α-Lipoic acid and ebselen prevent ischemia/reperfusion injury in the rat intestine

Protective Effect of Ebselen on Ischemia-reperfusion Injury in Epigastric Skin Flaps in Rats

The purpose of this study was to determine the role of oxidized diacylglycerol (DAG) and the molecular mechanism underlying ischemia-reperfusion (I/R) injury in rat skin flaps. The protective effect of ebselen on the viability of rat skin flaps with I/R injury was investigated. Flaps were designed and raised in the left inguinal region. Then, a microvascular clamp was applied to the vascular pedicle and reperfused after 6 hr. After 7 days of I/R (I/R group), the skin flap survival area ratio was significantly reduced compared to the normal skin. The administration of ebselen significantly improved the ratio compared to the I/R group. The flap survival area ratio of the I/R + ebselen group was significantly improved compared to the I/R + vehicle group. In the I/R + ebselen group, the oxidized DAG content and intensity of phosphorylated PKCα and PKCδ were significantly lower compared to the I/R + vehicle group. Furthermore, the inflammatory response was suppressed in the I/R + ebselen group compared to the I/R + vehicle group. These results indicate that ebselen is useful as a preventive and therapeutic agent for skin flap necrosis caused by I/R, because of reduction and elimination of oxidized DAG.

Albendazole ameliorates inflammatory response in a rat model of acute mesenteric ischemia reperfusion injury

BACKGROUND

Acute mesenteric ischemia is known as a life threatening condition. Re-establishment of blood flow in this condition can lead to mesenteric ischemia reperfusion (MIR) injury which is accompanied by inflammatory response. Still, clear blueprint of inflammatory mechanism underlying MIR injury has not been provided. Interestingly, Albendazole has exhibited notable effects on inflammation and cytokine production. In this study, we aimed to evaluate outcomes of MIR injury following pretreatment with Albendazole with respect to assessment of mesenteric inflammation and ischemia threshold.

METHODS

Male rats were randomly divided into sham operated, vehicle treated, Albendazole 100 mg/kg and Albendazole 200 mg/kg groups. MIR injury was induced by occlusion of superior mesenteric artery for 30 min followed by 120 min of reperfusion. Samples were utilized for assessment of epithelial survival and villous height. Immunohistochemistry study revealed intestinal expression of TNF-α and HIF-1-α. Gene expression of NF-κB/TLR4/TNF-α/IL-6 was measured using RTPCR. Also protein levels of inflammatory cytokines in serum and intestine were assessed by ELISA method.

RESULTS

Histopathological study demonstrated that pretreatment with Albendazole could ameliorate decline in villous height and epithelial survival following MIR injury. Also, systemic inflammation was suppressed after administration of Albendazole. Analysis of possible participating inflammatory pathway could demonstrate that intestinal expression of NF-κB/TLR4/TNF-α/IL-6 is significantly attenuated in treated groups. Eventually, IHC study illustrated concordant decline in mesenteric expression of HIF-1-α/TNF-α.

CONCLUSION

Single dose pretreatment with Albendazole could ameliorate inflammatory response and enhance ischemia threshold following induction of MIR injury. More studies would clarify existing causality in this phenomenon.

Alpha-Lipoic Acid Promotes Intestinal Epithelial Injury Repair by Regulating MAPK Signaling Pathways

Intestinal epithelial cells are an essential barrier in human gastrointestinal tract, and healing of epithelial wound is a key process in many intestinal diseases. α-Lipoic acid (ALA) was shown to have antioxidative and anti-inflammatory effects, which could be helpful in intestinal epithelial injury repair. The effects of ALA in human colonic epithelial cells NCM460 and human colorectal adenocarcinoma cells Caco-2 were studied. ALA significantly promoted NCM460 and Caco-2 migration, increased mucosal tight junction factors ZO-1 and OCLN expression, and ALA accelerated cell injury repair of both cells in wound healing assay. Western blot analysis indicated that ALA inhibited a variety of mitogen-activated protein kinase (MAPK) signaling pathways in the epithelial cells. In conclusion, ALA was beneficial to repair of intestinal epithelial injury by regulating MAPK signaling pathways.

Therapeutic Implications of Caffeic Acid in Cancer and Neurological Diseases

Caffeic acid (CA) is found abundantly in fruits, vegetables, tea, coffee, oils, and more. CA and its derivatives have been used for many centuries due to their natural healing and medicinal properties. CA possesses various biological and pharmacological activities, including antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. The potential therapeutic effects of CA are mediated via repression and inhibition of transcription and growth factors. CA possesses potential anticancer and neuroprotective effects in human cell cultures and animal models. However, the biomolecular interactions and pathways of CA have been described highlighting the target binding proteins and signaling molecules. The current review focuses on CA’s chemical, physical, and pharmacological properties, including antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. We further described CA’s characteristics and therapeutic potential and its future directions.

Effects of Lipoic Acid on Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury often occurred in some pathologies and surgeries. I/R injury not only harmed to physiological functions of corresponding organ and tissue but also induced multiple tissue or organ dysfunctions (even these in distant locations). Although the reperfusion of blood attenuated I/R injury to a certain degree, the risk of secondary damages was difficult to be controlled and it even caused failures of these tissues and organs. Lipoic acid (LA), as an endogenous active substance and a functional agent in food, owns better safety and effects in our body (e.g., enhancing antioxidant activity, improving cognition and dementia, controlling weight, and preventing multiple sclerosis, diabetes complication, and cancer). The literature searching was conducted in PubMed, Embase, Cochrane Library, Web of Science, and SCOPUS from inception to 20 May 2021. It had showed that endogenous LA was exhausted in the process of I/R, which further aggravated I/R injury. Thus, supplements with LA timely (especially pretreatments) may be the prospective way to prevent I/R injury. Recently, studies had demonstrated that LA supplements significantly attenuated I/R injuries of many organs, though clinic investigations were short at present. Hence, it was urgent to summarize these progresses about the effects of LA on different I/R organs as well as the potential mechanisms, which would enlighten further investigations and prepare for clinic applications in the future.

