A study of heart and blood of rodents inhaling diesel engine exhaust particulates

The in vivo effects of inhalation of diesel engine exhaust (DEE) were evaluated in 128 rats and 146 guinea pigs. They were exposed in special chambers to three different dose levels of DEE particulates; 250, 750, and 1500 μg/m 3, for 20 hr/day and 5.5 days/week. Rats were sacrificed after 13, 16.7, 25.7, 42, 52, and 78 weeks exposure, while guinea pigs were sacrificed after 6, 13, 17, 26, 42, 52, and 78 weeks exposure. Each group of each species was compared to its own age-matched control group. Morphometric analysis of the heart revealed no significant alterations in mass which could be assigned to inhalation of DEE at any dosage level or duration of exposure in either species. This included an assessment of the relative wet weights of the right ventricle, left ventricle, combined ventricles, combined atria, and ratio of right to left ventricle weights. Likewise, hematology was not changed in either species at any dosage level or duration of exposure by inhalation of DEE.