Histological and Immunohistochemical Study of the Effect of Zinc Oxide Nanoparticles on the Adult Male Albino Rat`s Cerebellar Cortex and the Potential Ameliorative Effect of Mesenchymal Stem Cells derived from Bone Marrow

Introduction: One of the most widely utilized metal oxides globally is zinc oxide nanoparticles (ZnONPs). The human exposure to ZnONPs has increased, generating worries about their potential toxicities. Recently, bone marrow-derived mesenchymal stem cells (BM-MSCs) have been proposed as a therapy option for a number of illnesses, including neurological conditions. Aim of the work: To study the effect of ZnONPs on the adult male albino rats’ cerebellar cortex and the potential ameliorative effect of BM-MSCs.Material and Methods: 65 adult male albino rats were used in this study, 5 of them were used as a source of BM-MSCs and others were divided into: group I (control group), group II (ZnoNPs treated group) subdivided into two subgroups (IIa&IIb received 50 mg/Kg of ZnONPs intraperitoneally (IP) for 14 days & 28 days respectively) and group III (ZnONPs&BM-MSCs treated group) subdivided into two subgroups (IIIa&IIIb received ZnONPs as subgroups IIa&IIb respectively then was once intravenous (IV)injected with BM-MSCs 24 hours after the last dose of ZnONPs). Then, histological, immunohistochemical, electron microscopy, and morphometric investigations were studied on cerebellar specimens. Results: Alterations in the cerebellar cortex structure of subgroups IIa and IIb such as pericellular halos surrounding all nerve cells and absence of Purkinje cells leaving empty spaces. Electron microscopic examination showed mitochondria with distorted cristae and vacuolated cytoplasm in most of nerve cells especially Purkinje cells. Group IIb showed more severe histological changes than group IIa. These alterations were significantly ameliorated in the subgroups treated with stem cells. Conclusion: ZnONPs caused unfavourable changes to the histological structures of the adult male albino rats` cerebellar cortex. These changes were exaggerated with increasing period of ZnONPs administration which could be ameliorated by injecting BM-MSCs. Key words: ZnONPs, cerebellar cortex, BM-MSCs, GFAP.