Subchronic inhalation toxicity of benzene in rats and mice
A subchronic inhalation toxicity study of benzene was conducted in CD-1 mice and Sprague-Dawley rats. Four groups of animals consisting of 150 mice and 50 rats/sex each were exposed to concentrations of 1, 10, 30, and 300 ppm benzene vapor, 6 hours/day, 5 days/week, for 13 weeks. Additional groups of mice and rats, of equal size, were exposed under similar conditions to filtered air and served as control groups. Thirty mice and 10 rats/sex in each group were sacrificed after 7, 14, 28, 56, and 91 days of treatment. Criteria used to evaluate exposure-related effects included behavior, body weights, organ weights, clinical pathology, gross pathology, and histopathology. Fifty animals per sex of each species were exposed concurrently for cytogenetic studies. In addition, blood serum was obtained for immunological assays. The results of these two studies will be reported separately. No consistent exposure-related trends were seen in the clinical observations and body weight data. Exposure-related clinical pathology changes were seen in the high-level (300 ppm) animals of both species. In the mice, these changes included decreases in hematocrit, total hemoglobin, erythrocyte count, leukocyte count, platelet count, myeloid/erythroid ratios, and percentage of lymphocytes. Mean cell volume, mean cell hemoglobin, glycerol lysis time, and the incidence and severity of red cell morphologic changes were increased in the mice. In the rats, decreased lymphocyte counts and a relative increase in neutrophil percentages were the only exposure-related clinical pathology alterations. Histopathologic changes were present in the thymus, bone marrow, lymph nodes, spleen, ovaries, and testes of mice exposed to 300 ppm and in most cases the incidence and severity of the lesions were greater in the males.
- OSTI ID:
- 5074329
- Journal Information:
- Am. J. Ind. Med.; (United States), Vol. 5-6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BENZENE
TOXICITY
BONE MARROW
PATHOLOGICAL CHANGES
ERYTHROCYTES
MORPHOLOGICAL CHANGES
LYMPH NODES
OVARIES
SPLEEN
TESTES
THYMUS
AIR POLLUTION
BLOOD CELLS
BLOOD COUNT
CHRONIC EXPOSURE
COMPARATIVE EVALUATIONS
DOSE-RESPONSE RELATIONSHIPS
HEMOGLOBIN
INHALATION
LYMPHOCYTES
MICE
PATHOLOGY
RATS
SEX DEPENDENCE
WEIGHT
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
AROMATICS
BIOLOGICAL MATERIALS
BLOOD
BODY
BODY FLUIDS
CARBOXYLIC ACIDS
CONNECTIVE TISSUE CELLS
FEMALE GENITALS
GLOBIN
GONADS
HEMATOPOIETIC SYSTEM
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INTAKE
LEUKOCYTES
LYMPHATIC SYSTEM
MALE GENITALS
MAMMALS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
POLLUTION
PORPHYRINS
PROTEINS
RODENTS
SOMATIC CELLS
TISSUES
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)