Effects of volatile organic compounds and carbon monoxide mixtures on learning and memory, oxidative stress, and monoamine neurotransmitters in the brains of mice

In this study, we investigated the effect of inhaled mixtures of volatile organic compounds (VOCs) and carbon monoxide (CO) on neuroethology. Fifty 6-week-old male Kunming mice were exposed in five similar static chambers; zero (control) and four different doses of VOC and CO mixtures (G1–G4) for 10 consecutive days and 2 h/day. The compounds and concentrations were as follows: formaldehyde, benzene, toluene, xylene, and CO as 0.10 + 0.11 + 0.20 + 0.20 + 10.00 mg/m3, 0.20 + 0.22 + 0.40 + 0.40 + 20.00 mg/m3, 1.00 + 1.10 + 2.00 + 2.00 + 100.00 mg/m3, and 5.00 + 5.50 + 10.00 + 10.00 + 500.00 mg/m3, respectively, which corresponded to 1, 2, 10, and 50 times the indoor air quality standard in China. Morris water maze and grip strength tests were performed during the exposure experiment. One day following the final exposure, oxidative damage levels, monoamine neurotransmitters, monoamine oxidase (MAO), and morphology of mice brain were analyzed. Escape latency, dopamine, norepinephrine (NE), and serotonin decre...