Piperlongumine attenuates oxidative stress, inflammatory, and apoptosis through modulating the GLUT-2/4 and AKT signaling pathway in streptozotocin-induced diabetic rats

The current study was done to measure the role of piperlongumine (PL) on hyperglycemia interrelated oxidative stress-mediated inflammation and apoptosis, inflammatory stress, and the diabetic insulin receptor substrate 2 (IRS2), protein kinase B (AKT), and glucose transporter 2 (GLUT-2)/4 signaling pathway in streptozotocin (STZ)-persuaded diabetic animals. Diabetes was initiated in experimental animals via a single dose intraperitoneal inoculation of STZ. Diabetic rats revealed an augmented blood-glucose level with drastically diminished plasma-insulin status. The functions of antioxidants were diminished with enhanced lipid peroxidation, conjugated dienes, and protein carbonyls noticed in diabetic rats'  plasma and pancreatic tissues. An elevation of nuclear factor-κB (NF-κB), tumor necrosis factor-α, and interleukin-6 proteins was noticed in pancreatic tissues as well as IRS2, AKT, GLUT-2, and GLUT-4 marker expressions were quantified in the hepatic tissue of control and diabetic rats. Oral administration of PL for 30 days drastically lowered glucose and higher insulin status in STZ-induced diabetic rats. Impressively, PL oral supplementation considerably restored the antioxidant levels and reduced inflammation and diabetic marker expressions in STZ-diabetic rats. These results were supported through a histological study. Moreover, PL also augmented the level of B-cell lymphoma 2 and diminished the level of Bcl-2-associated X protein in STZ-treated rat's hepatic tissues. Thus, we concluded that PL excellently rescued pancreatic β cells through mitigating hyperglycemia via dynamic insulin secretion, activating antioxidants, and inhibiting inflammation and apoptosis in the pancreatic and hepatic tissue of diabetic rats.

The Phenolic Antioxidant 3,5-dihydroxy-4-methoxybenzyl Alcohol (DHMBA) Prevents Enterocyte Cell Death under Oxygen-Dissolving Cold Conditions through Polyphyletic Antioxidant Actions

Cold preservation in University of Wisconsin (UW) solution is not enough to maintain the viability of the small intestine, due to the oxidative stress. The novel phenolic antioxidant 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA) has dual properties to reduce oxidative stress, radical scavenging, and antioxidant protein induction, in other cells. This study was designed to determine whether DHMBA reduces cold preservation injury of enterocytes, and to identify the effector site. Enterocytes were subjected to 48-h cold preservation under atmosphere in UW solution (±DHMBA), and then returned to normal culture to replicate reperfusion of the small intestine after cold preservation. At the end of cold preservation (ECP) and at 1, 3, 6, and 72 h after rewarming (R1h, R3h, R6h, and R72h), we evaluated cell function and the injury mechanism. The results showed that DHMBA protected mitochondrial function mainly during cold preservation, and suppressed cell death after rewarming, as shown by the MTT, ATP, mitochondrial membrane potential, LDH, and lipid peroxidation assays, together with enhanced survival signals (PI3K, Akt, p70S6K) and induction of antioxidant proteins (HO-1, NQO-1, TRX-1). We found that DHMBA mitigates the cold-induced injury of enterocytes by protecting the mitochondria through direct and indirect antioxidative activities.

Amelioration of Metal-Induced Cellular Stress by α-Lipoic Acid and Dihydrolipoic Acid through Antioxidative Effects in PC12 Cells and Caco-2 Cells

α-Lipoic acid (ALA) and its reduced form dihydrolipoic acid (DHLA) are endogenous dithiol compounds with significant antioxidant properties, both of which have the potential to detoxify cells. In this study, ALA (250 μM) and DHLA (50 μM) were applied to reduce metal (As, Cd, and Pb)-induced toxicity in PC12 and Caco-2 cells as simultaneous exposure. Both significantly decreased Cd (5 μM)-, As (5 μM)-, and Pb (5 μM)-induced cell death. Subsequently, both ALA and DHLA restored cell membrane integrity and intracellular glutathione (GSH) levels, which were affected by metal-induced toxicity. In addition, DHLA protected PC12 cells from metal-induced DNA damage upon co-exposure to metals. Furthermore, ALA and DHLA upregulated the expression of survival-related proteins mTOR (mammalian target of rapamycin), Akt (protein kinase B), and Nrf2 (nuclear factor erythroid 2-related factor 2) in PC12 cells, which were previously downregulated by metal exposure. In contrast, in Caco-2 cells, upon co-exposure to metals and ALA, Nrf2 was upregulated and cleaved PARP-1 (poly (ADP-ribose) polymerase-1) was downregulated. These findings suggest that ALA and DHLA can counterbalance the toxic effects of metals. The protection of ALA or DHLA against metal toxicity may be largely due to an enhancement of antioxidant defense along with reduced glutathione level, which ultimately reduces the cellular oxidative stress.

