Morphology and fatty acid composition of erythrocytes from monkeys exposed to ozone for one year.

Monkeys (Macaca radiata) were exposed to a low dose (0.64 ppm) of ozone (O3) for 8 hr each day over a 1-year period. Control monkeys were exposed to filtered air. The morphology of the red blood cell (RBC) from these monkeys was analyzed by scanning electron microscopy. Red cells from control monkeys had normal morphology with 69% having biconcave shape (discocytes). In O3-exposed animals, blood contained only 35% discocytes. Knizocytes, stomatocytes, and spherocytes each have defined shape which are different from discocytes. The number of knizocytes and stomatocytes in O3-exposed monkeys was twice that of controls. In addition, significant levels of spherocytes were observed while they were absent in the blood of controls. The fatty acid composition of RBC from control and O3-exposed monkeys was the same. These were similar to that of human RBC. However, earlier reports of monkey RBC fatty acid composition differ from our results. These differences are discussed. We conclude that low-dose O3 exposure changes the morphology, but not the fatty acid composition, of erythrocytes in vivo.