How an ill-conceived methodological approach can condemn the medical use of ozone therapy

The ozone paradox: ozone is a strong oxidant as well as a medical drug

After five decades characterized by empiricism and several pitfalls, some of the basic mechanisms of action of ozone in pulmonary toxicology and in medicine have been clarified. The present knowledge allows to understand the prolonged inhalation of ozone can be very deleterious first for the lungs and successively for the whole organism. On the other hand, a small ozone dose well calibrated against the potent antioxidant capacity of blood can trigger several useful biochemical mechanisms and reactivate the antioxidant system. In detail, firstly ex vivo and second during the infusion of ozonated blood into the donor, the ozone therapy approach involves blood cells and the endothelium, which by transferring the ozone messengers to billions of cells will generate a therapeutic effect. Thus, in spite of a common prejudice, single ozone doses can be therapeutically used in selected human diseases without any toxicity or side effects. Moreover, the versatility and amplitude of beneficial effect of ozone applications have become evident in orthopedics, cutaneous, and mucosal infections as well as in dentistry.

A physicochemical investigation on the effects of ozone on blood

Ozonation of either human whole blood or saline-washed erythrocytes causes considerable damage to the latter and this result has opened a controversy. With the benefit of hindsight, it appears logical that once erythrocytes are deprived of the potent antioxidants of plasma, they become very sensitive to the oxidant effects of ozone. The aim of the present work was to perform a physical-chemical evaluation of some critical parameters able to clarify this issue. We have ascertained that when whole blood is exposed to the appropriate ozone doses used in human therapy, no damage ensues while saline-washed erythrocytes undergo conspicuous haemolysis. The dogma that ozone is always toxic is incorrect because its reactivity below the concentration of 80mug/mL can be controlled by the plasmatic antioxidant system.

A realistic evaluation of the action of ozone on whole human blood

We have clarified the role of the ozone concentration in relation to the resistance of human erythrocytes in whole human blood or in blood diluted either in saline or in distilled water. Spectrophotometric data related to haemoglobin were evaluated by exposing samples of fresh human blood directly to ozone doses (ratio 1:1 volume), within the therapeutic range (0.21-1.68 mM) and to one toxic dose (3.36 mM). Furthermore, the same determinations have been carried out after previous dilution of the same blood with either pure water or physiological saline (1 ml blood + 29 ml diluent) followed by ozonation with the above reported ozone doses. Addition of either saline or water implies a dilution of plasma antioxidants and also total haemolysis after water dilution. Particularly the latter case represents a most unphysiological situation because the osmotic shock causes the solubilization of the erythrocytic content. While it is possible to demonstrate that after haemolysis there is an ozone-concentration dependent transformation of some oxyhaemoglobin to methaemoglobin, no such process occurs after ozonation of whole blood. The results of this study fully confirm our previous data that judicious ozone doses neither damage erythrocytes, nor induce oxidation of intracellular haemoglobin. We hope that our conclusions will definitively clarify the absence of toxicity of ozonetherapy.