Alpha lipoic acid inhibits oxidative stress-induced apoptosis by modulating of Nrf2 signalling pathway after traumatic brain injury

Alpha lipoic acid (ALA) is a powerful antioxidant which has been widely used in the treatment of different system diseases, such as cardiovascular and cerebrovascular diseases. But, there are few studies that refer to protective effects and potential mechanisms on traumatic brain injury (TBI). This study was carried out to investigate the neuroprotective effect following TBI and illuminate the underlying mechanism. Weight drop‐injured model in rats was induced by weight‐drop. ALA was administrated via intraperitoneal injection after TBI. Neurologic scores were examined following several tests. Neurological score was performed to measure behavioural outcomes. Nissl staining and TUNEL were performed to evaluate the neuronal apoptosis. Western blotting was engaged to analyse the protein content of the Nuclear factor erythroid 2‐related factor 2 (Nrf2) and its downstream protein factors, including hemeoxygenase‐1 (HO‐1) and quinine oxidoreductase‐1 (NQO1). ALA treatment alleviated TBI‐induced neuron cell apoptosis and improved neurobehavioural function by up‐regulation of Nrf2 expression and its downstream protein factors after TBI. This study presents new perspective of the mechanisms responsible for the neuronal apoptosis of ALA, with possible involvement of Nrf2 pathway.

Ebselen protects rat hearts against myocardial ischemia-reperfusion injury

Ebselen is an organoselenium compound that has demonstrated potent antioxidant and anti-inflammatory effects in previous studies. The present study was conducted to evaluate the effect of ebselen on myocardial ischemia-reperfusion (I/R) injury in a rat model and to elucidate the related mechanisms. Myocardial infarct size was assessed using triphenyltetrazolium chloride staining. Myocardial injury was evaluated according to the histopathological and ultrastructural alterations of rat hearts and the serum activity levels of cardiac enzymes, including creatine kinase (CK), CK-MB isoenzyme and lactate dehydrogenase (LDH). Cardiomyocyte apoptosis was detected using the terminal dUTP nick end-labelling (TUNEL) assay. In addition, the expression of apoptosis-associated proteins was measured using western blot analysis. In heart tissue specimens the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), and levels of malondialdehyde (MDA) and protein carbonyl (PC) were also detected. The results indicated that ebselen reduced I/R-induced increase in myocardial infarct size and prevented the I/R-induced decreases in ejection fraction and fractional shortening. Further of note, ebselen improved I/R-induced rat heart injury. This was indicated by attenuation of histological and ultrastructural changes; reduction of serum CK, CK-MB and LDH activity levels; and decreased cell apoptosis on TUNEL staining, which was verified by decreased expression of cleaved (C)-Caspase-8, C-Caspase-3, B-cell lymphoma 2 (Bcl-2)-associated X protein and C-PARP, and increased expression of Bcl-2. Additionally, SOD and GPx activity levels were significantly higher, while MDA and PC levels were significantly lower in the ebselen + I/R group compared with in the I/R group. In conclusion, the present results suggested that ebselen serves an important role in protecting against myocardial I/R injury. The underlying mechanism may involve suppression of cardiomyocyte apoptosis and promotion of antioxidant activity.

Alpha Lipoic Acid: A Therapeutic Strategy that Tend to Limit the Action of Free Radicals in Transplantation

Organ replacement is an option to mitigate irreversible organ damage. This procedure has achieved a considerable degree of acceptance. However, several factors significantly limit its effectiveness. Among them, the initial inflammatory graft reaction due to ischemia-reperfusion injury (IRI) has a fundamental influence on the short and long term organ function. The reactive oxygen species (ROS) produced during the IRI actively participates in these adverse events. Therapeutic strategies that tend to limit the action of free radicals could result in beneficial effects in transplantation outcome. Accordingly, the anti-oxidant α-lipoic acid (ALA) have been proved to be protective in several animal experimental models and humans. In a clinical trial, ALA was found to decrease hepatic IRI after hepatic occlusion and resection. Furthermore, the treatment of cadaveric donor and recipient with ALA had a protective effect in the short-term outcome in simultaneous kidney and pancreas transplanted patients. These studies support ALA as a drug to mitigate the damage caused by IRI and reinforce the knowledge about the deleterious consequences of ROS on graft injury in transplantation. The goal of this review is to overview the current knowledge about ROS in transplantation and the use of ALA to mitigate it.

Inhibitory mechanism against oxidative stress of caffeic acid

The purpose of this article is to summarize the reported antioxidant activities of a naturally abundant bioactive phenolic acid, caffeic acid (CA, 3,4-dihydroxycinnamic acid), so that new avenues for future research involving CA can be explored. CA is abundantly found in coffee, fruits, vegetables, oils, and tea. CA is among the most potential and abundantly found in nature, hydroxycinnamic acids with the potential of antioxidant behavior. Reactive oxygen species produced as a result of endogenous processes can lead to pathophysiological disturbances in the human body. Foods containing phenolic substances are a potential source for free radical scavenging; these chemicals are known as antioxidants. This review is focused on CA’s structure, availability, and potential as an antioxidant along with its mode of action. A brief overview of the literature published about the prooxidant potential of caffeic acid as well as the future perspectives of caffeic acid research is described. CA can be effectively employed as a natural antioxidant in various food products such as oils.

