Taurine protects against ischemia-reperfusion injury in rabbit livers

NMR-based metabonomics study on the effect of Gancao in the attenuation of toxicity in rats induced by Fuzi

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzi, the processed lateral root of Aconitum carmichaelii Debeaux, is a traditional Chinese medicine used for its analgesic, antipyretic, anti-rheumatoid arthritis and anti-inflammation effects; however, it is also well known for its toxicity. Gancao, the root of Glycyrrhiza uralensis Fisch., is often used concurrently with Fuzi to alleviate its toxicity. However, the mechanism of detoxication is still not well clear.

AIM OF THE STUDY

In this study, the effect of Gancao on the metabolic changes induced by Fuzi was investigated by NMR-based metabonomic approaches.

MATERIALS AND METHODS

Fifty male Wistar rats were randomly divided into five groups (group A: control, group B: Fuzi decoction alone, group C: Gancao decoction alone, group D: Fuzi decoction and Gancao decoction simultaneously, group E: Fuzi decoction 5h after Gancao decoction) and urine samples were collected for NMR-based metabolic profiling analysis. Statistical analyses such as unsupervised PCA, t-test, hierarchical cluster, and pathway analysis were used to detect the effects of Gancao on the metabolic changes induced by Fuzi.

RESULTS

The behavioral and biochemical characteristics showed that Fuzi exhibited toxic effects on treated rats (group B) and statistical analyses showed that their metabolic profiles were in contrast to those in groups A and C. However, when Fuzi was administered with Gancao, the metabolic profiles became similar to controls, whereby Gancao reduced the levels of trimethylamine N-oxide, betaine, dimethylglycine, valine, acetoacetate, citrate, fumarate, 2-ketoglutarate and hippurate, and regulated the concentrations of taurine and 3-hydroxybutyrate, resulting in a decrease in toxicity. Furthermore, important pathways that are known to be involved in the effect of Gancao on Fuzi, including phenylalanine, tyrosine and tryptophan biosynthesis, the synthesis and degradation of ketone bodies, and the TCA cycle, were altered in co-treated rats.

CONCLUSIONS

Gancao treatment mitigated the metabolic changes altered by Fuzi administration in rats, demonstrating that dosing with Gancao could reduce the toxicity of Fuzi at the metabolic level. Fuzi and Gancao administered simultaneously resulted in improved toxicity reduction than when Gancao was administrated 5h prior to Fuzi. In summary, co-administration of Gancao with Fuzi reduces toxicity at the metabolic level.

Nutraceutical strategies for ameliorating the toxic effects of alcohol

Rodent studies reveal that oxidative stress, much of it generated via induction/activation of NADPH oxidase, is a key mediator of a number of the pathogenic effects of chronic ethanol overconsumption. The highly reactive ethanol metabolite acetaldehyde is a key driver of this oxidative stress, and doubtless works in other ways to promote alcohol-induced pathology. Effective antioxidant measure may therefore be useful for mitigating the adverse health consequences of alcohol consumption; spirulina may have particular utility in this regard, as its chief phycochemical phycocyanobilin has recently been shown to function as an inhibitor of certain NADPH oxidase complexes, mimicking the physiological role of its chemical relatives biliverdin/bilirubin in this respect. Moreover, certain nutraceuticals, including taurine, pantethine, and lipoic acid, may have the potential to boost the activity of the mitochondrial isoform of aldehyde dehydrogenase, ALDH-2, accelerating conversion of acetaldehyde to acetate (which arguably has protective health effects). Little noticed clinical studies conducted nearly three decades ago reported that pre-ingestion of either taurine or pantethine could blunt the rise in blood acetaldehyde following ethanol consumption. Other evidence suggests that lipoic acid may function within mitochondria to maintain aldehyde dehydrogenase in a reduced active conformation; the impact of this agent on ethanol metabolism has however received little or no study. Studies evaluating the impact of nutracetical strategies on prevention of hangovers - which likely are mediated by acetaldehyde - may represent a quick, low-cost way to identify nutraceutical regimens that merit further attention for their potential impact on alcohol-induced pathology. Measures which boost or preserve ALDH-2 activity may also have important antioxidant potential, as this enzyme functions physiologically to protect cells from toxic aldehydes generated by oxidant stress.

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.

