Jovana Bradic

Impact of hyperbaric oxygenation on oxidative stress in diabetic patients

Taking into consideration that a high concentration of oxygen can express toxic effects due to production of reactive oxygen species (ROS), the aim of our investigation was to establish the influence of hyperbaric oxygenation on oxidative stress parameters and antioxidant enzymes in patients with diabetes mellitus (DM) type 2. Investigation included 50 patients with DM type 2 divided into two groups. The first group consisted of 25 patients, mean age 70 years, mean duration of illness 12 years and without manifest peripheral vascular complications (Wagner 0). The second group consisted of 25 patients, mean age 74 years, mean duration of illness 17 years and with manifest peripheral vascular complications (Wagner 1-5). All patients underwent the same therapeutic protocol, which included 10 hyperbaric oxygenation therapies, once a day for a duration of 60 minutes, with an average partial oxygen pressure of 1.7 atmospheres absolute (ATA). In blood samples the following parameters of redox balance were determined: levels of nitrites (NO₂-), index of lipid peroxidation (TBARS), superoxide anion radical (O₂-), hydrogen peroxide (H₂O₂) and antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Our results clearly show that hyperbaric oxygen (HBO₂) therapy does not have a pro-oxidative effect. Additionally, it seems that this procedure strongly mobilized the antioxidant enzyme system, thus improving defense from oxidative damage. All significant data are marked as P ⟨0.05. Our results have shown that in terms of ROS production, HBO₂ can be safe to use in patients suffering from DM type 2 with or without vascular complications.

Effects of Ischemic and Proton Pump Inhibitors Preconditioning on Oxidative Stress of Isolated Rat Heart

Abstract Aim of present study was to determine the participation of various biomarkers of oxidative damage: nitrite (NO2−), superoxide anion radicals (O2−), index of lipid peroxidation (TBARS) and hydrogen peroxide (H2O2) in coronary circulation after application of the different models of preconditioning such as ischemic and preconditioning with proton pump inhibitors. Examining a biochemical markers of oxidative damage we did not notice any increased production values of any parameter, according to that we can hypothesize that possible occurrence of reperfusion injury after ischemia and PPIs preconditioning is not mediated by this mechanism. Due to the very difficult and controversial application of ischemic preconditioning in clinical practice, the results of this study suggest that in the future proton pump inhibitors can contribute to the prevention of myocardial damage following ischemia

The Effects of Potassium Cyanide on the Functional Recovery of Isolated Rat Hearts after Ischemia and Reperfusion: The Role of Oxidative Stress

This investigation is aimed at examining the effects of pharmacological PostC with potassium cyanide (KCN) on functional recovery, gene expression, cytochrome c expression, and redox status of isolated rat hearts. Rats were divided into the control and KCN groups. The hearts of male Wistar albino rats were retrogradely perfused according to the Langendorff technique at a constant perfusion pressure of 70 cmH2O. After stabilisation, control hearts were subjected to global ischemia (5 minutes), followed by reperfusion (5 minutes), while experimental hearts underwent global ischemia (5 minutes) followed by 5 minutes of reperfusion with 10 μmol/L KCN. The following parameters of heart function were measured: maximum and minimum rates of pressure development, systolic and diastolic left ventricular pressure, heart rate, and coronary flow. Levels of superoxide anion radical, hydrogen peroxide, nitrites, and index of lipid peroxidation (measured as thiobarbituric acid-reactive substances) were measured in coronary venous effluent, and activity of catalase was determined in heart tissue. Expression of Bax, Bcl-2, SOD-1, SOD-2, and cytochrome c was studied as well. It was shown that expression of Bax, Bcl-2, and SOD-2 genes did not significantly differ between groups, while expression of SOD-1 gene and cytochrome c was lower in the KCN group. Our results demonstrated that KCN improved the recovery of myocardial contractility and systolic and diastolic function, enhanced catalase activity, and diminished generation of prooxidants. However, all possible mechanisms and potential adverse effects of KCN should be further examined in the future.

Interleukin-6 as possible early marker of stress response after femoral fracture

Bone fracture healing is a complex process which at best results in full recovery of function and structure of injured bone tissue, but all the mechanisms involved in this process, and their mutual interaction, are not fully understood. Despite advancement of surgical procedures, this type of fractures is still a major public health concern. In the last few decades, a lot of attention is focused on the oxygen-free radicals and inflammatory response markers as important factors of skeletal injury. Thus, the aim of the present study was to follow the changes in redox balance and inflammatory response in elderly patients with femoral fractures during the earliest stages of fracture healing, by measuring the values of the observed markers immediately after fracture, as well as the first, third, and seventh postoperative day. Present study was performed on a group of 65 elderly patients with femoral neck fractures, recruited from the Orthopedic Clinic, Clinical Centre Kragujevac in the period from February to May 2015. Redox status was measured spectrophotometrically and evaluated by measuring the levels of index of lipid peroxidation (measured as TBARS), nitrite (NO2−), superoxide anion radical (O2−), and hydrogen peroxide (H2O2) in plasma, while activities of corresponding antioxidative enzymes, catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH) were measured in erythrocytes. The cytokine concentrations of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were determined in plasma, using ELISA assays specific for human cytokines. Our study showed that redox status and TNF-α in elderly patients with femoral fractures did not show statistically significant changes during the early phase of fracture healing. On the other hand, IL-6 increased statistically in first day after intervention. This preliminary study has shown our observations, and we hope that these results may help in better understanding mechanisms which are included at fracture healing. More importantly, this study attempted to create a platform for further research.

