Resveratrol Attenuates Neuroinflammation and Gut-Brain Axis Dysfunction Induced by Lead and Cadmium Co-Exposure by Modulating Gut Microbiota in Rats.

Resveratrol (RSV), a dietary polyphenol widely present in traditional medicinal plants and foods, exhibits antioxidant and anti-inflammatory properties that are relevant to ethnopharmacological strategies for protecting against environmental neurotoxicants. Given increasing real-world co-exposure to lead (Pb) and cadmium (Cd), elucidating RSV's capacity to preserve gut-brain axis (GBA) homeostasis has direct translational relevance for populations relying on phytochemical interventions. Sprague-Dawley rats were randomized into control, Pb-Cd model, and RSV treatment groups (10, 20, or 40 mg/kg). For 4 weeks, rats received Pb (300 mg/L) and Cd (50 mg/L) in drinking water with daily RSV. Cognitive function was assessed by Morris water maze; barrier integrity by Evans blue assay, histology, and Western blot for ZO-1/Occludin; synaptic ultrastructure by TEM; microbiota composition by 16S rRNA sequencing; and short-chain fatty acids (SCFAs) by GC-MS. Neurotransmitters (5-HT, GABA, SP, VIP) and cytokines (IL-6, IL-1β, TNF-α) were measured by ELISA. RSV improved spatial learning, reduced EB extravasation, preserved synaptic ultrastructure and proteins (BDNF, SYN, PSD-95), and restored intestinal architecture with increased ZO-1/Occludin. RSV attenuated cytokine release, normalized goblet cells, reversed dysbiosis by restoring Lactobacillaceae/Prevotellaceae, and increased acetate, propionate, and butyrate. It reinstated 5-HT and GABA while reducing SP and restoring VIP across serum, colon, and hippocampus. RSV attenuated Pb-Cd-associated neurotoxicity and was accompanied by improved intestinal and BBB-related readouts, partial normalization of gut microbiota features and SCFA levels, and preservation of synaptic and neurotransmitter-related markers, consistent with a link to gut-brain axis function. This study is among the first to test RSV in a Pb-Cd co-exposure model using a multi-dose regimen with integrated behavioral, barrier, microbial, and neurochemical endpoints.