U. Plappert et al., EARLY EFFECTS OF BENZENE EXPOSURE IN MICE - HEMATOLOGICAL VERSUS GENOTOXIC EFFECTS, Archives of toxicology, 68(5), 1994, pp. 284-290
Female BDF1 mice were exposed to 100, 300 and 900 ppm benzene 6 h/day,
5 days/week, up to 8 weeks. Hematological studies included peripheral
blood data, T4 and T8 lymphocyte counts in the blood and the spleen,
hemopoietic stem and progenitor cell assays in the marrow (CFU-S, CFU-
C, BFU-E, CFU-E). The single cell gel assay (''comet assay'') was appl
ied in parallel with cells from the peripheral blood, bone marrow, spl
een and liver. The results showed minor changes in the stem and progen
itor cells and the development of a slight anemia at 4 and 8 weeks, in
agreement with reported data. New was the increase of the T4/T8 ratio
in the peripheral blood (not in the spleen) at the end of the first w
eek of exposure to 300 and 900 ppm. The results of the ''comet assay''
indicate a much higher sensitivity of this test system (strand breaks
and alkali labile sites of DNA). The tail moment indicative of the da
mage to DNA increased as early as 3 days with 300 ppm in the periphera
l blood cells. Furthermore, the liver cells did react to a much higher
extent than the other cells tested. With 100 ppm significant changes
were seen in the liver after 5 days, but not in the blood. The repair,
studied 24 and 48 h after the end of the exposure, was almost complet
e after 5-day exposure period in the blood and the liver, but not afte
r 4 weeks of exposure with 300 ppm in the blood, and 100 and 300 ppm i
n the liver.