Neuroprotective effect of grape seed extract against the histopathological changes of the cerebral cortex of adult albino rats induced by aluminum chloride

ABSTRACT

Aluminum [Al.] is a neurotoxic metal and its exposure may be a factor in the etiology of various neurodegenerative diseases. Recently, a great awareness about the role of Al. in Alzheimer's disease [AD], which demonstrated increasing prevalence of AD in areas with relatively high content of Al. in drinking water. This experimental study tried to identify the histopathological changes induced by aluminum chloride and the possible protective role of grape seed extract against its neurotoxicity using histological and immuno-histochemical study. Material and In this study, 35 adult albino rats were used. The rats were divided into two main groups; control and experimental groups. 9 rats were used as a control group [group I]. The experimental group [group II]; consisted of 26 rats, which were equally subdivided into 2 subgroups; Subgroup [IIa]; each animal received aluminum chloride 100mg/kg.b.wt/day orally for 9 weeks and Subgroup [IIb]; each animal received the same dose of aluminum chloride with concomitant administration of 50mg/kg.b.wt./day grape seed extract orally for 9 weeks. Specimens of the cerebral cortex of the control and experimental groups were taken and prepared for histological and immuno-histochemical examinations. The differently stained sections of the subgroup [IIa] revealed that aluminum chloride induced obvious neuronal damage, where the cortical layers appeared disorganized. The most characteristic pathological feature was the necrosis of the pyramidal cells and appearance of neurofibrillary tangles in their cytoplasm with disappearance of the glutathione reductase enzyme from the cytoplasm of the damaged neurons. The neuropil appeared edematous with dilated blood capillaries containing amyloid collection. On the other hand, addition of grape seed extract in subgroup [IIb] alleviates the deleterious effects of aluminum chloride, where the cortical layers appeared organized with apparently normal blood capillaries. Many pyramidal cells appeared normal with central nuclei and basophilic cytoplasm. However, the neuropil appeared edematous. The immuno-histochemical stain showed reappearance of the+ve reaction to the glutathione reductase enzyme. This experimental study tried to hypothesize that aluminum chloride administration induces histopathological changes, which might be involved in the pathogenesis of AD. It also identified the protective role of grape seed extract against the Al induced neurotoxicity