The influence of lipoic acid on caveolin-1-regulated antioxidative enzymes in the mouse model of acute ulcerative colitis

AIM

This study was undertaken to verify if two-weeks treatment of lipoic acid (LA) influence colon damage and pro-inflammatory cytokine synthesis during DSS-induced acute colitis. Moreover, as LA has anti-oxidative properties, we analyzed its influence on the level of antioxidative enzymes, HO-1 and eNOS, and their regulator- caveolin-1.

METHODS

LA was administrated to male C57/BALBc mice at a dose of 25 or 50mg/kg/day (i.p.) for 21days. Acute colitis was induced by administration of 4% DSS (w/v) in drinking water for 5days, followed by 2days of normal drinking water. Mice in LA+DSS groups were treated with LA (25 or 50mg/kg/day; i.p.) starting 14days prior to 4% DSS. Control group received saline for 21days. In the colon tissue we measured myeloperoxidase activity (MPO), IL-1β, IL-6, IL-17A, IL-23 (ELISA method), and tissue level of cav-1, phospho-eNOS, total eNOS and HO-1 (Western blot).

RESULTS

Administration of DSS significantly increased total colon damage (p<0.001), myeloperoxidase (MPO) activity (p<0.05) and pro-inflammatory IL-6 (p<0.05). There was also a tendency towards higher IL-1β, IL-17A, and IL-23 in the colon. LA alone did not influence total colon damage, MPO activity, and pro-inflammatory cytokines concentration compared to control (p<0.05). Notably, mice treated with LA and DSS had significantly decreased total colon damage score (p<0.001), despite augmented colon MPO activity (p<0.01), but similar (IL-17A) or even significantly higher level (IL-1β, IL-23) as compared to the DSS group (p<0.05). IL-6 was insignificantly decreased after LA treatment at a dose of 50mg/kg. In acute colitis there was a tendency towards an increase in cav-1 and HO-1 and a decrease p-eNOS/total eNOS ratio. Moreover, the LA+DSS groups had higher expression of HO-1 and p-eNOS/total eNOS (p<0.05) compared to the DSS group, and a tendency towards higher cav-1 level. The changes did not depend on LA dose.

CONCLUSION

Our study indicated that LA, at lower doses, may influence cav-1-regulated antioxidative enzyme levels (HO-1 and p-eNOS/total eNOS) despite an increase in colon pro-inflammatory cytokine levels during acute colitis. Hence, LA treatment may be - to some extent - beneficial in attenuation of acute colitis.

α-Lipoic acid protects against the cytotoxicity and oxidative stress induced by cadmium in HepG2 cells through regeneration of glutathione by glutathione reductase via Nrf2/ARE signaling pathway

α-Lipoic acid (α-LA) is a potent natural antioxidant, which is capable of regenerating glutathione (GSH). However, the mechanisms by which α-LA regenerates reduced glutathione (rGSH) via the reduction of oxidized glutathione (GSSG) by glutathione reductase (GR) are still not well understood. In the present study, we investigated if α-LA replenished rGSH by GR via Nrf2/ARE signaling pathway in cadmium-treated HepG2 cells. We found that α-LA antagonized the oxidative damage and alleviated the cytotoxicity in cadmium-induced HepG2 cells by regeneration of rGSH. α-LA regenerated rGSH by activating Nrf2 signaling pathway via promoting the nuclear translocation of Nrf2, which upregulates the transcription of GR, and thus increased the activity of GR. Our results indicated that α-LA was an effective agent to antagonize the oxidative stress and alleviate the cytotoxicity in cadmium-treated HepG2 cells by regenerating rGSH through activating Nrf2 signaling pathway.

Induced pluripotent stem cells alleviate lung injury from mesenteric ischemia-reperfusion

BACKGROUND

Mesenteric ischemia-reperfusion (I/R) injury is a serious pathophysiologic process that can trigger the development of multiorgan dysfunction. Acute lung injury is a major cause of death among mesenteric I/R patients, as current treatments remain inadequate. Stem cell-based therapies are considered novel strategies for treating several devastating and incurable diseases. This study examined whether induced pluripotent stem cells (iPSCs) lacking c-myc (i.e., induced using only the three genes oct4, sox2, and klf4) can protect against acute lung injury in a mesenteric I/R mouse model.

METHODS

C57BL/6 mice were randomly divided into the following groups: sham/no treatment, vehicle treatment with phosphate-buffered saline, treatment with iPSCs, and treatment with iPSC-conditioned medium. The mice were subjected to mesenteric ischemia for 45 minutes followed by reperfusion for 24 hours. After I/R, the lungs and the ileum of the mice were harvested. Lung injury was evaluated by histology, immunohistochemistry, and analyses of the levels of inflammatory cytokines, cleaved caspase 3, and 4-hydroxynonenal.

RESULTS

The intravenously delivered iPSCs engrafted to the lungs and the ileum in response to mesenteric I/R injury. Compared with the phosphate-buffered saline-treated group, the iPSC-treated group displayed a decreased intensity of acute lung injury 24 hours after mesenteric I/R. iPSC transplantation significantly reduced the expression of proinflammatory cytokines, oxidative stress markers, and apoptotic factors in injured lung tissue and remarkably enhanced endogenous alveolar cell proliferation. iPSC-conditioned medium treatment exerted a partial effect compared with iPSC treatment.

CONCLUSION

When considering the anti-inflammatory, antioxidant, and antiapoptotic properties of iPSCs, the transplantation of iPSCs may represent an effective treatment option for mesenteric I/R-induced acute lung injury.

