Deformability and oxidant stress in red blood cells under the influence of halothane and isoflurane anesthesia

Energy drinks and alcohol in a binge drinking protocol in Wistar rats: Male and female behavioral and reproductive effects

The consumption of energy drinks is common among adolescents and young adults. The possible effects (mainly behavioral and reproductive) of ingestion in this population remain unknown. For this reason, this study aimed to evaluate the behavioral and reproductive effects of energy drinks and their main constituents (caffeine and taurine), as well as their combinations with alcohol, via a binge drinking protocol in male and female Wistar rats during puberty. In this study, 100 male and 100 female rats were treated with a binge drinking protocol 3 days a week over 4 weeks from postnatal day (PND) 28 to PND 60, which included 10 mL/kg by oral gavage of distilled water, energy drink, caffeine (3.2 mg/kg), taurine (40 mg/kg), and their combinations with alcohol (2 g/kg). The animals were evaluated by behavioral tests from PND 56 to PND 60 (open field, plus maze and object recognition) and reproductive parameters (estrous cycle regularity, weight of sexual organs, oocyte quality, spermatid and sperm count, sperm morphology and testosterone level). Locomotor activity was increased in females in the groups combined with alcohol (except alcohol + caffeine) and in the caffeine group. Long-term memory was increased in males in the caffeine and taurine groups even when combined with alcohol. The combination of energy drinks and alcohol did not have significant effects on the reproductive parameters of either sex of rats during puberty. We concluded that energy drinks (and their main constituents) and alcohol combinations did not cause alterations in reproductive profiles, and locomotor activity and long-term memory were increased in females and males, respectively.

Increased oxidative stress status in rat serum after five minutes treadmill exercise

Although it is accepted that an important correlation exists between the physical exercise and the oxidative stress status, the data regarding the levels of the main oxidative stress markers after physical training have been difficult to interpret and a subject of many controversies. There are also very few studies regarding the effects of short-time exercise on the oxidative stress status modifications. Thus, in the present report we were interested in studying the modifications of some oxidative stress markers (two antioxidant enzymes-superoxide dismutase and glutathione peroxidase, a lipid peroxidation parameter — malondyaldehide, the total antioxidant status and protein carbonyl levels), from the serum of rats that were subject to one bout of five minutes exercise on a treadmill, when compared to a control sedentary group. In this way, we observed a decrease of superoxide dismutase specific activity in the rats which performed the exercises. Still, no modifications of glutathione peroxidase specific activity were found between groups. In addition, increased levels of malondyaldehide and protein carbonyls were observed in the rats subjected to exercises. In conclusion, our data provides new evidence regarding the increase of the oxidative stress status, as a result of a 5-minutes bout of treadmill exercising in rats, expressed through a decrease in the SOD specific activity and the total antioxidant status and also an increase of the lipid peroxidation and protein oxidation processes.

Mechanism of Anesthetic Toxicity: Metabolism, Reactive Oxygen Species, Oxidative Stress, and Electron Transfer

There is much literature on the toxic effects of anesthetics. This paper deals with both the volatiles and locals. Adverse effects appear to be multifaceted, with the focus on radicals, oxidative stress (OS), and electron transfer (ET). ET functionalities involved are quinone, iminoquinone, conjugated iminium, and nitrone. The non-ET routes involving radicals and OS apparently pertain to haloalkanes and ethers. Beneficial effects of antioxidants, evidently countering OS, are reported. Knowledge at the molecular level should aid in devising strategies to combat the adverse effects.

Evaluation of antioxidant parameters in rats treated with sevoflurane

BACKGROUND AND OBJECTIVES

Sevoflurane is a halogenated fluorinated ether that undergoes hepatic biotransformation through cytochrome P4502E1. Halogenated ethers undergoing biotransformation by P4502E1 can produce reactive oxygen species (ROS), weakening the antioxidant defense mechanism. The objective of this study was to investigate the relationship between the activity of erythrocyte antioxidant enzymes and sevoflurane.

