Methods: This experimental study included 30 male albino Wistar rats (260 to 320 g, 6 to 8 months old). Rats were randomly divided into three groups of 10. In group 1, 2 mL/kg intrapleural autologous blood was administered. In group 2, 2 mL/kg intrapleural ozoned autologous blood (1 mL/kg of autologous blood and 1 mL/kg of ozone mixture) was administered. In group 3, 2 mL/kg intrapleural saline was administered. Pleural surfaces were graded via macroscopic and microscopic examination on the 30^th day.

Results: Macroscopically, pleurodesis creating mild adhesion developed in group 1. General adhesion was seen in pleural space in group 2. No adhesion developed in group 3. Microscopically, ozoned blood caused moderate fibrosis and inflammatory response on visceral pleural surface (p<0.05). No significant change was seen in pleural surface microscopically in groups 1 and 3.

Conclusion: In this study, we detected that ozone increases the pleurodesis efficacy of autologous blood in rats. However, further studies with human populations are required to validate our results.