The protective effects of physiological and pharmacological concentrations of melatonin on renal ischemia-reperfusion injury in rats

Reactive oxygen species have been implicated in the pathophysiology of renal ischemia reperfusion (I/R) injury. The pineal secretory product melatonin is known to be a potent free radical scavenger and antioxidant. This study was designed to investigate the effects of physiological and pharmacological concentrations of melatonin on I/R injury. Rats were pinealectomized (Px) or sham-operated (control) 2 months before the I/R studies. There were eight groups of eight rats each. After a right nephrectomy to produce damage, left renal vessels were occluded for 60 min, followed by 24 h reperfusion, in rats. Malondialdehyde (MDA) levels resulting from I/R were significantly higher in the pinealectomized rats than in the control group. Melatonin administration (4 mg kg(-1) i.p. either before ischemia or reperfusion) to Px and sham-operated rats significantly reduced the MDA values and returned them to the control values. Morphological changes in the groups were similar to the MDA levels. Serum levels of blood urea nitrogen and creatine were unchanged. These results suggest that physiological and pharmacological melatonin concentrations are important for the reduction of I/R-induced damage. We also demonstrated that melatonin, even when administrated just before reperfusion, had a protective effect on I/R injury. It would seem valuable to test melatonin in clinical trials for the prevention of possible I/R injury.     

Pyrrolidine dithiocarbamate prevents 60 minutes of warm mesenteric ischemia/reperfusion injury in rats

BACKGROUND: Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, destructive effects of reperfusion injury has been demonstrated. In this study, we aimed to investigate whether PDTC prevents harmful effects of superior mesenteric I/R injury in rats. METHODS: Wistar-albino rats were randomly allocated into the following 4 groups: (1) sham-operated group--these animals underwent laparotomy without I/R injury (group I, n = 12); (2) sham+PDTC group--identical to sham-operated rats except for the administration of PDTC (100 mg/kg intravenous bolus) 30 minutes prior to the commencement of the experimental period (group II, n = 12); (3) I/R group--these animals underwent laparotomy and 60 minutes of ischemia followed by 120 minutes of reperfusion (group III, n = 12); (4) PDTC-treated group (100 mg/kg, intravenously, before the I/R, group IV, n = 12). All animals were killed, and intestinal tissue samples were obtained for investigation of intestinal mucosal injury, myeloperoxidase (MPO) activity, malondialdehyde (MDA) levels, glutathione (GSH) levels, and intestinal edema. RESULTS: There was a statistically significant decrease in GSH levels, along with an increase in intestinal mucosal injury scores, MPO activity, MDA levels, and intestinal tissue wet-to-dry weight ratios in group III when compared to groups I, II, and IV (P < .05). However, PDTC treatment led to a statistically significant increase in GSH levels, along with a decrease in intestinal mucosal injury scores, MPO activity, MDA levels, and intestinal tissue wet-to-dry weight ratios in group IV (P < .05). CONCLUSIONS: This study showed that PDTC treatment significantly prevented the reperfusion injury caused by superior mesenteric I/R. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to use in particular operations where the reperfusion injury occurs.     

Protective effects of glucagon-like peptide 2 on intestinal ischemia-reperfusion rats

Our objective was to evaluate the protective effects of glucagon-like peptide 2 (GLP-2) on intestinal ischemia/reperfusion (I/R) rats. Thirty-two rats were randomly assigned to four experimental groups, each of 8: Group A, sham rats underwent laparotomy only, without superior mesenteric artery (SMA) occlusion; Group B, I/R animals underwent laparotomy and occlusion of the SMA for 60 minutes followed by 120 minutes of reperfusion; Group C, I/R animals underwent intestinal I/R, and received pretreatment with GLP-2 for 3 days preoperatively; and Group D, I/R animals underwent intestinal I/R, received pretreatment with GLP-2 as above, and during the reperfusion phase were injected intravenously with GLP-2. After the reperfusion of intestinal ischemia, samples of intestinal mucosa, mesenteric lymph nodes (MLN) and blood were prepared for determination. In the pretreatment rats with GLP-2 (group C), Chiu's scores, bacterial colony counts, serum D-lactate, intestinal mucosal MDA and ET-1, and serum endotoxin, TNF-alpha and IL-6 were significantly reduced compared with intestinal I/R rats (group B). Administration of GLP-2 during the reperfusion phase following pretreatment (group D) showed further protective effects in comparison with the pretreatment rats (group C). We conclude that treatment with GLP-2 attenuates intestinal I/R injury, reduces bacterial translocation, inhibits the release of oxygen free radicals and ET-1, and may well inhibit the production of proinflammatory cytokines.     