Effect of taurine on IRAK4 and NF-kappa B in Kupffer cells from rat liver grafts after ischemia-reperfusion injury

BACKGROUND

The aim of this study was to explore the protective mechanisms of taurine pretreatment against hepatic ischemia/reperfusion injury after liver transplantation.

METHODS

A Sprague-Dawley-to-Sprague-Dawley rat liver transplantation model was used in this study. At 0, 60, and 180 minutes after reperfusion, expression of interleukin-1 receptor-associated kinase-4 (IRAK-4) messenger ribonucleic acid and protein in Kupffer cells was determined by real-time polymerase chain reaction and Western blotting. The activity of nuclear factor κB in Kupffer cells was determined by electrophoretic mobility shift assay. The serum tumor necrosis factor-α level was detected by enzyme-linked immunosorbent assay. Serum transaminases, liver histology, and animal survival were also investigated.

RESULTS

At 60 and 180 minutes after reperfusion, levels of IRAK-4 messenger ribonucleic acid and protein, activities of nuclear factor κB, and levels of serum transaminases and tumor necrosis factor-α were all obviously elevated. However, changes in these parameters in rats treated with taurine were remarkably attenuated at the indicated time points.

CONCLUSIONS

These data suggest that taurine could protect against hepatic ischemia/reperfusion injury after liver transplantation, and the protective effects may be through downregulation of IRAK-4 and downstream nuclear factor κB and tumor necrosis factor-α expression in Kupffer cells.

Effect of methylene blue on the hemodynamic instability resulting from liver ischemia and reperfusion in rabbits

The experimental investigation was performed to study the effects of methylene blue (MB) on hemodynamic, biochemical, and tissue changes among rabbits undergoing liver ischemia and reperfusion (IR). Twenty-four rabbits were randomized into 5 groups: 1, SHAM, control; 2, MB infusion bolus (3 mg/kg); 3, IR, hepatic ischemia for 60 minutes followed by 120 minutes of reperfusion; 4, MB-R, undergoing ischemia that had received an MB bolus infusion (3 mg/kg) prior to reperfusion; 5, R-MB, undergoing ischemia and MB bolus infusion after hemodynamic instability caused by reperfusion. The analysis included continuous recording of vital signs. Blood samples were collected at 0, 60, and 180 minutes of IR to determine blood gases as well as biochemical markers of liver function, nitric oxide, lipid peroxidation, and neutrophil activity. At the end of each experiment, liver tissue samples were collected for histological evaluation of parenchymae markers. Statistical analysis used two-way analysis of variance (ANOVA) tests with significance set at P<.05. Vital signs significantly improved with MB infusion, irrespective of whether it was applied before or after reperfusion. Blood gas data revealed different patterns among the SHAM, MB, IR, MB-R, and R-MB groups, without statistical significance, except for favorable lactate results in the R-MB group (P<.01), which displayed greater survival. Biochemical tests did not show significant differences among the groups, whereas histological analysis revealed favorable appearances for the MB-R and R-MB groups. The MB effect lasted long after reperfusion, suggesting that improvement in the hemodynamic parameters was not based on liver integrity, but rather was possibly related to endothelial function.

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Matrine attenuates endotoxin-induced acute liver injury after hepatic ischemia/reperfusion in rats

PURPOSE

Hepatic ischemia/reperfusion (HIR) injury is an unavoidable consequence of major liver surgery, during which endotoxemia often takes place. This study aimed to investigate whether matrine has a protective effect against HIR-induced liver injury aggravated by endotoxin.

METHODS

Wistar rats were subjected to 30 min of HIR followed by lipopolysaccharide (LPS) (0.5 mg/kg) administration. At the indicated time points, six rats from each group (24 rats) were randomly euthanized to collect blood samples and livers.

RESULTS

Preadministration of matrine protected livers from injury induced by HIR+LPS as the histological score, myeloperoxidase activity and malondialdehyde contents, expression of macrophage-inflammatory protein-2, DNA-binding activity of nuclear factor κB, and serum levels of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase, tumor necrosis factor-α, soluble intercellular adhesion molecule-1, and nitric oxide were significantly reduced, and serum levels of interleukin-6 were further increased. HIR+LPS markedly induced cell apoptosis and necrosis, and upregulated the expression of cleaved caspase-3, Fas, and FasL. Matrine significantly reduced cell necrosis, but had a nonsignificant inhibitory effect on cell apoptosis and expression of cleaved caspase-3 and FasL.

