Neurotoxicity of continuous (90 days) inhalation of technical grade methyl butyl ketone in hens.
Abdo-KM; Graham-DG; Timmons-PR; Abou-Donia-MB
J Toxicol Environ Health 1982; 9(2):199-215
The neurotoxic effects of chronic inhalation of methyl-butyl-ketone (591786) (MBK) were investigated in hens. Leghorn-hens were exposed continually for 90 days to various concentrations of MBK, containing 70 percent methyl-n-butyl-ketone (591786) (MnBK) and 30 percent methyl-isobutyl-ketone (108101) (MiBK), in an inhalation chamber. Hens were examined every other day for up to 120 days for signs of neurotoxicity, including ataxia. The spinal cord and the sciatic, peroneal, and tibial nerves were histopathologically examined in hens that died or were sacrificed during or after the experiment. Weight losses compared to controls were also assessed. Atmospheres of 50, 100, 200, or 400 parts per million (ppm) MBK produced neurotoxic symptoms. The onset, severity, and progression of the symptoms were dependent on dose and duration of exposure. Hens exposed to 200 or 400ppm MBK developed ataxia and paralysis and died or were sacrificed before the 90 day exposure schedule was completed. At 100ppm, hens developed severe ataxia, and most had no changes in clinical symptoms during the 30 day postexposure observation period. At 50ppm, hens had gross ataxia at day 90 and had partial regression of neurological loss after termination of exposure. Hens exposed to 10ppm developed no abnormal symptoms. Only hens exposed to 200 and 400ppm MBK had significant weight loss. Some hens from groups exposed to 50 to 400ppm MBK had marked histopathological changes in the spinal cord and peripheral nerves. These changes included excessive swelling, phagocytosis, degeneration, and demyelination of the axons, and the degree of changes depended on the dose and duration of exposure. The authors conclude that the neurotoxic effect of subchronic continuous inhalation of MBK is concentration dependent, and they attribute the neurotoxic effect to MnBK.
JTEHDL; NIOSH-Publication; NIOSH-Grant; Solvents; Animal-studies; Toxicology; Nervous-system-disorders; Neurotoxicity; Neuromotor-disorders; Histology; Chronic-toxicity
Pharmacology Duke University Department of Pharmacology Durham, N C 27710
591-78-6; 591-78-6; 108-10-1
Journal of Toxicology and Environmental Health
Duke University, Durham, North Carolina