Effects of ozone preconditioning on recovery of rat colon anastomosis after preoperative radiotherapy.

BACKGROUND: Anastomotic leakage is a devastating complication of colorectal surgery. Neoadjuvant radiotherapy for colorectal cancer can affect the mechanical and biochemical parameters of anastomotic healing. It has been reported that ozone increases antioxidant enzyme activity and stimulates adaptive processes to oppose the pathophysiologic conditions mediated by reactive oxygen species (ROS). OBJECTIVES: The objective of this study was to investigate the effect of controlled administration of ozone on the healing of anastomosis and the activation of antioxidant enzymes in the colon after radiotherapy. MATERIAL AND METHODS: Rats (n = 48) were randomly assigned to the following groups: control groups (1 and 2), saline-treated and irradiated (IR) groups (3 and 4) and ozone oxidative preconditioning (OOP) and IR groups (5 and 6). Rats were exposed to whole-body IR (6 Gy) after pretreatment with either saline or ozone. Rats in groups 1, 3 and 5 were euthanized on postoperative day 3, whereas those in groups 2, 4 and 6 were euthanized on postoperative day 7. The anastomoses were performed on day 7 post-IR. The anastomotic segment was resected to measure hydroxyproline (HPO) content, myeloperoxidase (MPO) activity and malondialdehyde (MDA) concentration and for histopathological evaluation. RESULTS: The mean bursting pressure of the groups that underwent radiotherapy was lower than that of the control groups (p < 0.001). In groups 5 and 6, the tissue HPO concentrations were higher than those in groups 3 and 4. Although mean values for MPO activity in groups 5 and 6 were higher than those in groups 3 and 4, the differences were not significant. Regarding oxidative damage markers, MDA concentrations were significantly lower in group 5 than those in group 3. CONCLUSIONS: In this experimental model, OOP exerted favorable effects on colon anastomotic healing after radiation exposure.

Ozone protects the rat lung from ischemia-reperfusion injury by attenuating NLRP3-mediated inflammation, enhancing Nrf2 antioxidant activity and inhibiting apoptosis.

Ischemia-reperfusion injury (IRI) is a major cause of lung dysfunction during cardiovascular surgery, heart transplantation and cardiopulmonary bypass procedures, and the inflammatory response, oxidative stress, and apoptosis play key and allegedly maladaptive roles in its pathogenesis. The aim of this study was to initially elucidate whether ozone induces oxidative preconditioning by activating nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and secondly to determine whether ozone oxidative preconditioning (OzoneOP) protects the lung from IRI by attenuating nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3)-mediated inflammation, enhancing the antioxidant activity of Nrf2 and inhibiting apoptosis. Rats treated with or without OzoneOP (2 ml containing 100 µg/kg/day) were subjected to 1 h of lung ischemia followed by 2 h of reperfusion for 10 days. Lung damage, antioxidant capacity, inflammation and apoptosis were evaluated and compared among different groups after reperfusion. OzoneOP significantly ameliorated changes in lung morphology and protected the lung from IRI by attenuating oxidative stress, inflammation-induced injury and lung apoptosis. Moreover, OzoneOP increased the expression of Nrf2 and decreased the levels of NLRP3, apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), un-cleavable cysteine-requiring aspartate protease-1 (procaspase-1), cysteine-requiring aspartate protease-1 (caspase-1) and interleukin-1ß (IL-1ß) in the rat lungs. In summary, these results provide new insights into the molecular events modulated by ozone and suggest that ozone therapy may be an integrative support for patients with lung IRI.

Ozone protects rat heart against ischemia-reperfusion injury: A role for oxidative preconditioning in attenuating mitochondrial injury.

