The effects of co‑exposure to caffeine and heavy metals on learning and oxidative stress in mice

Abstract

Caffeine, a widely consumed psychoactive substance, may affect the neurotoxicity of environmental toxins. The study aimed to investigate the effects of the combined administration of caffeine and heavy metal compounds (cadmium chloride and lead acetate) on brain tissue function, focusing on memory processes and oxidative stress parameters. Adult male Swiss mice were administered substances intraperitoneally for 10 days. A passive avoidance test evaluated long‑term memory, while the Y‑maze assessed spatial working memory. In addition, lipid peroxidation and glutathione levels, as well as superoxide dismutase, catalase, and acetylcholinesterase activity, were determined in mouse brains. The results showed that exposure to caffeine and cadmium or lead caused different neurotoxic effects. Unlike lead, cadmium interacted with caffeine in memory tests. Caffeine protected mice against cadmium‑induced spatial working memory impairment. The combination of caffeine and cadmium impaired learning in the passive avoidance test. Cadmium and lead caused oxidative stress in the brain, and caffeine had a preventive effect against it. The study showed that co‑exposure to caffeine and cadmium could affect learning and memory. The antioxidant activity of caffeine may play a protective role in cadmium‑induced spatial memory impairment.