CONCLUSIONS

Matrine attenuates endotoxin-induced acute liver injury after HIR mainly by its anti-inflammatory and antioxidative activities, and has little inhibitory effect on cell apoptosis.

Montelukast protects against testes ischemia/reperfusion injury in rats

INTRODUCTION

In this study, we investigate the effect of montelukast on histologic damage induced by testicular torsion-detorsion in rats.

METHODS

Twenty-one male Sprague-Dawley rats were separated into 3 groups, each containing 7 rats. A sham operation was performed in group 1 (control). In group 2 (ischemia-reperfusion [IR]/untreated), 1-hour detorsion of the testis was performed after 6 hours of unilateral testicular torsion. In group 3 (I-R/dextroamphetamine), after performing the same surgical procedures as in group 2, montelukast was given intraperitoneally. In all experimental rats, ipsilateral orchiectomies were performed for histological examination and tissue malondialdehyde (MDA), glutathione and myeloperoxidase assays.

RESULTS

Montelukast treatment significantly decreased the I-R-induced elevation in testes tissue MDA and glutathione levels were found to be preserved. The level of myeloperoxidase (MPO) activity was significantly increased in the testes tissue of the IR/untreated group. However, in I-R/montelukast treatment group significantly decreased testes tissue MPO level. Histopathologically, the in the group 2 rats, edema, congestion, hemorrhage between seminiferous tubules and necrosis of the germinal cells were predominant features in sections. However, most of the specimens in the montelukast treated group 3 showed grades-I and II injury. Additionally, the testicular injury score was lower in group 3 rats compared with group 2.

CONCLUSION

The current findings demonstrate that the montelukast decreased the severity of testicular injury by reversing the oxidative effects of testes I-R.

Protective effects of taurine against endotoxin-induced acute liver injury after hepatic ischemia reperfusion

Hepatic ischemia reperfusion (HIR) not only results in liver injury, but also leads to endotoxemia, which aggravates HIR-induced liver injury and dysfunction, or even causes liver failure. Taurine has been shown to protect organs from ischemia reperfusion or endotoxin by its anti-oxidant and anti-inflammatory activities. The aim of this study was to investigate whether taurine could attenuate endotoxin-induced acute liver injury after HIR. Wistar rats subjected to 30 min of hepatic ischemia followed by reperfusion and lipopolysaccharide (LPS) (0.5 mg/kg) administration, exhibited liver dysfunction (elevated serum levels of ALT, AST and LDH) and hepatic histopathological alteration. The serum levels of TNF-alpha and production of myeloperoxidase (MPO) and malondialdehyde (MDA) in liver tissues and apoptosis of hepatocytes were also increased after the combination of HIR and LPS. However, pre-administration of taurine protected livers from injury induced by the combination of HIR + LPS as the histological score, apoptotic index, MPO activity and production of MDA in liver tissues, and serum levels of AST, ALT, LDH and TNF-alpha, were significantly reduced. The expression of caspase-3, Fas and Fas ligand was upregulated in homogenates of livers from rats subjected to HIR and LPS, and this elevated expression could be inhibited by taurine. In summary, the results further emphasize the potential utilization of taurine in protecting livers against endotoxin-induced injury especially after HIR, by its anti-inflammatory, anti-oxidative and anti-apoptotic activities.

Taurine attenuates multiple organ injury induced by intestinal ischemia reperfusion in rats

BACKGROUND

Intestinal ischemia reperfusion (II/R) is a serious clinical condition associated with simultaneous multiple organ dysfunction. The purpose of this study was to investigate whether taurine, an anti-oxidative, anti-inflammatory, and anti-apoptotic agent, could attenuate multiple organ injury induced by II/R.

MATERIALS AND METHODS

Taurine was intravenously injected to Wistar rats 30 min before II/R; physiological saline and sham operation served as controls. II/R was produced by occlusion of superior mesenteric artery for 60 min. Rats were randomly sacrificed 1.5, 3, 12, and 36 h after II/R; blood samples were collected for assessing alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr), and tumor necrosis factor-alpha (TNF-alpha), and intestines, livers, kidneys, and lungs were removed for histological examination of scoring injury severity and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling analysis. The amount of lipid peroxides (LPO) was measured in intestinal tissues, and expression of caspase-3 was detected in all of the tissues with Western blot analysis.

