Quercetin Improves Cognitive Function by Ameliorating Histopathological Changes and Inflammation in Di(2-ethylhexyl)...

Background/Objectives: Phthalates are a group of organic compounds widely used for enhancement in flexibility and transparency of polyvinyl chloride (PVC) products. Exposure to phthalate-containing substances has been shown to affect brain function, particularly in learning and memory processes. Quercetin is a plant-derived flavonoid with remarkable anti-oxidant and anti-inflammatory potential. This study investigated the possible protective effects of quercetin on spatial learning and memory, histomorphometric changes, and hippocampal expression of inflammatory cytokines (TNF-α and IL-6) in male mice exposed to di(2-ethylhexyl) phthalate (DEHP). Methods: A total of 42 male mice were divided into seven groups. Quercetin was administered orally at doses of 25 and 50 mg/kg/day, either alone or in combination with DEHP (200 mg/kg/day). Following the final day of the treatment, spatial learning and memory were assessed by the Morris Water Maze test. Hippocampal tissues were sampled for Nissl, H&E, and immunofluorescence staining. Quantitative real-time PCR was used to measure the expression of TNF-α and IL-6. Results: The DEHP group exhibited significant impairments in learning and memory, neuronal damage, and cellular disorganization in the hippocampus, along with increased astrocyte activation and elevated expression of TNF-α and IL-6. On the other hand, quercetin supplementation significantly reduced these inflammatory markers and histological damages and also improved spatial learning and memory. Conclusions: Overall, quercetin improves cognitive function that is associated with attenuating astrocyte activation and inflammation.