Propofol reduces nitric oxide-induced apoptosis in testicular ischemia-reperfusion injury by downregulating the expression of inducible nitric oxide synthase

Pathophysiology and management of testicular ischemia/reperfusion injury: Lessons from animal models

Testicular torsion is a urological emergency that involves the twisting of the spermatic cord along its course. Compelling pieces of evidence have implicated oxidative stress-sensitive signaling in pathogenesis of testicular I/R injury. Although, surgical detorsion is the mainstay management; blockade of the pathways involved in the pathogenesis may improve the surgical outcome. Experimental studies using various testicular I/R models have been reported in a bid to explore the mechanisms associated with testicular I/R and evaluate the benefits of potential therapeutic measures; however, most are limited by their shortcomings. Thus, this review was intended to describe the details of the available testicular I/R models as well as their merits and drawbacks, the pathophysiological basis and consequences of testicular I/R, and the pharmacological agents that have being proposed to confer testicular benefits against testicular I/R. This provides an understanding of the pathophysiological events and available models used in studying testicular I/R. In addition, this research provides evidence-based molecules with therapeutic potentials as well as their mechanisms of action in testicular I/R.

Serum nitric oxide levels are depleted in depressed patients treated with electroconvulsive therapy

BACKGROUND

Nitric oxide (NO) is an endogenous substance which has several endocrine functions and may act as neurotransmitter in the brain. High levels of NO may provoke nitrosative stress.

AIM

It was aimed to examine serum levels of NO in patients with depressive episodes who were treated with electroconvulsive therapy (ECT) in this study.

METHODS

The design was a case-control, follow-up study. Patients with depressive episodes (n = 23) and a healthy control group (n = 21) were enrolled. Three serum samples were obtained from the patient group (before ECT, after first and seventh sessions). NO, nitrite, and nitrate levels were examined.

STATISTICAL ANALYSIS

Differences between groups were examined with t-test or Mann-Whitney U-test. Longitudinal data were evaluated with Panel Regression Analysis and Kruskal-Wallis Test.

RESULTS

Serum levels of NO and nitrite decreased significantly after the seventh session of ECT administration compared to the baseline and first session. Nitrate levels did not differ between the assessments.

CONCLUSIONS

Reduction of the serum NO and nitrite levels might be a contributing factor for hypertension during the sessions. These findings are reflect the circulating NO levels. Further studies may dissect NO physiology in the brain in mental disorders and potential external effects.

Sodium nitrite-derived nitric oxide protects rat testes against ischemia/reperfusion injury

Testicular torsion, a common urologic emergency, is primarily caused by ischemia/reperfusion (I/R) injury of the testis. Nitric oxide (NO)-derived from nitrite (NO 2- ) has been reported to have prominent therapeutic effects on I/R injury in the heart, liver, and brain; however, its effects on testicular I/R injury have not been evaluated. This study, therefore, investigated whether NO from NO 2- is beneficial in a rat model of testicular I/R injury which eventually results in impaired spermatogenesis. Male Sprague-Dawley rats were assigned to the following seven groups: group A, sham-operated control group; Group B, I/R with no treatment; Groups C, D, and E, I/R followed by treatment with three different doses of NO 2- ; Group F, I/R followed by administration of NO 2- and NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt [C-PTIO]); and Group G, I/R followed by administration of nitrate (NO 3- ). NO 2- , NO 3- , and C-PTIO were intravenously administered. Histological examination of the testes and the western blot analysis of caspase-3 were performed. Levels of antioxidant enzymes and lipid peroxidation were measured. Germ cell apoptosis, oxidative stress, antioxidant enzymatic function, and lipid peroxidation in Group B were significantly higher than those in Group A. Group B exhibited an abnormal testicular morphology and impaired spermatogenesis. In contrast, testicular damages were attenuated in the NO 2- treatment groups, which were caused by reduction in superoxide and peroxynitrite levels and an inhibition of caspase-3-dependent apoptosis. The results of this study suggest NO 2- to be a promising therapeutic agent with anti-oxidant and anti-apoptotic properties in testicular I/R injury.

Propofol attenuates cytokine-mediated upregulation of expression of inducible nitric oxide synthase and apoptosis during regeneration post-partial hepatectomy

Purpose:

To determine the effects of propofol and ketamine anesthesia on liver regeneration in rats after partial hepatectomy (PHT).