METHODS

Animals were divided in four groups: Group 1 - control: 100% oxygen (1 L.min(-1) for 60 min during five consecutive days); Group 2 - 4.0% sevoflurane in 100% oxygen (1 L.min(-1) for 60 minutes during five consecutive days); Group 3 - isoniazid (i.p.), 50 mg.kg(-1)/ day for four consecutive days, followed by 100% oxygen (1 L.min(-1) for 60 minutes during four consecutive days); Group 4 - intraperitoneal isoniazid, 50 mg.kg(-1) daily for four days, followed by 4.0% sevoflurane in 100% oxygen (1 L.min(-1) for 60 minutes during five days). Twelve hours after the last exposure to sevoflurane, animals were sacrificed and their blood was collected through the portal vein for analysis of antioxidant enzymes.

RESULTS

An increase in the activity of glucose-6-phosphate dehydrogenase and a decrease in the activity of catalase were observed, especially in the group of animals pre-treated with isoniazid. Changes in the activity of glutathione peroxidase were not observed.

CONCLUSIONS

The interaction between sevoflurane and cytochrome P450 2E1 with enzymatic inducers can lead to oxidative stress with prolonged and repetitive exposure.

In vivo Evaluation of the Effect of Zonisamide on the Hippocampal Redox State During Kainic Acid-Induced Seizure Status in Rats

The aim in this study is to observe the hippocampal redox state during kainic-acid (KA)-induced seizure status, and examine the effect of systemic preinjection of anticonvulsant zonisamide (ZNS) on the hippocampal redox. To perform under a freely moving state, in vivo microdialysis method was applied to electron paramagnetic resonance (EPR) spectroscopy. Half-life of 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCAM), a five-membered ring nitroxide radical, was used for the indicator of the hippocampal antioxidant ability. The changes in EPR signal intensities of PCAM decreased exponentially in all rats used. The average half-lives of PCAM was significantly shorter in the rats pretreated with ZNS than that of control group, and while the average half-lives of PCAM in the perfusate was significantly longer in the rats KA-induced status epilepticus than that of control (P < 0.01). Those of PCAM in the ZNS-pretreated rats followed by KA-injection were almost the same as those of control. These findings indicate that the pretreatment of ZNS increased the antioxidant ability in the hippocampus during KA-induced seizure. This study is the first in vivo evaluation of the antioxidant ability of ZNS as neuroprotective role against the free radicals performed under the condition of freely moving rats during seizure status.

Oxidative stress in pericardial fluid and plasma and its association with ventricular function

There are no studies evaluating oxidative stress markers both in pericardial fluid and plasma and whether they correlate with cardiac function indexes. The purpose of the study was to investigate whether oxidative stress markers in pericardial fluid and plasma are associated with left ventricular function.

METHODS AND RESULTS

Twenty-eight consecutive patients (class I or II NYHA) scheduled for myocardial revascularization, valve replacement, valve repair or closure of atrial septal defect. Plasma and pericardial fluid were collected and malondialdehyde, catalase, superoxide dismutase and glutathione peroxidase were determined. Left ventricular ejection fraction, left ventricular end diastolic diameter and left ventricular end systolic diameter were determined as echocardiographic indexes of ventricular function. We found that oxidative stress determined by a simple malondialdehyde (MDA) assay, correlated in plasma and pericardial fluid, and this parameter was associated with left ventricular end systolic diameter.

CONCLUSION

Plasma and pericardial fluid malondialdehyde levels can be used as an early marker of ventricular dysfunction.

Oxidative stress and mitochondrial glutathione in human lymphocytes exposed to clinically relevant anesthetic drug concentrations

STUDY OBJECTIVE

To evaluate the potential of compounds commonly used in anesthesia practice to affect the intracellular oxidant-antioxidant homeostasis of peripheral blood lymphocytes at clinically relevant concentrations; and to study the changes in reactive oxygen species production and measure the mitochondrial glutathione content.

DESIGN

Prospective, in vitro study.

SETTING

Experimental medical research laboratory at a University Hospital.

MEASUREMENTS

Lymphocytes were isolated from the peripheral blood of 15 healthy donors and incubated for 12 hours at 37 degrees C with the following drug concentrations: thiopental sodium 20 mmoL/mL, droperidol 130 micromol/mL, propofol 60 mmoL/mL, and succinylcholine 17 mmoL/mL. Reactive oxygen species (ROS) generation was determined by hydroethidine and 2',7'-dichlorofluorescein diacetate methods. Mitochondrial glutathione level was assessed using monobromobimane staining.

