Title: Histochemical, immunohistochemical and behavioural demonstration of the potential of Zingerone to ameliorate cognitive decline in animal model

Abstract

AbstractBackgroundScientific evidence has revealed that dementia, cognitive impairment and Alzheimer’s disease (AD) is associated with increased oxidative stress and neuroinflammation leading to neurodegeneration. Zingerone has strong antioxidant and anti‐inflammatory potentials linked to possible neuroprotective effect.This study is to determine the modulatory mechanism of zingerone in cadmium induced cognitive decline by assessing memory using novel object recognition text, neuroinflammation biomaker‐ IL‐6, TNF‐alpha, Glial fibrillary acidic Protein (GFAP) in the PFC.MethodsThirty (30) adult male Wistar rats used were grouped into six (6) groups, n = 5 as follows; Control group (A), AD model was given 5mg/kg of cadmium for seven days (B), 100mg/kg of zingerone (C) for 14 days, the treatment study groups D‐F were given 5mg/kg of cadmium for seven days and treated using varying dose of zingerone for 14 days (50mg. 100mg and 200mg). Neurobehavioral test for memory and learning done using Novel object recognition. Left prefrontal cortices were homogenized for neuroinflammatory biomaker‐ (IL‐6) and (TNF‐alpha). Fixed prefrontal cortices were processed and stained using histological stain and immunohistochemical stain for astrocytes using glial fibrillary acidic protein (GFAP). Behavioral test data were analyzed using ANOVA, post hoc test and significance set at p<0.05.ResultsZingerone effectively reversed cadmium induced cognitive decline characterized by reduced discrimination index, a marked increase in neuro‐inflammatory biomaker (IL‐6 and TNF‐α). However 200mg/kg of zingerone had a significance effect as compare to the two doses. Zingerone significantly downregulated GFAP expression activities and reduced neuronal cell loss the PFC.ConclusionZingerone potential to repair cognitive impairment is associated with modulation of neuroinflammatory biomakers that result in improved cognitive function in the PFC.