potential risks of Au NPs to human health.