Methods:

Male Wistar albino rats were assigned randomly to four groups of 10. Anesthesia was induced and maintained with propofol in groups 1 and 2, and with ketamine in groups 3 and 4. PHT was undertaken in groups 1 and 3. Rats in groups 2 and 4 (control groups) underwent an identical surgical procedure, but without PHT. At postoperative day-5, rats were killed. Regenerated liver was removed, weighed, and evaluated (by immunohistochemical means) for expression of inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS), apoptosis protease-activating factor (APAF)-1, and proliferating cell nuclear antigen (PCNA). Also, blood samples were collected for measurement of levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6.

Results:

Between groups 2 and 4, there were no differences in tissue levels of iNOS, eNOS, and APAF-1 or plasma levels of TNF-α and IL-6. eNOS expression was similar in group 1 and group 3. Expression of iNOS and APAF-1 was mild-to-moderate in group 1, but significantly higher in group 3. Groups 1 and 3 showed an increase in PCNA expression, but expression in both groups was comparable. Plasma levels of TNF-α and IL-6 increased to a lesser degree in group 1 than in group 3.

Conclusion:

Propofol, as an anesthetic agent, may attenuate cytokine-mediated upregulation of iNOS expression and apoptosis in an animal model of liver regeneration after partial hepatectomy.

Does intraperitoneal injection of propofol prior to detorsion improve testes weight and histopathological findings in a rat model?

Objectives

To determine the long-term preventive effects of intraperitoneal propofol on testicular ischemia–reperfusion injury in a rat model.

Materials and methods

Forty adult male albino Wistar rats were divided randomly into the following four groups according to the planned treatment (n=10 per group): group I, control; group II, sham-operated; group III, torsion/detorsion (T/D); and group IV, T/D plus propofol. Testicular ischemia was achieved by twisting the left testis 720° clockwise (ie, applying torsion) for 1 h. In the T/D plus propofol group (group IV), 50 mg/kg propofol was administered intraperitoneally 30 minutes before detorsion. Ipsilateral orchiectomy was performed under general anesthesia to determine the mean testicular weight and to enable histopathological examination of the testes using Johnsen’s mean testicular biopsy score 30 days after the surgical procedure in all groups.

Results

The testicular weights in groups I, II, III, and IV were 1.65±0.32, 1.59±0.33, 1.11±0.56, and 1.08±0.50 g (mean ± SD), respectively. Testicular weight was significantly lower in the T/D groups (III and IV) than in both the control and sham-operated groups (I and II), but there was no improvement in testicular weight as a result of propofol administration. Similarly, Johnsen’s mean testicular biopsy score was lower in groups III and IV than in groups I and II, but no positive effect was conferred by the administration of propofol in group IV.

Conclusion

The use of propofol in the treatment of testicular ischemia–reperfusion injury caused by testis torsion has no significant long-term therapeutic potential.

Mechanisms of testicular torsion and potential protective agents

Testicular torsion is a urological emergency most commonly seen in adolescence, involving a decrease in blood flow in the testis resulting from torsion of the spermatic cord that can result in gonad injury or even loss if not treated in time. Testicular ischaemia-reperfusion injury represents the principle pathophysiology of testicular torsion, with ischaemia caused by twisting of the spermatic cord, and reperfusion on its subsequent release. Many cellular and molecular mechanisms are involved in ischaemia-reperfusion injury following testicular torsion. Studies have investigated the use of pharmacological agents as supportive therapy to surgical repair in order to prevent the adverse effects of testicular torsion. Numerous substances have been proposed as important in the prevention of post-ischaemia-reperfusion testicular injury. A range of chemicals and drugs has been successfully tested in animal models for the purpose of mitigating the dangerous effects of ischaemia-reperfusion in testis torsion.

Differential influence of propofol on different cell types in terms of the expression of various oxidative stress-related enzymes in an experimental endotoxemia model

OBJECTIVES

Both overproduction of nitric oxide and oxidative injury to the cardiovascular and pulmonary systems contribute to fatal pathophysiology during endotoxemia. We investigated the effect of propofol on oxidative stress-related enzymes in lung (L2), heart (H9C2) and macrophage (NR8383) cells during endotoxemia.