Protective Effect of Melatonin Against Ischemia/Reperfusion-Induced Oxidative Remote Organ Injury in the Rat

Purpose Oxygen free radicals are considered to be important components involved in the pathophysiological tissue alterations observed during ischemia/reperfusion (I/R). Based on the potent antioxidant effects of melatonin, we investigated the putative protective role of melatonin against I/R-induced oxidative remote organ injury.Methods Wistar albino rats were subjected to 1 h of infrarenal aortic occlusion followed by 1 h of reperfusion to induce I/R damage. Melatonin (10 mg/kg, s.c.) or vehicle was administered twice, 15 min prior to ischemia and immediately before the reperfusion period (I/R + Mel or I/R groups). At the end of the reperfusion periods, the rats were decapitated and hepatic, ileal, and lung tissue samples were removed for biochemical analyses of: malondialdehyde (MDA), an end product of lipid peroxidation; the glutathione (GSH) levels, a key antioxidant; and the myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. The serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured to evaluate the liver function. The wet/dry lung weight ratio was calculated to determine the extent of lung damage.Results The results revealed the occurrence of I/R-induced oxidative organ damage, as evidenced by increases in the MDA and MPO activity, and a decrease in GSH. Furthermore the AST, ALT levels, and the wet/dry lung weight ratio, which all increased due to I/R, were all observed to decrease after melationin treatment.Conclusion Since melatonin administration reversed these oxidant responses, it seems likely that melationin has a protective effect against oxidative organ damage induced by I/R.     

The effect of remote ischemic preconditioning on healing of colonic anastomoses

BACKGROUND: We aimed to investigate the potential protective effect of remote ischemic preconditioning (IPC) on delayed colonic anastomotic healing induced by remote ischemia and reperfusion (I/R) injury. MATERIALS AND METHODS: Forty male Wistar rats were randomly assigned into four groups, each consisting of 10 rats: the control group (C), the remote I/R group [I/R, 40 min of superior mesenteric artery (SMA) occlusion], the preconditioned I/R group (IPC, two cycles of 5 min temporary occlusion of SMA before an ischemic insult of 40 min), and the preconditioned group (PC, two cycles of 5 min temporary occlusion of SMA). Colonic anastomosis was performed immediately after the ischemic insult. Anastomotic healing was assessed on postoperative day 7 by determining anastomotic bursting pressure (ABP), tissue hydroxyproline content, histopathological examination, malondialdehyde (MDA), and nitric oxide levels. RESULTS: Remote I/R injury resulted with significant impairment in anastomotic healing in terms of mean ABP (P = 0.004), hydroxyproline content (P = 0.002), histopathological healing score (P = 0.001), nitric oxide level (P = 0.010), and MDA levels (P = 0.0001) when compared with the control group, but remote IPC did not improve all above mentioned parameters (P = NS for all), except MDA level (P = 0.011) when compared with I/R group. PC alone impaired the ABP (P = 0.0001), but it did not significantly change the other parameters measured (P = NS). CONCLUSIONS: The results of this study showed that remote IPC did not prevent I/R-induced delaying in colonic anastomotic healing.     

肠缺血/再灌注损伤时中性粒细胞呼吸爆发活性的变化

目的:研究肠缺血/再灌注(I/R)时中性粒细胞(PMN)呼吸爆发活性的变化.方法:30只成年雄性Wistar大鼠,按照随机数字表法分为假手术,缺血45 min,缺血45 min再灌注60min、120min、360min等5组.阻断肠系膜上动脉血流45min后复流,复制I/R模型:假手术组只进行同样的手术操作但不阻断肠系膜上动脉血流.在各时间点分别取门静脉血测定白细胞计数,并分离PMN进行化学发光(CL)测定.结果:肠I/R损伤过程中,缺血组与假手术组比较,PMN的CL峰值无明显差异(P＞0.05),再灌注组PMN的CL峰值均明显升高(P＜0.01).肠缺血组白细胞数量较假手术组降低,再灌注后开始回升,再灌注360 min时白细胞计数最高.PMN化学发光峰值变化和血白细胞计数的变化趋势呈显著正相关(r=0.748,P＜0.05).结论:肠I/R损伤可激活循环中的PMN,使血中的PMN数量增加,PMN的呼吸爆发化学发光活性明显升高,可能是引起全身炎症反应和器官损害的因素之一.     