Tramadol alleviates myocardial injury induced by acute hindlimb ischemia reperfusion in rats

Background

Organ injury occurs not only during periods of ischemia but also during reperfusion. It is known that ischemia reperfusion (IR) causes both remote organ and local injuries.

Objective

This study evaluated the effects of tramadol on the heart as a remote organ after acute hindlimb IR.

Methods

Thirty healthy mature male Wistar rats were allocated randomly into three groups: Group I (sham), Group II (IR), and Group III (IR + tramadol). Ischemia was induced in anesthetized rats by left femoral artery clamping for 3 h, followed by 3 h of reperfusion. Tramadol (20 mg/kg, intravenous) was administered immediately prior to reperfusion. At the end of the reperfusion, animals were euthanized, and hearts were harvested for histological and biochemical examination.

Results

The levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were higher in Groups I and III than those in Group II (p < 0.05). In comparison with other groups, tissue malondialdehyde (MDA) levels in Group II were significantly increased (p < 0.05), and this increase was prevented by tramadol. Histopathological changes, including microscopic bleeding, edema, neutrophil infiltration, and necrosis, were scored. The total injuryscore in Group III was significantly decreased (p < 0.05) compared with Group II.

Conclusion

From the histological and biochemical perspectives, treatment with tramadol alleviated the myocardial injuries induced by skeletal muscle IR in this experimental model.

Protective effects of thymoquinone and melatonin on intestinal ischemia-reperfusion injury

BACKGROUND/AIM

In the present study, we aimed to compare the potential protective effects of thymoquinone and melatonin by using equivalent dose, on oxidative stress-induced ischemia-reperfusion (IR) injury in the intestinal tissue of rats.

MATERIALS AND METHODS

The study was performed using 32 male Wistar-Albino rats (weighing 180-200 g) randomly divided into four groups: Group I, sham group; Group II, IR group; Group III, IR with melatonin group; and Group IV, IR with thymoquinone group. After laparotomy, ischemia and reperfusion were performed for 60 and 120 min, respectively, on all the groups. Intestinal tissue sections were stained using routine histological methods and examined under the light microscope. In addition, the sections were immunohistochemically stained using the TUNEL method for determination of apoptosis. Superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, and malondialdehyde (MDA) levels in the intestinal tissue were also measured.

RESULTS

The IR group had significantly elevated tissue SOD activity, GSH-Px activity, and MDA levels compared with the sham group. Administration of thymoquinone and melatonin efficiently reduced these increases. Statistically significant number of apoptotic cells was observed in the intestinal tissue of IR group rats compared with the sham group. Treatment with thymoquinone and melatonin markedly reduced the number of apoptotic cells.

CONCLUSION

The effects of melatonin and thymoquinone on IR-induced oxidative stress in rat intestines were similar. Our findings suggest that melatonin and thymoquinone protect against IR-induced injury to intestinal tissues.

Effects of ebselen on radiocontrast media–induced hepatotoxicity in rats

Oxidative stress is accepted as a potential responsible mechanism in the pathogenesis of radiocontrast media (RCM)-induced hepatotoxicity. Therefore, we aimed to investigate the protective effects of ebselen against RCM-induced hepatotoxicity by measuring tissue oxidant/antioxidant parameters and histological changes in rats. Wistar albino rats were randomly separated into four groups consisting of eight rats per group. Normal saline was given to the rats in control group (group 1). RCM was given to the rats in group 2, and both RCM and ebselen were given to the rats in group 3. Only ebselen was given to the rats in group 4. Liver sections of the killed animals were analyzed to measure the levels of malondialdehyde (MDA) and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), as well as histopathological changes. In RCM group, SOD and CAT levels were found increased. In RCM-ebselen group, MDA, SOD and CAT levels were found decreased. In RCM-ebselen group, however, GSH-Px activities of liver tissue increased. All these results indicated that ebselen produced a protective mechanism against RCM-induced hepatotoxicity and took part in oxidative stress.

α-Lipoic acid, a scavenging agent for H₂O₂, reduces ethanol-stimulated locomotion in mice

RATIONALE

The main system of central ethanol oxidation is mediated by the enzyme catalase. By reacting with H(2)O(2), brain catalase forms compound I (the catalase-H(2)O(2) system), which is able to oxidize ethanol to acetaldehyde in the brain. Previous studies have demonstrated that pharmacological manipulations of brain catalase activity modulate the stimulant effects of ethanol in mice. However, the role of H(2)O(2) in the behavioral effects of ethanol has not yet been clearly addressed.

OBJECTIVES

In the present study, we investigated the effects of alpha-lipoic acid (LA), a scavenging agent for H(2)O(2), on ethanol-induced locomotor stimulation.

METHODS

CD-1 mice were pretreated with LA [0-100 mg/kg, intraperitoneally (IP)] 0-60 min prior to administration of ethanol (0-3.75 g/kg, IP). In another experiment, animals were pretreated with LA (0, 25, or 50 mg/kg, IP) 30 min before cocaine (10 mg/kg, IP), amphetamine (2 mg/kg, IP), or caffeine (25 mg/kg, IP). After these treatments the animals were placed in an open-field chamber and their locomotor activity was measured for 20 min.

RESULTS

LA 25, 50, and 100 mg/kg IP prevented ethanol-induced locomotor stimulation. LA did not affect the locomotor-stimulating effects of cocaine, amphetamine, and caffeine. Additionally, we demonstrated that LA prevents the inactivation of brain catalase by 3-amino-1,2,4-triazole, thus indicating that H(2)O(2) levels are reduced by LA.

