Retardation of the age-related increase in spontaneous cortical spike-wave discharges (SWD) in rats after a 28-day inhalation (SWD) in rats after a 28-day inhalation exposure to an industrial solvent, pseudocumene (1,2,4-trimethylbenzene).
It has been hypothesized that exposure to neurotoxins may hasten the process of brain ageing. Volatile hydrocarbons are in common use as solvents and their neurotoxic properties are acknowledged. In the rat, the age-related neurodegenerative changes in the brain develop together with an increased occurrence of bursts of spontaneous spike-wave discharges (SWD) in the neocortex. Therefore, the number and/or duration of SWD bursts may serve as an index allowing to distinguish between young and old brains (7). Measuring the SWD activity after exposure may thus reveal the effect of the studied neurotoxicant on brain ageing. Pseudocumene (1,2,4-trimethylbenzene, TMB), is a component of industrial solvent mixtures. The present study investigated the effect of a 4-week (6h/day, 5 days/week) inhalation exposure to TMB at concentrations of 0, 25, 100 or 250 ppm on the occurrence of SWD bursts. EEG recordings were performed before and one day, 30 days and 4 months after exposure. In rats exposed to TMB at 0 and 25 ppm, the level of the SWD activity increased progressively after exposure. In rats exposed to TMB at 100 or 250 ppm, the SWD activity did not increase during the post-exposure period or even dropped below the pre-exposure level. This result indicates that the persistent changes in the rat central nervous system (CNS), following the exposure to TMB, differ in some respects from those which develop in the course of normal ageing.
Gralewicz
S
S
Department of Toxicity and Carcinogenesis, The Nofer Institute of Occupational Medicine, Lódź, Poland.
Wiaderna
D
D
Tomas
T
T
D000280:Administration, Inhalation; D000375:Aging / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D001555:Benzene Derivatives / Q000633:toxicity*; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D004569:Electroencephalography / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D001555:Benzene Derivatives; C010313:pseudocumene