Ischemia-reperfusion injury (IRI) is a major cause of cardiac dysfunction during cardiovascular surgery, heart transplantation and cardiopulmonary bypass procedures. The purpose of the present study was to explore, firstly, whether ozone induces oxidative preconditioning by activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and, secondly, whether ozone oxidative preconditioning (OzoneOP) can protect the heart against IRI by attenuating mitochondrial damage. Rats were subjected to 30min of cardiac ischemia followed by 2h of reperfusion, with or without prior OzoneOP (100µg/kg/day) for 5 days. Antioxidant capacity, myocardial apoptosis and mitochondrial damage were evaluated and compared at the end of reperfusion. OzoneOP was found to increase antioxidant capacity and to protect the myocardium against IRI by attenuating mitochondrial damage and myocardial apoptosis. The study suggests a potential role for OzoneOP in protecting the heart against IRI during cardiovascular surgery, cardiopulmonary bypass procedures or transplantation.

Ozone oxidative intervention protects against hepatic ischemia reperfusion injury in rats / 中华肝胆外科杂志

Objective To explore the protective effect of ozone oxidative preconditioning on hepatic ischemia reperfusion injury in rats.Methods Eighteen 8-week-old SPF Sprague-Dawley male rats weighting 250 ～300 g were randomly divided into three groups (n =6 each):sham operation group (group S),ischemia/reperfusion group (group I/R) and ozone oxidative preconditioning group (group O3 + I/R).In Group O3 + I/R,rats received five-day preconditioning treatments by intraperitoneal injection of ozone and oxygen mixed gases (ozone concentration 50 mg/L,1 mg · kg-1 · d-1),and then experienced the procedure of hepatic ischemia/reperfusion injury.Model of hepatic ischemia/reperfusion injury was established by clamping the branches of hepatic artery and portal vein in the median and left lateral hepatic lobes for 45 min,followed by 3-h reperfusion.After reperfusion,blood samples were taken from the aorta abdominalis for detecting serum aminotransferases (ALT & AST).These rats were executed and the hepatic tissue samples were collected for measuring hepatic malondialdehyde (MDA) and superoxide dismutase (SOD) level.Results Compared with group S,concentrations of serum ALT,AST and hepatic MDA were increased in group I/R and O3 + I/R;concentrations of hepatic SOD were decreased (P ＜ 0.05) in group I/R,but concentration of hepatic SOD was increased in group O3 + I/R.Compared with group IR,concentrations of serum ALT,AST and hepatic MDA were decreased,while concentration of hepatic SOD was increased in group O3 + I/R (P ＜ 0.05).Conclusion Ozone oxidative preconditioning could inhibit the lipid peroxidation to protect the rats against hepatic ischemia/reperfusion injury.

Beneficial effects of nontoxic ozone on H2O2-induced stress and inflammation.

In this study, the anti-oxidant and anti-inflammatory efficacy of ozone oxidative preconditioning (OOP) were investigated on hydrogen peroxide (H2O2)-induced human lung alveolar cells. In MTT and trypan blue viability tests, while 100 µmol/L H2O2 caused a 17.3% and 21.9% decrease in the number of living cells, respectively, ozone at 20 µmol/L regenerated cell proliferation and prevented 9.6% and 11.0% of cell loss, respectively. In addition, H2O2 decreased the transcription levels of catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) 5.43-, 2.89-, and 5.33-fold, respectively, while it increased Bax, NF-κß, TNF-α, and iNOS expression 1.57-, 1.32-, 1.40-, and 1.41-fold, respectively. Ozone pretreatment, however, increased CAT, GPx, and SOD transcription levels 7.08-, 5.17-, and 6.49-fold and decreased Bax, NF-κß, TNF-α, and iNOS transcriptions by 1.25-, 0.76-, 3.63-, and 7.91-fold, respectively. Moreover, intracellular glutathione (GSH) level and SOD activity were decreased by 46.2% and 45.0% in the H2O2 treatment group, and OOP recovered 58.5% and 20.1% of the decreases caused by H2O2. H2O2 also increased nitrite levels 7.84-fold, and OOP reduced this increase by half. Consequently, OOP demonstrated potent anti-oxidant and anti-inflammatory effects on in vitro model of oxidative stress-induced lung injury.

Ozone preconditioning attenuates contrast-induced nephropathy in rats.