CONCLUSIONS

These data support the idea that a decrease in cerebral H(2)O(2) production by LA administration inhibits ethanol-stimulated locomotion. This study suggests that the brain catalase-H(2)O(2) system, and by implication centrally formed acetaldehyde, plays a key role in the psychopharmacological effects of ethanol.

Total oxidant status and oxidative stress are increased in infants with necrotizing enterocolitis

BACKGROUND

Oxidative stress has been implicated in the pathogenesis of necrotizing enterocolitis (NEC). In this study, we compared the global oxidant/antioxidant status by measuring total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) in preterm infants with NEC and with control preterms.

METHODS

Forty-one preterm neonates with NEC (stage 1 [group 1; n = 23] and stages 2 and 3 [group 2; n = 18]) and age-matched 36 healthy preterm controls (group 3) were included in this study. Blood samples were obtained both at the time of NEC diagnosis and 72 hours after for the evaluation of TAC and TOS. Serum levels of TAC, TOS, and OSI in patients with NEC were compared with controls.

RESULTS

Demographic characteristics were comparable in all 3 groups. Preterm neonates in group 2 (with stages 2 and 3 NEC) had the highest TOS levels and OSI (P < .001 vs both groups 1 and 3). There was no difference in TAC levels among the groups (P = .26).

CONCLUSIONS

Our findings demonstrated that although TAC levels were similar in all 3 groups, oxidant stress mechanisms were activated in preterm neonates with definite NEC (stages 2 and 3 NEC). Premature neonates with increased levels of TOS and OSI were associated with severity of NEC.

Effect of surgical stress on nuclear and mitochondrial DNA from healthy sections of colon and rectum of patients with colorectal cancer

Surgical resection at any location in the body leads to stress response with cellular and subcellular change, leading to tissue damage. The intestine is extremely sensitive to surgical stress with consequent postoperative complications. It has been suggested that the increase of reactive oxygen species as subcellular changes plays an important role in this process. This article focuses on the effect of surgical stress on nuclear and mitochondrial DNA from healthy sections of colon and rectum of patients with colorectal cancer. Mitochondrial DNA copy number, mitochondrial common deletion and nuclear and mitochondrial 8-oxo-2'-deoxyguanosine content were measured. Both the colon and rectal tissue were significantly damaged either at the nuclear or mitochondrial level. In particular, mitochondrial DNA was more damaged in rectum than in colon. The present investigation found an association between surgical stress and nuclear and mitochondrial DNA damage, suggesting that surgery may generate an increase in free radicals, which trigger a cascade of molecular changes, including alterations in DNA.

Beneficial effects of N-acetylcysteine and ebselen on renal ischemia/reperfusion injury

INTRODUCTION

It has been demonstrated that peroxynitrite accompanies acute renal ischemia and contributes to the pathophysiology of renal damage. Therefore, we aimed to investigate the roles of N-acetylcysteine (NAC), a well-known powerful antioxidant, and ebselen (E), a scavenger of peroxynitrite, on renal injury induced by renal ischemia/reperfusion injury (IRI) of rat kidney.

MATERIALS AND METHODS

Forty male Sprague-Dawley rats were divided into five groups: sham, renal IRI, renal IRI+NAC, renal IRI+E, and renal IRI+NAC+E. IR injury was induced by 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood samples were obtained for histopathological and biochemical evaluations.

RESULTS

Renal IR resulted in increased malondialdehyde and nitrite/nitrate levels suggesting increased lipid peroxidation and peroxynitrite production and decreased superoxide dismutase and glutathione peroxidase activities. Both NAC and E alone significantly decreased malondialdehyde and nitrite/nitrate levels and increased superoxide dismutase and glutathione peroxidase activities. Additionally in the renal IRI+NAC+E group, all biochemical results were quite close to those of sham group. Histopathologically, the kidney injury in rats treated with combination of NAC and E was found significantly less than the other groups.

CONCLUSIONS

Both NAC and E are able to ameliorate IRI of the kidney by decreasing oxidative and nitrosative stresses and increasing free radical scavenger properties. Additionally, combination of NAC and E prevents kidney damage more than when each drug is used alone, suggesting that scavenging peroxynitrite nearby antioxidant activity is important in preventing renal IRI.

Sulforaphane protects liver injury induced by intestinal ischemia reperfusion through Nrf2-ARE pathway

AIM: To investigate the effect of sulforaphane (SFN) on regulation of NF-E2-related factor-2 (Nrf2)-antioxidant response element (ARE) pathway in liver injury induced by intestinal ischemia/reperfusion (I/R).

METHODS: Rats were divided randomly into four experimental groups: control, SFN control, intestinal I/R and SFN pretreatment groups (n = 8 in each group). The intestinal I/R model was established by clamping the superior mesenteric artery for 1 h and 2 h reperfusion. In the SFN pretreatment group, surgery was performed as in the intestinal I/R group, with intraperitoneal administration of 3 mg/kg SFN 1 h before the operation. Intestine and liver histology was investigated. Serum levels of aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were measured. Liver tissue superoxide dismutase (SOD), myeloperoxidase (MPO), glutathione (GSH) and glutathione peroxidase (GSH-Px) activity were assayed. The liver transcription factor Nrf2 and heme oxygenase-1 (HO-1) were determined by immunohistochemical analysis and Western blotting analysis.

