title: Inhalation of diesel engine exhaust increases bone mineral concentrations in growing rats.
abstract: Experiments were conducted to determine whether diesel engine exhaust affects bone metabolism in growing rats. The rats were assigned to three groups: those exposed to total diesel engine exhaust with 5.63 mg/m3 particulate matter, 4.10 ppm nitrogen dioxide, 8.10 ppm nitrogen monoxide; those exposed to filtered exhaust without particulate matter; and those exposed to clean air. Dosing experiments were performed for 3 months beginning at birth (6 h/day for 5 days/week). Bone mineral content (BMC) values in lumbar vertebral bone were significantly increased in both groups exposed to diesel exhaust (P < 0.01) compared to that of rats exposed to clean air. Bone mineral density (BMD) values were also significantly increased in both exposed groups, total exhaust (P < 0.01) and filtered exhaust (P < 0.001), compared to that of rats exposed to clean air. BMD values in the mid-femur were also significantly greater in animals exposed to diesel exhaust, total exhaust (P < 0.05), and filtered exhaust (P < 0.01), compared to that of those exposed to clean air. Urinary excretion of deoxypyridinolines, a biochemical marker for bone resorption, was significantly reduced in animals exposed to total diesel exhaust and filtered exhaust (P < 0.001, P < 0.01) compared to control. There was also a significant difference between the two exposure groups of diesel exhaust (P < 0.05). Since these effects were not inhibited by filtration, the gaseous phase of the exhaust was considered more responsible than particulate matter for reducing bone resorption.
authors.affiliation: Department of Environmental Health, Toyko Metropolitan Research Laboratory of Public Health, Shinjuku-ku, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D005260:Female; D051381:Rats; D011916:Rats, Inbred F344; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D001335:Vehicle Emissions