BACKGROUND: Contrast-induced nephropathy (CIN) is an important complication of vascular interventions. Ozone therapy can induce tolerance to ischemic insults, a phenomenon known as ozone oxidative preconditioning (OOP). The aim of this study was to investigate the effects of OOP on CIN. MATERIALS AND METHODS: Thirty-two Wistar rats were randomized into four groups (n = 8). The control group had intravenous saline injection. The contrast media (CM) group had intravenous meglumine/sodium diatrizoate injection to form CIN. The ozone (O3) group received intraperitoneal ozone for 5 d before the induction of CIN. The oxygen (O2) group was given an equal amount of oxygen for 5 d before the induction of CIN. The animals were sacrificed 48 h after the administration of contrast agent or saline. Kidneys were harvested, and blood samples were obtained. Renal function tests, serum and renal tissue malondialdehyde (MDA), and nitric oxide (NO) levels and renal oxidant system parameters were determined. Histologic examination was performed for renal injury. RESULTS: Serum blood urea nitrogen (BUN), creatinine, and serum and renal MDA were increased after contrast exposure. Renal NO was decreased, and there was prominent tubular necrosis in the CM group. Serum BUN, creatinine, serum and renal MDA, and grade of tubular necrosis were decreased in the O3 group as compared with those in the CM group. The levels of serum and renal NO and renal total antioxidant system in O3 group were higher than the levels in the CM group. CONCLUSIONS: OOP attenuates experimental CIN. This effect is suggested to be mediated by reinforcement of renal antioxidant defenses and maintenance of renal NO levels.

Ozone oxidative preconditioning inhibits renal fibrosis induced by ischemia and reperfusion injury in rats.

Ischemia and reperfusion injury (IRI) is a crucial contributor to the development of renal fibrosis. Ozone has been proposed as a novel medical therapy for various conditions, including organ IRI. The aim of this study was to investigate whether ozone oxidative preconditioning (OzoneOP) has a beneficial effect in preventing the development of renal fibrosis following IRI. Sprague Dawley rats were subjected to 45 min of ischemia followed by 8 weeks of reperfusion. Prior to surgery, rats in the OzoneOP group were treated with ozone and those in the IRI and Sham groups were untreated. Blood samples were collected for the detection of blood urea nitrogen (BUN) and creatinine (Cr) levels. To assess tissue fibrosis, Masson's trichrome staining was performed. Immunohistochemistry was also performed to determine the localization of α-smooth muscle actin (α-SMA). Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to analyze the expression of transforming growth factor (TGF)-ß1, α-SMA and Smad7. The levels of BUN and Cr did not significantly differ between groups. Rats pretreated with ozone showed markedly less interstitial fibrosis than untreated rats following IRI. In addition, immunohistochemistry revealed that α-SMA expression was attenuated in the OzoneOP group compared with the IRI group. RT-qPCR and western blot analysis showed that OzoneOP inhibited the IRI-induced increases in α-SMA and TGF-ß1 expression levels, and that the IRI-induced reduction in the expression of Smad7 was inhibited in the OzoneOP group. The results indicate that OzoneOP has beneficial effects on ischemic renal fibrosis. OzoneOP may exert its protective effects by a mechanism involving modulation of the TGF-ß1/Smad7 pathway.

The protective effect of ozone oxidative preconditioning against hypoxia/reoxygenation injury in rat kidney cells.

Abstract Ozone (O3) has been viewed as a novel treatment for different diseases in these years and oxidative stress and apoptosis play a key role in the pathogenesis of kidney diseases including renal ischemia and reperfusion (I/R). In the present study, we investigated the role of ozone oxidative preconditioning (OzoneOP) in attenuating oxidative stress and apoptosis in a hypoxia/reoxygenation (H/R) injury model using rat kidney cells. We induced H/R injury in kidney cells treated with or without OzoneOP. Oxidative stress parameters such as superoxide dismutase (SOD), malondialdehyde (MDA) and lactate dehydrogenase (LDH) were determined, as well as some apoptotic proteins. We observed that oxidative stress and apoptosis were increased in H/R group compared to OzoneOP group; however, these changes were significantly decreased by the treatment with OzoneOP. We concluded that OzoneOP can protect the kidney cells against H/R injury and its mechanism may be through the reduction of oxidative stress and apoptosis.

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.