METHODS

Experimental endotoxemia was induced by co-culture of Escherichia coli lipopolysaccharide (15 μg/mL) in the abovementioned three types of cells that were under the effect of propofol (15 or 30 μM for 1 or 4 hours). Cellular expression of induced nitric oxide synthase (iNOS), superoxide dismutase (SOD) 1 and 2, and p47phox (representing NADPH oxidase) were determined by immunoblotting. The cellular oxidative burst activity was determined using a dihydroethidium method via flow cytometry to represent the level of reactive oxygen species. The in vivo endotoxemia model was also employed for comparison using a systemic injection of lipopolysaccharide (15 mg/kg) under propofol maintenance (15 or 30 mg/kg/h). The Student t test (two groups) was used for statistical evaluation among the means, and the Newman-Keuls test was used for analysis of variance in the statistical analysis.

RESULTS

In lung L2 cells, propofol significantly reduced the expression of iNOS, SOD1, SOD2, and p47phox under LPS-induced endotoxemia. However, in H9C2 cardiac cells and NR8383 macrophages, only the expression of iNOS was significantly suppressed, but not that of SOD1, SOD2, or p47phox. The level of reactive oxygen species was suppressed in all three kinds of cell. In in vivo animal tissue, except for the suppression of iNOS expression in lung and heart cells, propofol in lung cells produced only SOD1 suppression, but in rat heart the expression of both SOD1 and SOD2 was suppressed.

CONCLUSION

These results suggest that propofol may have a protective role for lung cells. This effect is associated with its suppression of oxidative-related enzymes, including iNOS, SOD1, SOD2, and p47phox. In cardiac myocytes and macrophages, propofol also provides an antioxidative effect, probably via its inhibition of iNOS. The overall effect of propofol in the organs may be a combination of its effects on various cells. In addition, a reduction in reactive oxygen species plays a major role in the beneficial effect of propofol on experimental endotoxemia.

Propofol effects on the morphology of rat testes subjected to testicular ischemia-reperfusion

PURPOSE

To evaluate the effects of propofol as an inhibitor of tissue injury in testicular ischemia-reperfusion in rats.

METHODS

30 Wistar rats were assigned to one of three groups of 10 animals: G1, testicular exposure alone; G2 and G3: testicular ischemia caused by left spermatic cord torsion of 720º. In G3, propofol was administered intraperitoneally at 20 mg/kg/h 45 minutes after spermatic cord torsion. In G2 and G3, spermatic cords were detorsioned after 60 min. In all three groups, testes were subsequently repositioned in the scrotum. After 90 days, bilateral orchiectomy was performed for histological examination.

RESULTS

No abnormalities in seminiferous tubules were found in G1. In G2, 86.6% of left testes exhibited abnormalities, in contrast with 67.8% for right testes. In G3, these proportions were 57.3% and 45.6%, respectively. A statistically significant difference was found between G2 and G3.

CONCLUSION

Propofol reduced the tissue damage in rat testes subjected to ischemia-reperfusion caused by spermatic cord torsion.

Beneficial effects of taurine and carnosine in experimental ischemia/reperfusion injury in testis

PURPOSE

Testicular torsion can be thought of as an ischemia/reperfusion (I/R) injury to the testis. This study aimed to investigate the effects of taurine (TAU) and carnosine (CAR), which are strong antioxidants, on experimental testicular I/R injury model.

METHODS

Male Wistar albino rats were divided into four groups with eight animals in each. A sham operation was performed in group 1. To create testicular I/R, the left testis was torsioned 720° for 2 h followed by 2 h of detorsion. Groups 2 (I/R), 3 (I/R + TAU) and 4 (I/R + CAR) received intraperitoneal saline, TAU (250 mg/kg) and CAR (250 mg/kg), respectively, 1 h before detorsion. Thiobarbituric acid reactive substances (TBARS), diene conjugate (DC), protein carbonyls (PC), nonprotein sulfhydryl (NPSH), and vitamin C levels were measured in testis tissues as well as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Histopathological evaluation was also performed.

RESULTS

TBARS, DC, and PC levels were significantly increased in I/R group. TAU and CAR did not alter TBARS levels, but decreased the elevated DC and PC levels. There were no changes in testicular NPSH levels, SOD, and GPx activities in all groups; however, vitamin C significantly decreased in I/R group. CAR treatment was found to increase vitamin C levels as compared to I/R group. Histopathologically, both I/R + TAU and I/R + CAR groups showed significant increase in testicular spermatogenesis in comparison to I/R group.

CONCLUSION

Our results indicate that TAU and CAR reduces oxidative stress and may have a protective role in testicular I/R injury.

