The impact of medical ozone on renal ischemic/reperfusion injury: A prospective randomized controlled study in dogs.

Abstract

This study evaluated the protective effects of ozone therapy in dogs with experimentally induced renal ischemia-reperfusion injury (IRI). Fifteen clinically healthy male mongrel dogs were randomly allocated into five groups. Group 1 served as the sham-operated control. Bilateral renal ischemia was induced in Group 2 (IRI control) and in three additional treatment groups receiving ozone therapy once daily via rectal insufflation. Group 3 received ozone preconditioning before IRI (PRE/IRI), Group 4 received ozone postconditioning after IRI (POST/IRI), and Group 5 received both interventions (PRE/IRI/POST). Venous blood samples were collected at baseline (D0) and at D1, D3, W1, W2, and W4 to measure serum malondialdehyde (MDA), glutathione peroxidase (GSH-px), blood urea nitrogen (BUN), and creatinine. Ultrasound-guided renal biopsies were obtained at D0, D3, W1, W2, and W4 for histopathology and immunohistochemistry. Serum creatinine and BUN progressively increased in the IRI group but were significantly reduced in all ozone-treated groups (P = 0.002). The PRE/IRI/POST group showed the greatest improvement, with the lowest values by W4. Ozone preconditioning also modulated early oxidative stress, preventing the initial rise in MDA and partially preserving GSH-px activity. Histopathological examination revealed marked acute tubular necrosis in the IRI group, whereas combined pre- and postconditioning produced the highest tubular regeneration scores. Immunohistochemistry supported reduced renal injury in the treated groups, with lower caspase-3 expression and higher HIF-1α activation, most notably in the combined therapy group. These findings suggest that ozone therapy is a safe and potentially effective strategy to mitigate renal IRI. Combined ozone preconditioning and postconditioning provided the greatest protection by reducing oxidative stress and apoptosis while promoting tubular regeneration and may represent a promising adjunctive approach in clinical settings such as kidney transplantation.