Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats

Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage.

Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats.

Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage.

The efficiency of different chemoradiotherapy regimens in patients with paediatric nasopharynx cancer: review of 46 cases.

The purpose of this study was to evaluate the role of combined modality treatment in patients with paediatric nasopharynx cancer (NPC). Forty-six patients with paediatric NPC were retrospectively analysed. Forty-four of 46 patients received combined modality treatment. Five-year overall survival and progression-free survivals were 70% and 72% for the whole group, and only three of 46 patients had loco-regional relapse. Complete remission was obtained in 18 of 45 patients (40%), and the overall survival (94% vs. 62% and 19%, p = 0.0009) and disease-free survivals (93% vs. 70% and 16%, p = 0.0002) were significantly better in complete responders when compared with the patients who had partial response or stable disease. The 5-year overall survival and disease-free survivals of the patients who received neoadjuvant chemotherapy (CT) and radiotherapy (RT) followed by CT were superior to the other groups (77% and 80%, respectively). The number of total CT cycles (p = 0.0001), nodal stage (p = 0.05) and treatment response (p = 0.0009) were significant prognostic factors for overall survival. The treatment type (p = 0.02), the number of total CT cycles (p = 0.0006), nodal stage (p = 0.05) and treatment response (p = 0.0002) were found as significant prognostic factors for disease-free survival. The survival of patients receiving six or more CT cycles was also significantly better than that of patients receiving less than six cycles (p = 0.0001). In patients with locally advanced paediatric NPC, CT should be added to RT to improve outcome. However, a standard protocol is yet to be identified, and further studies evaluating the addition of interferon or immunotherapy to CT and RT shall be performed.