Protective effects of propofol on endotoxemia-induced acute kidney injury in rats

1. Animal studies suggest that propofol protects against endotoxaemia-induced lung and kidney injury. Upregulation of aquaporin expression in lung tissue mediates these effects, but the mechanism of action in the kidney is unclear. The present study examined the protective effects of propofol on endotoxaemia-induced acute kidney injury in rats. 2. A rat model of endotoxaemia was established using lipopolysaccharide (LPS). We determined the effects of 10% propofol administration 1 h before, during and 1 h after LPS-induced endotoxaemia on expression of aquaporin (AQP)-2, tumour necrosis factor (TNF)-α, intercellular adhesion molecule (ICAM)-1, caspase 3, Bcl-2 and Bax using reverse transcription-polymerase chain reaction, western blotting and immunocytochemistry. Renal morphology, superstructure, apoptosis and function were also assessed. 3. Normal renal tubular structure was seen in the propofol pretreated group, but LPS treatment resulted in changes to renal tissue morphology. Propofol treatment improved renal function in LPS-treated rats. Pretreatment with propofol 1 h before LPS normalized urine and serum osmolality, serum creatinine and blood urea nitrogen to control levels. Lipopolysaccharide downregulated expression of AQP-2 and downregulated the expression of ICAM-1 and TNF-α. These effects were reversed by propofol treatment. Lipopolysaccharide reduced the Bcl2 : Bax ratio and induced renal cell apoptosis and these effects were reduced by propofol treatment. Overall, propofol pretreatment had greater effects than concurrent treatment or propofol administration after LPS induction of endotoxaemia. 4. In conclusion, propofol pretreatment protected renal function in a rat model of endotoxaemia. Further studies are necessary to confirm this effect in other experimental models and in humans.

Attenuating sevoflurane-induced cellular injury of human peripheral lymphocytes by propofol in a concentration-dependent manner

Sevoflurane, one of the most commonly used inhalation anesthetics, induces apoptosis and oxidative stress in lymphocytes. Propofol, an intravenous anesthetic, exhibits antiapoptotic and antioxidative activities. Therefore, the present study aimed to investigate whether propofol attenuates sevoflurane-induced cellular injury in human peripheral lymphocytes. Lymphocytes harvested from healthy volunteers were assigned to treatments with different concentrations of propofol, or 8% sevoflurane, or their combination. Propofol at concentrations of 5, 10 or 25 μg/mL had little effect, but 50 μg/mL propofol or 8% sevoflurane significantly reduced cell viability and mitochondrial membrane potential (ΔΦm), and increased cell apoptosis, activation of caspase-3 and the production of intracellular reactive oxygen species, compared with untreated cells. Five and ten μg/mL propofol attenuated the impact of sevoflurane on cell viability, apoptosis and ΔΦm, and 5, 10 and 25 μg/mL propofol inhibited the production of intracellular reactive oxygen species stimulated by sevoflurane. However, a combination of 50 μg/mL propofol and 8% sevoflurane led to more severe cellular injury than sevoflurane alone. The results suggest that propofol can attenuate sevoflurane-induced cellular injury of human peripheral lymphocytes in a concentration-dependent manner, providing a rational for the clinical use of sevoflurane combined with appropriate doses of propofol.

Simvastatin induces the expression of hemeoxygenase-1 against ischemia-reperfusion injury on the testes in rats

We evaluate the protective role of simvastatin-induced HO-1 in remote preconditioning against testis ischemia-reperfusion (IR) injury in vivo. Simvastatin was intraperitoneally (i.p.) injected 24 h before IR injury. Testis was occluded in the right testis for 40 min and followed by 30 min of reperfusion to induce IR injury. Tin protoporphyrin (Snpp), a competitive inhibitor of hemeoxygenase, was i.p. injected 1 h before the IR injury in separate groups of rats. The rat testes were harvested 24 h later. Induction of HO-1 expression by simvastatin was significantly increased at 24 and 48 h. Rats pre-treated with simvastatin showed higher expression of HO-1 protein by Western blotting and immunohistochemistry (IHC), and presented lower caspases-3 activity by caspase-3 activity assay. TUNEL staining analysis revealed simvastatin pretreatment significantly reduced IR induced cellular apoptosis. Contrarily, the simvastatin-induced cytoprotective effect was entirely abolished by administrations of Snpp. Further, lower caspase-3 activities were also noted in simvastatin plus Snpp (SS) group than the control plus Snpp (CS) group. After IR injury, eNOS immunoreactivity was markedly increased in the germ cell and Leydig cell of testicular tissues. Pretreatment of simvastatin significantly decreased eNOS immunoreactivity in the germ cell of the tubules in the rat testes. In conclusion, we suggest HO-1 plays a protective role in IR-induced injury in the testes of rats.