Selenium has a protective effect on ischemia/reperfusion injury in a rat ovary model: biochemical and histopathologic evaluation

Background/PurposeThe aim of the study was to evaluate the effects of selenium (Se) on ischemia/reperfusion (I/R) injury in rat ovaries.MethodsThirty-five female Sprague-Dawley rats were randomly divided into 5 groups (n = 7): sham (S), I/R1, I/R2, Se1, and Se2. In the I/R1 and Se1 groups, 4 hours of ischemia was followed by 6 hours of reperfusion, and in the I/R2 and Se2 groups, 4 hours of ischemia was followed by 12 hours of reperfusion. In the Se groups, 30 minutes before reperfusion, a single dose of 0.2 mg/kg Se was administered intraperitoneally. The ovarian tissue levels of malondialdehyde (MDA) and nitric oxide (NO), and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured biochemically. Tissue damage to ovarian tissue was scored by histopathologic examination.ResultsThe I/R groups had significantly higher MDA levels and lower CAT, SOD, and GPx activities than the sham group (P < .05). Although NO levels were significantly higher in the I/R1 group than in the sham group (P < .05), the NO levels in the I/R2 and sham groups were similar. Selenium pretreatment significantly lowered tissue MDA and NO levels and increased tissue SOD and GPx activities in the Se groups, compared with those in the I/R groups (P < .05). Catalase activities were significantly higher in the Se2 group than in the I/R2 group (P < .05). Catalase activities were higher in the Se1 group than in the I/R1 group, but the difference was not statistically significant. Treatment with Se significantly decreased the ovarian tissue damage scores in the Se2 group compared with those in the I/R2 group (P < .05).ConclusionSelenium is effective in preventing tissue damage induced by I/R in rat ovaries.     

Protective effects of pretreatment with Radix Paeoniae Rubra on acute lung injury induced by intestinal ischemia/reperfusion in rats

Objective： To investigate the effect of pretreatment with Radix Paeoniae Rubra （RPR） on acute lung injury induced by intestinal ischemia/reperfusion in rats and its protective mechanism.
Methods： Thirty-two Wistar rats were randomly divided into four groups： Sham-operation group, ischemla/ reperfusion group （I/R group ）, RPR-pretreatment group and hemin group. The model of intestinal ischemia/ reperfusion was established by clamping the superior mesenteric artery for 1 hour followed by 2-hour reperfusion. The effect of RPR on the expression of heme oxygenase-1 （HO-1） in lung tissues was detected by immunohistochemistry and morphometry computer image analysis. Arterial blood gas analysis, lung permeability index, malondialdehyde （MDA） and superoxide dismutase （SOD） contents in lungs were measured. The histological changes of lung tissue were observed under light microscope.
Resalts： The expression of HO-1 in RPR-pretreatment group and hemin group was obviously higher than that in sham-operation group and I/R group （ P 〈 0.01 ）. The level of MDA and lung permeability index in RPR-pretreatment and hemin group were significantly lower than those in I/R group （P〈0.01 or P〈0.05）, while the activity of SOD in RPR-pretreatment and hemin group was obviously higher than that in I/R group （P〈0.01）. Under light microscope, the pathologic changes induced by I/R were significantly attenuated by RPR.
Conclusion： Intestinal ischemia/reperfusion may result in acute lung injury and pretreatment with RPR injection can attenuate the injury. The protective effect of RPR on the acute lung injury is related to its property of inducing HO-1 expression and inhibiting lipid peroxidation.     

