Acute hematologic and hemorheologic effects of sulfur dioxide inhalation.

Fifty male rats were exposed to 0.87 ppm sulfur dioxide (SO2) for 24 hr. Hematologic and hemorheologic parameters measured in this group were compared with the results of a control group of 51 male rats. Hematocrit values were found to be higher (p less than .005) in the SO2-treated group (43.55 +/- 0.41%, mean +/- standard error), when compared to the control group value (41.97 +/- 0.35%). Sulfhemoglobin values were also higher (p less than .0001) in the SO2-treated group (0.60 +/- 0.08%) than the control group (0.08 +/- 0.02%). Osmotic hemolysis ratio was slightly increased (p less than .05) in the 0.55% sodium chloride solution. However, whole blood and packed cell viscosities were lower in the SO2-treated animals, while there was no significant difference in the plasma viscosities. The mechanism of these effects could not be clarified completely, but structural and functional effects of SO2 inhalation on peripheral erythrocytes were discussed.