RESULTS: Intestinal I/R induced intestinal and liver injury, characterized by histological changes as well as a significant increase in serum AST and ALT levels (AST: 260.13 ± 40.17 U/L vs 186.00 ± 24.21 U/L, P < 0.01; ALT: 139.63 ± 11.35 U/L vs 48.38 ± 10.73 U/L, P < 0.01), all of which were reduced by pretreatment with SFN, respectively (AST: 260.13 ± 40.17 U/L vs 216.63 ± 22.65 U/L, P < 0.05; ALT: 139.63 ± 11.35 U/L vs 97.63 ± 15.56 U/L, P < 0.01). The activity of SOD in the liver tissue decreased after intestinal I/R (P < 0.01), which was enhanced by SFN pretreatment (P < 0.05). In addition, compared with the control group, SFN markedly reduced liver tissue MPO activity (P < 0.05) and elevated liver tissue GSH and GSH-Px activity (P < 0.05, P < 0.05), which was in parallel with the increased level of liver Nrf2 and HO-1 expression.

CONCLUSION: SFN pretreatment attenuates liver injury induced by intestinal I/R in rats, attributable to the antioxidant effect through Nrf2-ARE pathway.

Potential utility of full-spectrum antioxidant therapy, citrulline, and dietary nitrate in the management of sickle cell disease

There is considerable evidence that oxidative stress and a loss of nitric oxide bioactivity are key mediators of the vasculopathies associated with sickle cell disease. A comprehensive nutraceutical strategy for mitigating the contribution of oxidative stress to pathogenesis - dubbed "full-spectrum antioxidant therapy" - may have utility in this syndrome. This strategy entails concurrent administration of phycocyanobilin - a phytochemical richly supplied by spirulina, shown to inhibit NADPH oxidase in a manner analogous to its chemical relatives biliverdin and bilirubin; high-dose folate - recently shown to quench peroxynitrite-derived radicals and restore coupling of NO synthase; N-acetylcysteine - for boosting intracellular glutathione levels; and a phase 2 inducer such as lipoic acid - to further promote glutathione synthesis while increasing expression of antioxidant enzymes. Suboptimal endothelial arginine levels, reflecting increased plasma arginase activity and elevated ADMA, contribute to the loss of NO bioactivity in sickle cell disease; supplementation with the arginine precursor citrulline may ameliorate this defect. Increased intakes of plant-derived nitrate have the potential to diminish the quenching of NO by plasma hemoglobin in sickle cell patients, while boosting systemic NO production independent of NO synthase activity. In addition to the well-documented utility of hydroxyurea - possibly a suboptimal strategy for life-long therapy owing to its mutagenic activity - rational pharmaceutical options for managing sickle cell disease include pentoxifylline and phosphodiesterase 5 inhibitors such as sildenafil.

Comparison of the efficacy of melatonin and 1400W on renal ischemia/reperfusion injury: a role for inhibiting iNOS

INTRODUCTION

We investigated the roles of melatonin (a powerful antioxidant, iNOS inhibitor, and a scavenger of peroxynitrite) and 1400W (a strong and selective inhibitor of inducible nitric oxide) on renal dysfunction and injury induced by ischemia/reperfusion (I/R) of rat kidney, since oxidative and nitrosative injury are believed to be the major causes.

MATERIALS AND METHODS

Thirty-two male Sprague-Dawley rats were divided into four groups of sham-operated, I/R, I/R + Melatonin and I/R + 1400W. Rats were given either melatonin (10 mg/kg) or 1400W (10 mg/kg) in the I/R + Melatonin and I/R + 1400W groups respectively at 6 h prior to ischemia and at the beginning of reperfusion via intraperitoneal route. I/R injury was induced by 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for histopathologic and biochemical evaluation.

RESULTS

Melatonin and 1400W had an ameliorative effect on both oxidative and nitrosative stress in the kidneys against renal I/R injury in rats. In addition, melatonin significantly reduced elevated nitro-oxidative stress product, restored decreased antioxidant enzymes and attenuated histological alterations when compared with 1400W.

CONCLUSIONS

Both Melatonin and 1400W were efficient in ameliorating experimental I/R injury of the kidneys. Moreover, melatonin was more effective than 1400W possibly through inhibiting iNOS as well as scavenging free oxygen radicals and peroxynitrite.

Proanthocyanidin protects intestine and remote organs against mesenteric ischemia/reperfusion injury

BACKGROUND

Intestinal ischemia/reperfusion (IR) induces a systemic inflammatory response and releases harmful substances that may affect the function and integrity of distant organs such as lung, liver, and kidney. We conducted this study to find out if proanthocyanidins (PA) has protective effects against mesenteric IR injury and mesenteric IR-induced intestinal and distant organ injury.

MATERIALS AND METHODS

Thirty-two Sprague-Dawley rats were divided into four groups: control, control + PA, IR, IR + PA. The IR and IR + PA groups were subjected to mesenteric arterial ischemia for 60 min and reperfusion for 6 h. The Control + PA and IR + PA groups were administered PA (100 mg/kg/day via oral gavage) for 7 days prior to injury insult. We collected ileal and distant organ tissues, such as pulmonary, hepatic, and kidney specimens to measure tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), and nitrite plus nitrate (NO(x)), and we then evaluated histological changes.

RESULTS

In the IR group, significant increases in MDA and NO(x) levels and significant increases in SOD and GPx activities of intestine, liver, kidney, and lung were observed. The MDA and NO(x) levels were significantly lower, as were the SOD and GPx activities in the IR + PA group than that in the IR group. Although the intestine and distant organs damage scores were significantly higher in the IR group, these injuries were prevented by PA in the IR + PA group.

