Effect of Cadmium Exposure and Annona muricata (Soursop) Leaf Extract on the Cortical Histology of Adult Albino Rats

Abstract

This study investigated the effect of cadmium exposure and Annona muricata (soursop) leaf extract on the cortical histology of adult albino rats. Cadmium is a recognised environmental toxicant capable of inducing neurodegeneration through oxidative stress and inflammatory pathways, while Annona muricata is a medicinal plant rich in bioactive compounds with reported antioxidant and neuroprotective properties. Fifty (50) adult albino rats weighing 100-130 g were acclimatised for two weeks and randomly divided into five groups (A-E), with ten rats in each group. Group A served as the control, Group E received cadmium only (0.5 mg/kg), while Groups B, C, and D received cadmium (0.5 mg/kg) combined with low (200 mg/kg), medium (400 mg/kg), and high (800 mg/kg) doses of Annona muricata leaf extract, respectively. All administrations were carried out orally for two weeks using an oral gavage technique. At the end of the experimental period, the animals were sacrificed under chloroform anaesthesia, and cortical tissues were harvested, fixed in 10% formol saline, and processed using standard histological techniques. Sections were stained with haematoxylin and eosin and examined under a light microscope. The results revealed normal cortical histology in the control group, while cadmium-only exposure induced inflammatory cell aggregation. The low-dose Annona muricata group exhibited severe fibrosis, whereas the medium- and high-dose groups showed restoration of normal cortical histoarchitecture. These findings suggest that cadmium induces cortical damage, while Annona muricata exhibits dose-dependent neuroprotective effects, with higher doses reversing cadmium-induced histopathological alterations in the cerebral cortex of adult albino rats.