RESULTS

II/R resulted in injury to intestines as well as livers, kidneys, and lungs, evidenced by morphological alteration, increased cell apoptosis, and elevated serum levels of ALT, AST, BUN, and Cr. The damage reached peak 3 h after II/R. The intestinal LPO and serum levels of TNF-alpha were increased after II/R. Pre-administration of taurine significantly attenuated multiple organ injury as the histological score, apoptosis index, LPO, and levels of ALT, AST, BUN, Cr, and TNF-alpha were significantly lower compared with saline controls.

CONCLUSIONS

Taurine attenuates multiple organ injury induced by II/R. Although the mechanism needs further investigation, taurine inhibits production of intestinal LPO, release of TNF-alpha, cell apoptosis, and expression of caspase-3.

Metabonomic study on the toxicity of Hei-Shun-Pian, the processed lateral root of Aconitum carmichaelii Debx. (Ranunculaceae)

The purpose of this paper was to study the effects of Hei-Shun-Pian, the processed lateral root of Aconitum carmichaelii Debx. (Ranunculaceae), on the metabolic profile of rats, to discuss the mechanism of toxicology and to find out the potential biomarkers of the toxic effects. Twenty male Wistar rats were divided into four groups (n=5) and each group were administered orally with the decoction of Hei-Shun-Pian (88.1g/kg per day, 35.6g/kg per day, 17.6g/kg per day) or equal volume of drinking water respectively for 14 days. Urine of every 24-h and the plasma of the last day were collected for NMR experiments, and then analyzed by multivariate analysis methods. Decreases in urinary excretion of taurine and trimethylamine-N-oxide (TMAO) and increases in urinary levels of citrate, 2-oxoglutarate (2-OG), succinate and hippurate were observed in the high and medium dosed groups at the early stage of the dosing period. Taurine level increased at the later stage of the dosing period to the normal value, and then even to a value higher than that of the control group at the end of the experiment. No metabolic differences were observed between low dosed and control groups until the later stage of the dosing period when a slight increase in urinary taurine level was observed, suggesting a cumulative effect. These results suggest the toxic effect of Hei-Shun-Pian on rat heart in a dose dependent manner.

Beneficial effect of taurine on testicular ischemia-reperfusion injury in rats

OBJECTIVES

To evaluate the effect of taurine, a potent antioxidant, on testicular ischemia-reperfusion injury due to excess reactive oxygen species produced by neutrophils after testicular torsion-detorsion.

METHODS

A total of 60 adult male Sprague-Dawley rats were randomly divided into three groups, each containing 20 rats. The control group underwent a sham operation of the left testis. In the torsion-detorsion group, the left testis was rotated 720 degrees counterclockwise for 2 hours. The treatment group underwent the same surgical procedure as the torsion-detorsion group, but taurine was administered intravenously at repair of the testicular torsion. One half of the rats in each group underwent orchiectomy 4 hours after detorsion for measurement of myeloperoxidase activity, an indicator of neutrophil accumulation in the testis, and for evaluation of tissue malondialdehyde, an indicator of intratesticular reactive oxygen species content. The remainder were killed at orchiectomy 3 months after detorsion for analysis of testicular spermatogenesis.

RESULTS

Unilateral testicular torsion-detorsion caused a significant increase in myeloperoxidase activity and the malondialdehyde level and a significant decrease in testicular spermatogenesis in the ipsilateral testes. The decrease in ipsilateral testicular spermatogenesis involved a reduction in testicular weight, mean seminiferous tubular diameter, number of germ cell layers, and mean testicular biopsy score. The rats treated with taurine had a significant decrease in myeloperoxidase activity and malondialdehyde level and a significant increase in testicular spermatogenesis in the ipsilateral testes compared with the torsion-detorsion group.

CONCLUSIONS

The results of our study have shown that the administration of taurine exerts a beneficial effect on testicular ischemia-reperfusion injury. This effect might be partly the result of a reduction in reactive oxygen species generation by diminishing neutrophil recruitment to the testis.