Protective effects of propofol against ischemia/reperfusion injury in rat kidneys

Aim: The purpose of this study was to investigate and compare the efficiency of propofol in the reduction of injury induced by free radicals in a rat model of renal ischemia/reperfusion (I/R). Method: Twenty-four Wistar rats were divided into four groups in our study. Rats in the sham group underwent laparotomy and were made to wait for 120 min without ischemia. Rats in the control group were given nothing with ischemia–reperfusion. Rats in the I/R groups were given propofol (25 mg/kg) and 10% intralipid (250 mg/kg) ip, respectively, 15 min before the ischemia for 60 min followed by reperfusion for 60 min. The kidney tissues of the rats were taken under anesthesia at the end of the reperfusion period. Evaluation of biochemical malondialdehyde (MDA), superoxide dismutase, and catalase activities and histopathological analysis were performed with these samples. Results: I/R significantly increased MDA levels (p < 0.05). Histopathological findings of the control group confirmed that there was renal impairment by tubular cell swelling, interstitial edema, medullary congestion, and tubular dilatation. MDA levels were lower in the propofol group compared to control group (p < 0.05). In the propofol group, the level of histopathological scores is significantly decreased than control and intralipid groups in ischemia–reperfusion. Conclusion: Our results demonstrate that I/R injury was significantly reduced in the presence of propofol. The protective effects of propofol may be due to their antioxidant properties. These results may indicate that propofol anesthesia protects against functional, biochemical, and morphological damage better than control in renal I/R injury.     

The effects of glucose-insulin-potassium solution and BN 52021 in intestinal ischemia-reperfusion injury

The objective of this study was to investigate effects of glucose-insulin-potassium (GIK) solution and BN 52021, a platelet-activating factor antagonist, on intestinal ischemia-reperfusion injury. Fifty male Sprague-Dawley rats (200-225 g) were divided into 5 groups each containing 10 rats; group SO, sham operation group; group I, mesenteric ischemia group (for 30 minutes); group R, ischemia plus reperfusion (for 60 minutes); group BR, ischemia-reperfusion plus BN 52021; group GR, ischemia-reperfusion plus GIK solution. Samples for malondialdehyde (MDA) and ileum (for mucosal injury score) were obtained. The mucosal injury scores of group R were significantly higher than those of group I (4 +/-0.20 and 3 +/-0.16, respectively, p<0.0001). The scores of groups BR and GR were significantly lower than those of group R (p<0.0001 and p<0.0001, respectively). When it was compared with the injuries in BR and GR groups, similar results were obtained in both groups (p=0.190). Mean MDA levels of group R were significantly higher than those of group I, BR and GR (131.33 +/-3.99 nmol/g, 93.74 +/-3.22 nmol/g, 104.81 +/-2.56 and 100.34 +/-5.30, respectively, p<0.0001). MDA levels of group BR and GR were significantly lower than those of group I (p<0.0001 and p=0.003, respectively). These observations suggest that treatment with GIK solution and BN 52021 before reperfusion and during reperfusion period may be useful in decreasing intestinal reperfusion injury.     

Ischemia/reperfusion-induced low reactivity of the rat superior mesenteric vascular bed is associated with expression of nitric oxide synthases

Our objective was to investigate the mRNA and protein expressions of eNOS and iNOS in the mesenteric vascular bed after ischemia and reperfusion of the rat superior mesenteric artery (SMA) and the role of nitric oxide (NO) in the response of the vascular bed to vasoconstrictors following reperfusion of the SMA. METHODS: Real-time polymerase chain reaction and immunohistochemistry were used to monitor the mRNA and protein expression of eNOS and iNOS after I/R challenge to the rat SMA. Ischemia was induced by clamping the SMA for 40 minutes, after which the flow was restored and the vessels were reperfused for 300 minutes. Blood samples were collected for assays of lactic dehydrogenase, tumor necrosis factor (TNF), hydroxyl radical, and NO. After ischemia/reperfusion, the vascular beds were separated for analysis of the expression of eNOS and iNOS. The SMA with its associated intestinal tissue was isolated and perfused in vitro with Tyrode's solution (N = 8) then challenged with phenylephrine. RESULTS: Reperfusion of the SMA induced an increase in blood concentrations of lactic dehydrogenase (P < .001; N = 8), hydroxyl radical (P < .05), TNF (P < .001), and NO (P < .05). ENOS and iNOS mRNA expression increased 1.3 +/- 0.1-fold and 19.6 +/- 3.5-fold, respectively when compared to the sham-operated group. Protein expression increased 1.9 +/- 0.4-fold and 12.6 +/- 3.1-fold, respectively, after reperfusion (N = 3) when compared with sham-treated rats. In vitro challenge showed that administration of phenylephrine (10(-8) approximately 10(-4) nmol) produced vasoconstriction in a dose-related manner. