Mice exposed in utero to 20 ppm benzene exhibit altered numbers of recognizable hematopoietic cells up to seven weeks after exposure.
Fundam Appl Toxicol 1988 Feb; 10(2):224-232
The effects of in-vitro exposure to benzene (71432) on the hematopoietic system were studied in mice. Pregnant Swiss-Webster- mice were exposed to 0, 5, 10, or 20 parts per million (ppm) benzene vapor from day six through day 16 of gestation. The dams were observed for clinical signs of toxicity. Selected dams were killed after exposure on day 16 and the number of live, dead, and resorbed fetuses was recorded. Selected fetuses were examined for malformations. Peripheral samples of fetal blood were collected and assayed for hemoglobin and numbers of red and white blood cells. The livers were removed and assayed for erythrocyte precursor cells. The other dams were allowed to deliver and 2 day and 6 week old offspring were taken and processed as before. Additionally spleens and femurs were removed from the 6 week old pups and assayed for recognizable cells in the hematopoietic differentiating, proliferating pool. No signs of maternal or fetal or neonatal nonhematopoietic toxicity were seen. No hematopoietic changes attributable to benzene were seen in the fetuses. Two day old neonates exposed to benzene showed reduced numbers of circulating erythrocyte precursors. The number of hepatic hematopoietic blast cells and granulocytic precursor cells was increased. Six week old mice exposed to benzene showed increased numbers of splenic hematopoietic blast cells and granulocytic precursor cells with a concomitant decrease in marrow erythrocyte precursor cells. The authors conclude that exposing pregnant mice to 20ppm benzene vapor induces hematotoxic responses in the offspring as manifested by alterations in the numbers of precursor cell types that persist for 7 weeks after exposure.
NIOSH-Publication; NIOSH-Grant; In-vivo-studies; Laboratory-animals; Organic-solvents; Aromatic-hydrocarbons; Transplacental-exposure; Blood-cells; Bone-marrow; Hematopoiesis
Fundamental and Applied Toxicology
Environmental Medicine N Y University Medical Center 550 First Avenue New York, N Y 10016