CONCLUSIONS

This study demonstrates that PA has a significant effect in the protection of the intestine and the remote organs against mesenteric IR injury.

Medical ozone therapy reduces oxidative stress and intestinal damage in an experimental model of necrotizing enterocolitis in neonatal rats

PURPOSE

Necrotizing enterocolitis (NEC) remains a major cause of morbidity and death in neonates. Evidence suggests that an imbalance between activated proinflammatory response with inadequate antiinflammatory protection results in NEC. Ozone has been proposed as an antioxidant enzyme activator, immunomodulator, and cellular metabolic activator. Therefore, this study was designed to investigate whether medical ozone therapy is effective on neonatal rat model of NEC.

MATERIALS AND METHODS

Thirty-eight newborn Sprague-Dawley pups were randomly divided into 3 groups of NEC, NEC + ozone, and control (left to breast feed). Necrotizing enterocolitis was induced by enteral formula feeding and exposure to 100% carbon dioxide inhalation for 10 minutes after +4 degrees C cold exposures for 5 minutes and 97% oxygen for 5 minutes 2 times daily. The NEC + ozone group received 0.7 mg/kg per day ozone/oxygen mixture intraperitoneally for a total of 3 days after first day of NEC procedure. The pups were killed at fourth day, and their intestinal tissues were harvested for biochemical and histopathologic analysis. Blood sample from pups were also obtained.

RESULTS

The mortality rate and the weight loss were significantly higher in NEC group than control and treatment groups. Oxidative stress markers (malondialdehyde and protein carbonyl content) significantly increased and antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase) were significantly decreased in NEC group. All these biochemical changes were ameliorated in NEC + ozone group. Nitrate plus nitrite levels and serum tumor necrosis factor alpha were elevated in NEC group and reduced in treatment group. In addition, histopathologic injury score of NEC group was significantly higher than NEC + ozone group.

CONCLUSION

Ozone treatment significantly reduced the severity of NEC by modulating antioxidative defense and antiinflammatory protection in our experimental animal model.

Protective effect of sulfhydryl-containing antioxidants against ischemia/reperfusion injury of prepubertal rat intestine

BACKGROUND AND AIM

Reactive oxygen species generated during reperfusion of the tissue are known to play an important role in the basic pathophysiology of ischemia/reperfusion (I/R) injury. The aim of this study was to investigate and compare the protective effects of three sulfide-based antioxidants, N-acetylcysteine (NAC), erdosteine (ERD), and alpha-lipoic acid (LA), on I/R injury of the small intestine tissue.

METHODS

Forty male Sprague-Dawley rats weighing between 100-150 g were divided into five groups (n = 8 for each): control (sham operated), I/R, I/R + NAC, I/R + ERD, and I/R + LA. Intestinal ischemia was provided by occluding the superior mesenteric artery via a special microvascular clamp; ischemia for 30 min and reperfusion for 3 days were carried out. Ileal specimens were obtained to determine the tissue levels of malondialdehyde (MDA), protein carbonyl contents (PCO), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities and histological changes.

RESULTS

The rats subjected to intestinal I/R exhibited an increase in tissue MDA and PCO; the levels could hardly be ameliorated in the treatment groups. SOD and GPx activities were significantly decreased in the I/R group, whereas their reduction was less expressed in the treatment groups. Additionally, the histopathological injury scores of the disulfide-treated groups were lower than those of the I/R group.

CONCLUSION

All of the sulfhydryl-containing antioxidants used in this study exhibited a significant role in attenuating intestinal I/R injury; however, the outcome of the LA-treated group was significantly marked than that of the others.

Erdosteine and ebselen as useful agents in intestinal ischemia/reperfusion injury

BACKGROUND

Reactive oxygen and nitrogen species generated during reperfusion of the tissue are characteristic of ischemia/reperfusion (I/R) injury. The purpose of the present study was to investigate whether erdosteine and ebselen, molecules with antioxidant properties and peroxynitrite scavenging capability, respectively, can reduce oxidative stress and histological damage in the rat small bowel subjected to mesenteric I/R injury.

MATERIALS AND METHODS

Forty Sprague-Dawley rats were divided into five groups equally: sham, I/R, I/R plus erdosteine, I/R plus ebselen, and I/R plus erdosteine and ebselen. Intestinal ischemia for 45 min and reperfusion for 3 d were carried out. Ileal specimens were obtained to determine the tissue levels of malondialdehide (MDA), protein carbonyl content (PCC), superoxide dismutase (SOD), glutathione peroxidase (GPx), nitrite/nitrate (NO(x)) level and histological changes.

RESULTS

Intestinal I/R resulted in increased tissue MDA, PCC, and NO(x) levels and decreased SOD and GPx activities. Both erdosteine and ebselen alone significantly decreased MDA, PCC, and NO(x) levels and increased antioxidant enzymes activities, but all values were different from control. These changes almost returned to control values in the group treated with erdostein and ebselen. Histopathologically, the intestinal injury in rats treated with erdosteine and ebselen as well as combination were less than I/R group.

CONCLUSIONS

Both erdosteine and ebselen were able to attenuate I/R injury of the intestine via inhibition of lipid peroxidation and protein oxidation, maintenance of antioxidant, and free radical scavenger properties. Nevertheless, combination treatment showed more promising results, suggesting that scavenging peroxynitrite nearby antioxidant activity is important in preventing intestinal I/R injury.