THE EFFECTS OF DICLOFENAC AND IBUPROFEN ON HEART FUNCTION AND OXIDATIVE STRESS MARKERS IN THE ISOLATED RAT HEART

ABSTRACT Eicosanoids lead to the promotion of inflammation, cause fever and pain and have many other eff ects. NSAIDs block the action of cyclooxygenase (COX) during the process of converting arachidonic acid into inflammatory mediators, thus reducing the symptoms of inflammation. Investigations focusing on nonselective COX inhibitors, used in high doses, revealed harmful eff ects on myocardial function. Th e aim of our study was to assess the eff ects of two nonselective NSAIDs, diclofenac and ibuprofen, on cardiodynamic parameters, coronary flow and oxidative stress biomarkers in isolated rat hearts. Th e hearts of male Wistar albino rats were excised and retrogradely perfused according to the Langendorff technique at gradually increased coronary perfusion pressures (40-120 cm H2O). Th e experiments were performed under controlled conditions (Krebs-Henseleit physiological solution). Th e hearts were perfused with 10 μmol/l diclofenac and 10 μmol/l ibuprofen. Th e heart function parameters, including the maximum rate of pressure development (dp/dt max), minimum rate of pressure development (dp/dt min), systolic left ventricular pressure (SLVP), diastolic left ventricular pressure (DLVP), mean perfusion pressure (MBP) and heart rate (HR), were continuously registered. Coronary flow (CF) was measured flowmetrically. Oxidative stress markers, including the index of lipid peroxidation measured as TBARS, nitric oxide measured through nitrites (NO2 -), superoxide anion radical (O2 -), and hydrogen peroxide (H2O2) in the coronary venous effluent, were assessed spectrophotometrically. Our results showed that diclofenac aff ected cardiodynamic parameters more significantly than did ibuprofen. Furthermore, the present data indicate that both estimated COX inhibitors do not promote the production of reactive oxygen species. SAŽETAK Eikosanoidi dovode do zapaljenja, uzrokuju groznicu i bol, i imaju mnoge druge efekte na organizam. NSAID onemogućavaju delovanje ciklooksigenaze (COX) u procesu konvertovanja arahidonske kiseline u medijatore zapaljenja, i na taj način smanjuju simptome zapaljenja. Istraživanja koja se bave primenom neselektivnih inhibitora COX, koji se koriste u visokim dozama, pokazala su njihove štetne efekte na funkciju miokarda. Cilj našeg istraživanja je bio da ispita efekte neselektivnih NSAID, diklofenaka i ibuprofena, na kardiodinamske parametre, koronarni protok i biomarkere oksidativnog stresa izolovanog srca pacova. Srca mužijaka Wistar albino pacova su uzimana i retrogradno perfundovana prema Langedorff -ovoj tehnici sa postepenim povećanjem perfuzionog pritiska (40-120 cm H2O). Eksperimenti su prvo izvođeni u kontrolnim uslovima (primena fiziološkog Krebs-Henseleit-ovog rastvora), nakon čega su srca perfundovana sa: 10 μmol/l dikolfenaka i 10 μmol/l ibuprofena. Parametri srčane funkcije koji su kontinuirano praćeni su: maksimalna stopa razvoja pritiska (dp/dt max), minimalna stopa razvoja pritiska (dp/dt min), sistolni pritisak u levoj komori (SLVP), dijastolni pritisak u levoj komori (DLVP), srednji perfuzioni pritisak (MBP) i frekvenca srčanog rada (HR). Koronarni protok (CF) je registrovan floumetrijski. Markeri oksidativnog stresa: indeks lipidne peroksidacije meren kao TBARS, azot-monoksid utvrđivan preko nitrata (NO2 -), superoksid anjon radikal (O2 -), i vodonik peroksid (H2O2) su mereni spektrofotometrijski u koronarnom venskom efluentu. Naši rezultati su pokazali da diklofenak ispoljava značajniji uticaj na kardiodinamske parametre u odnosu na ibuprofen. Pored toga, rezultati ove studije su pokazali da oba ispitivana inhibitora COX ne dovode po produkcije reaktivnih vrsta kiseonika.