Thiopental improves renal ischemia-reperfusion injury

Ischemia/reperfusion (I/R) occurs in a number of pathological conditions, including myocardial infarction, stroke, aortic surgery, cardiopulmonary bypass surgery, organ transplantation, resuscitation, and critical care. Massive and abrupt release of oxygen-free radicals after reperfusion triggers oxidative damage. Before critical operations or after resuscitation, it would be wise to find a suitable prophylactic treatment to avoid I/R damage. We aimed to determine whether several commonly used intravenous anesthetics protect against renal I/R injury.

METHODS

Animals were randomly divided into seven groups, each consisting of six animals: sham group, control group, thiopental group, propofol group, intralipid group, etomidate group, and ketamine group. At the end of the 60-min ischemic period, 60 min reperfusion was established and the materials administered 15 min before the reperfusion. At the end of the reperfusion period, the samples of blood and tissue were reaped for biochemical and serological evaluation.

RESULTS

I/R procedure significantly increased malondialdehyde (MDA) levels, decreased catalase (CAT) activities, and superoxide dismutase (SOD) levels. The lowest MDA mean level was in the thiopental group and the highest MDA mean level was in control group. The lowest CAT mean level was in the intralipid group and the highest CAT mean level was in the etomidate group. The lowest SOD mean level was in the control group and the highest SOD mean level was in the propofol group.

CONCLUSION

Thiopental and propofol, especially thiopental, are more effective to protect renal I/R injury.

Coenzyme Q10 treatment reduces lipid peroxidation, inducible and endothelial nitric oxide synthases, and germ cell-specific apoptosis in a rat model of testicular ischemia/reperfusion injury

In this experimental study, we assessed the preventive effects of coenzyme Q(10) (CoQ(10)) in a rat model of ischemia/reperfusion injury. The results of this study show that CoQ(10) administration before the reperfusion period of testicular torsion provides a significant decrease in testicular lipid peroxidation products and expressions of inducible nitric oxide synthase, endothelial nitric oxide synthase, and germ cell-specific apoptosis.

Differential protection against oxidative stress and nitric oxide overproduction in cardiovascular and pulmonary systems by propofol during endotoxemia

Background

Both overproduction of nitric oxide (NO) and oxidative injury of cardiovascular and pulmonary systems contribute to fatal cardiovascular depression during endotoxemia. We investigated in the present study the relative contribution of oxidative stress and NO to cardiovascular depression during different stages of endotoxemia, and delineated their roles in cardiovascular protective effects of a commonly used anesthetic propofol during endotoxemia.

Methods

Experimental endotoxemia was induced by systemic injection of E. coli lipopolysaccharide (LPS, 15 mg/kg) to Sprague-Dawley rats that were maintained under propofol (15 or 30 mg/kg/h, i.v.) anesthesia. Mean systemic arterial pressure (MSAP) and heart rate (HR) were monitored for 6 h after the endotoxin. Tissue level of NO was measured by chemical reduction-linked chemiluminescence and oxidative burst activity was determined using dihydroethidium method. Expression of NO synthase (NOS) was determined by immunoblotting. The Scheffé multiple range test was used for post hoc statistical analysis.

Results

Systemic injection of LPS (15 mg/kg) induced biphasic decreases in MSAP and HR. In the heart, lung and aorta, an abrupt increase in lipid peroxidation, our experimental index of oxidative tissue injury, was detected in early stage and sustained during late stage cardiovascular depression. LPS injection, on the other hand, induced a gradual increase in tissue nitrite and nitrate levels in the same organs that peaked during late stage endotoxemia. Propofol infusion (15 or 30 mg/kg/h, i.v.) significantly attenuated lipid peroxidation in the heart, lung and aorta during early and late stage endotoxemia. High dose (30 mg/kg/h, i.v.) propofol also reversed the LPS-induced inducible NO synthase (iNOS) upregulation and NO production in the aorta, alongside a significant amelioration of late stage cardiovascular depression and increase in survival time during endotoxemia.

Conclusion

Together these results suggest that oxidative injury and NO may play a differential role in LPS-induced cardiovascular depression. Oxidative tissue injury is associated with both early and late stage; whereas NO is engaged primarily in late stage cardiovascular depression. Moreover, propofol anesthesia may protect against fatal cardiovascular depression during endotoxemia by attenuating the late stage NO surge in the aorta, possibly via inhibition of iNOS upregulation by the endotoxin.