Potential mechanisms of neurobehavioral disturbances in mice caused by sub-chronic exposure to low-dose VOCs

Abstract

To investigate effects of neurobehavioral disturbances in mice caused by sub-chronic exposure to low-dose volatile organic compounds (VOCs) and the possible mechanism for these effects, 60 male Kunming mice were exposed in 5 similar static chambers, 0 (control) and 4 different doses of VOCs mixture (G1-4) for consecutively 90 d at 2 h/d. The concentrations of VOCs mixture were as follows: formaldehyde, benzene, toluene, and xylene 0.05 + 0.05 + 0.10 + 0.10 mg/m(3), 0.10 + 0.11 + 0.20 + 0.20 mg/m(3), 0.50 + 0.55 + 1.00 + 1.00 mg/m(3), 1.00 +1.10 + 2.00 + 2.00 mg/m(3), respectively, which corresponded to 1/2, 1, 5, and 10 times of indoor air quality standard in China. Morris water maze (MWM) and Grip strength (GS) test were performed in the last 7 weeks. One day following VOCs exposure, oxidative stress markers, neurotransmitters, and cholinergic system enzymes in brain were examined. In addition, the expressions of N-methyl-d-aspartate (NMDA) receptor in hippocampus were determined. VOCs exposure induced behavioral impairment of mice in MWM and GS test. The levels of reactive oxygen species (ROS), malondialdehyde (MDA) and glutamic acid (Glu) were significantly increased, while the acetylcholinesterase (AChE), choline acetyltransferase (ChAT) and acetylcholine (ACh) levels, and the expression of NMDA receptor were significantly decreased in VOCs exposed groups. Results showed that sub-chronic exposure to low-dose VOCs induced damage on physique and motor function, as well as impairment on learning and memory capacity of mice. Oxidative damage, abnormal metabolism of neurotransmitters and cholinergic system enzymes, and the alternation of NMDA receptor expression may be the possible mechanism for VOCs-induced neurotoxicity.

Effects of triclosan on acute toxicity, genetic toxicity and oxidative stress in goldfish (<i>Carassius auratus</i>)

“…T-AOC was significantly decreased in the 0.5596 mg/l (1/2 LC 50 ) TCS exposure group, suggesting an imbalance between ROS and antioxidant defenses. MDA is a product of lipid peroxidation, which can be used to evaluate the oxidative damage in lipids [ 24 , 37 ]. In the present study, the MDA levels in the livers of goldfish exposed to 0.2798 (1/4 LC 50 ) and 0.5596 mg/l (1/2 LC 50 ) TCS were significantly increased compared with that of the solvent control.…”

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

“…Moreover, learning and memory impairment occurred in short-term CO exposure mice (Hiramatsu and Inoue, 2000). Our previous studies have also demonstrated that VOCs mixture inhalation affected learning and memory performances (Li et al, 2012; Wang et al, 2014).…”

“…The neurotoxic effects of individual VOC have been confirmed (Huerta-Rivas et al, 2012). Our previous studies have also demonstrated that these mixtures of VOCs have effects on the nervous system of mice (Li et al, 2012; Wang et al, 2014).…”

“…Detailed procedures about MWM and detection methods of learning and memory in mice were performed as per established protocols (Wang et al 2014). In brief, the water maze analysis system consisted of a circular pool, escape platform, cameras, computers, etc.…”

“…The grip strength (GS) meter allows the study of neuromuscular functions in rodents. Oxidative stress, defined as a disturbance in the pro-oxidant–antioxidant balance in favor of the former, plays a crucial role in neurotoxicity (Li et al, 2012; Lu et al, 2008; Wang et al, 2014). Previous study confirmed depressive disorder was associated with disturbances of brain monoamine neurotransmitters (Bortolato et al, 2013).…”