The effect of different ozone concentrations on white blood cell energy homeostasis

Abstract

Ozone therapy is an alternative form of therapy that has gained attention in the last couple of years. It is believed that O3 may exert a stimulatory effect on the antioxidant defence and immune systems and may therefore be effective in the treatment of ischemic disorders. diabetes mellitus. AIDS and other diseases. On the other hand. it is well known that O3 is a reactive molecule that is toxic to the pulmonary system. Therefore, there remains scepticism regarding its use as a form of therapy. In order to shed some light on this, the effects of ozone autohemotherapy (O3-AHT) on the energy homeostasis of white blood cells were investigated. The possible protective effects of the plasma antioxidant defence system during O3-AHT, were also investigated. Venous blood from six apparently healthy human donors was collected in heparin. In one aliquot a precise volume of blood was mixed with an equal volume of O2/O3 gas mixture containing 20 or 80 μg/ml O3 for 20 minutes. In the other aliquot, the plasma was washed out and the cells resuspended in a buffered phosphate solution. The buffered blood cells were treated with the same concentrations of O3. Control samples was either not treated or treated with a corresponding volume of O2 . Various biochemical analyses were done on the whole blood and buffered cells to determine the oxidant/antioxidant status, cell viability, apoptosis and mitochondrial function. The higher concentration of O3 increased oxidative stress and caused death of white blood cells. Antioxidant enzyme (catalase, glutathione reductase and glutathione peroxidase) activity and the plasma antioxidant capacity decreased, whereas superoxide dismutase levels increased slightly. Exposure to O3 also increased caspase 3/7 activity. A decrease in mitochondrial function was measured by a decrease in ATP levels and an increase in NADH/NAD+ ratio. Complex IV of the respiratory chain was almost completely inhibited by both O3 concentrations. These results indicated that the death of white blood cells was probably through apoptosis. These effects were more evident in the absence of plasma antioxidants. Therefore. high concentrations of O3 were damaging to the cells, but this effect was lessened by antioxidants present in plasma. In view of the results, the use of O3 as a therapy needs to be reconsidered.