Bioaccumulation and locomotor effects of manganese sulfate in Sprague-Dawley rats following subchronic (90 days) inhalation exposure.
Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic compound that was introduced as an anti-knock additive to replace lead in unleaded fuel. The combustion of MMT results in the emission of fine Mn particulates mainly in the form of manganese sulfate and manganese phosphate. The objective of this study is to determine the effects of subchronic exposure to Mn sulfate in different tissues, on locomotor activity, on neuropathology, and on blood serum biochemical parameters. A control group and three groups of 30 male Sprague-Dawley rats were exposed 6-h/day, 5 days/week for 13 consecutive weeks at 30, 300, or 3,000 microg/m(3) Mn sulfate. Locomotor activity was measured during 36 h using an Auto-Track System. Blood and the following tissues were collected and analyzed for manganese content by neutron activation analysis: olfactory bulb, globus pallidus, caudate/putamen, cerebellum, frontal cortex, liver, lung, testis, and kidney. Neuronal cell counts were obtained for the caudate/putamen and the globus pallidus and clinical biochemistry was assessed. Manganese concentrations were increased in blood, kidney, lung, and testis and in all brain regions in the 3,000 microg/m(3) exposure group. Significant differences were also noted in the 300 microg/m(3) exposure group. Neuronal cell counts for the globus pallidus were significantly different between the two highest exposed groups and the controls. Locomotor activity for all exposure concentrations and resting time for the middle and highest concentrations for the two night resting periods were significantly increased. Total ambulatory count was decreased significantly for all exposure concentrations. Biochemical profiles also presented significant differences. No body weight loss was observed between all groups. These results suggest that neurotoxicity could occur at low exposure levels of Mn sulfate, one of the main combustion products of MMT.
Tapin
Danielle
D
TOXHUM (Human Toxicology Research Group) and Department of Environmental and Occupational Health, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Québec, Canada, H3C 3J7.
Kennedy
Greg
G
Lambert
Jean
J
Zayed
Joseph
J
D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000378:metabolism; D002452:Cell Count; D003404:Creatinine / Q000097:blood; D005917:Globus Pallidus / Q000187:drug effects / Q000473:pathology; D019570:Inhalation Exposure; D007668:Kidney / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D017895:Manganese Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics; D009043:Motor Activity / Q000187:drug effects*; D017072:Neostriatum / Q000187:drug effects / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000097:blood; D013431:Sulfates / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D013737:Testis / Q000378:metabolism; D014018:Tissue Distribution; D036401:Toxicity Tests, Chronic / Q000379:methods; D014867:Water / Q000032:analysis
D001786:Blood Glucose; D017895:Manganese Compounds; D013431:Sulfates; D014867:Water; D012965:Sodium Chloride; D003404:Creatinine; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; C039798:manganese sulfate