Does Ozone Change the Erythrocyte Function? Effects of oxidative stress on erythrocyte deformability and fragility. Serdar Caglayan, Rainer Bayer Heinrich Ehine University Department of Laser Medicine P.O. Box 101007 40001 Dusseldorf, Germany Abstract: Most methods established so far to estimate RBC deformability are hard to standardize and include high error of measurement. For our present investigation on the effects of oxygen (O2) and ozone (O3) on red blood cell (RBC) deformability we used the method of laser diffraction in combination of image analysis. Exposure to O2 neither altered RBC deformability nor induced hemolysis. After adding O3, hemolysis (up to 2.3 g% free hemoglobin) was observed, but deformability did not change. Using very high concentrations (>/- 160 ug/ml O3) deformability decreased in a concentration dependent manner. When the antioxidant catalase mechanism of the RBC was inhibited with azide (1 mM), O2 did not affect RBC deformability, but was considerably reduced by O3 as well as by hydrogen peroxide (H2O2). After exposing RBC to O2 and/or O3 mechanical fragility was investigated by filtration of the RBC suspensions (hematocrit 5%) through 3 um pore filter under pressure of 200 mmHg. Fragility remained unchanged after oxygenation. Astonishingly O3 in concentration >/- 7 ug/ml improved mechanical fragility (decrease of hemolysis after mechanical stress).