Benzene and xylene are used by the chemical industry as raw materials
for the manufacturing of paints, insecticides, gums, resins and other
compounds. Through its myelotoxic actions, benzene produces hematologi
c changes ranging from pancytopenia to total bone marrow aplasia. The
present investigation Studied the possible effects of xylene on rat pe
ripheral blood and compared these effects to those produced by benzene
. Thirty-six male Wistar rats were injected sc with 2 mi benzene, xyle
ne or saline/kg body weight 3 times a week at 2-3 d intervals for 5 w.
The animals were lightly anesthetized and blood was collected by punc
ture af the retro-orbital plexus before the first administration of th
e solvents on d 7, 14, 21 and 35 of dosing, and 14 d after dosing was
discontinued. Xylene induced leukocytosis as an increase in absolute n
eutrophil numbers, whereas benzene caused leukocytopenia due to decrea
ses in absolute lymphocyte number. The 2 solvents reduced erythrocyte
counts, hematocrit and hemoglobin. Platelet counts were high throughou
t the dosing with benzene,and xylene. Fourteen d after discontinuation
of xylene dosing, the rats recovered their initial hematologic values
, whereas the animals dosed with benzene did not fully recover leukocy
tes and erythrocytes. The intoxications with benzene and xylene were n
ot solely hematologic since there was also growth retardation, as show
n by reduced weight gain, which did not recover after dosing ceased.