MEASUREMENTS AND MAIN RESULTS

Thiopental-treated lymphocytes exhibited an overgeneration of ROS, but no change was detected in mitochondrial glutathione quantity. Propofol and droperidol could not induce any perturbative effect on the oxidative state of T cells, whereas succinylcholine was found to markedly affect lymphocyte oxidative state both by impairing glutathione content and promoting exaggerated production of ROS.

CONCLUSION

Drugs commonly used in anesthesia practice may significantly alter the oxidative state of peripheral T cells. This mechanism could contribute to the immune suppression that occurs transiently in the early postoperative period.

Inhalation anesthetic-induced neuroinvasion by an attenuated strain of West Nile virus in mice

There are contradictory reports regarding the effects of inhalation anesthetics on the immune system. Measurable immune responses have been studied in vitro, but little is known about the in vivo effects in the intact organism. We used an attenuated, non-neuroinvasive, nonlethal strain of the encephalitic West Nile virus, termed WN-25, which can become lethal in combination with environmental stressors, to study possible modulatory immune effects of inhalation anesthetics in mice. Both single short-term exposure and repeated exposure to halothane and nitrous oxide were studied. Exposure to 30% CO2 served as a positive control. Mortality, brain invasion, spleen weight, and antiviral antibodies served as the experimental endpoints. Halothane and nitrous oxide led to viral brain invasion, increased mortality, and suppressed immune response in a concentration- and time-dependent manner. Repeated exposures had a cumulative effect. Assessment of the stability of the viral attenuation did not demonstrate any alteration in the character of the virus, suggesting an increased access to the brain by inhalation anesthetics that led to the fatal encephalitis. These findings may be of special concern to populations at risk, such as operating room staff and patients undergoing general anesthesia in endemic areas of encephalitic virus species, in which subclinical infection may develop into an overt disease.

Antioxidant protection of propofol and its recycling in erythrocyte membranes

alpha-Tocopherol is a potent antioxidant that effectively protects biological membranes against oxidative injury through coordination with ascorbic acid. Because propofol has a phenolic structure similar to that of alpha-tocopherol, this intravenous anesthetic may also have similar antioxidant activity. To test this hypothesis, the effect of propofol on oxidative injury of human erythrocytes was examined. Propofol inhibited oxidative hemolysis and cis-parinaric acid oxidation in erythrocyte membranes (ED(50) = 6 microM). Although ascorbic acid alone has no appreciable effect, the protective effect of propofol was enhanced by ascorbic acid. An electron spin resonance (ESR) study showed that propofol-derived radicals (g = 2.005) were continuously generated during the oxidation of erythrocyte membranes by an ascorbic acid-inhibitable mechanism. These and other results suggest that propofol interacts with ascorbic acid, thereby exhibiting potent antioxidant activity in and around membranes as does alpha-tocopherol. Kinetic analysis revealed that propofol increased the membrane fluidity of erythrocytes, thereby increasing their resistance to physical and hemodynamic stress. Further, a greater preservation of red blood cell counts was seen after surgery with propofol compared with conventional sevoflurane anesthesia. Thus, propofol may protect erythrocytes against both oxidative and physical stress, indicating its potential as an efficient and safe antioxidant.

Red blood cell trauma during cardiopulmonary bypass: narrow pore filterability versus free haemoglobin

Ten patients admitted for coronary artery bypass grafting were investigated with respect to the influence of cardiopulmonary bypass (CPB) on red blood cell (RBC) trauma. Blood samples were collected prior to, at the start of, and at 30 and 60 min of CPB. RBC deformability was assessed by filtering re-suspended RBCs through a polycarbonate membrane using a computer-controlled filtrometer. Multiple regression analysis was employed to evaluate RBC flow-curve characteristics denoted by the initial filtration rate (IFR) and clogging slope (CS). Release of free haemoglobin was determined concomitantly. IFR was estimated at 90.39 microl/s and CS at -5.32 microl/s2 prior to CPB. During 60 min of CPB, neither IFR nor CS deviated significantly (p > 0.05) from these reference values. However, release of free haemoglobin increased significantly (p < 0.018) from the start of CPB to the 60-min determination. In conclusion, 60 min of CPB seems not to alter significantly RBC deformability in a 5 microm pore filtration model, despite a significant release of haemoglobin.