Prefrontal cortical morphology of nickel chloride induced toxicity following the administration of Moringa oleifera aqueous extract

Abstract Introduction and Aim: Heavy metal exposure, particularly to nickel chloride (NiCl₂), poses significant health risks due to its neurotoxic effects, especially on the prefrontal cortex (PFC), a critical region for cognition and decision-making. NiCl₂ induces oxidative stress, neuronal damage, and inflammation, necessitating effective therapeutic interventions. Moringa oleifera, known for its antioxidant and neuroprotective properties, is a promising natural remedy. This study aimed to investigate the effects of NiCl₂-induced toxicity on PFC morphology in Wistar rats and evaluate the ameliorative potential of M. oleifera aqueous extract. Methodology: Twenty-five adult male Wistar rats were divided into five groups (n=5): normal control (food and water), NiCl₂-untreated (20 mg/kg NiCl₂), M. oleifera-only (2500 mg/kg), NiCl₂ + 1250 mg/kg M. oleifera, and NiCl₂ + 2500 mg/kg M. oleifera, all administered orally for 14 days. Body weights were recorded, and PFC tissues were harvested for histological (H&E), Nissl (Cresyl Fast Violet), and immunohistochemical (GFAP) analyses. Data were analysed using one-way and two-way ANOVA with post-tests (p<0.05). Results: NiCl₂ exposure reduced body weight and induced PFC neuronal degeneration, inflamed blood vessels, intense Nissl staining, and astrogliosis, indicating neurotoxicity. M. oleifera-only group showed normal PFC morphology. Groups treated with M. oleifera (1250 mg/kg) exhibited improved neuronal integrity and reduced inflammation, while the 2500 mg/kg group showed partial vascular enlargement and severe astrogliosis. No significant body weight differences were observed. Conclusion: NiCl₂ induces significant PFC neurotoxicity, which M. oleifera, particularly at 1250 mg/kg, mitigates by preserving neuronal structure and reducing inflammation, likely via antioxidant mechanisms. Higher doses (2500 mg/kg) may be less effective due to increased astrogliosis. M. oleifera holds therapeutic potential for heavy metal-induced neurotoxicity, warranting further dose optimisation studies.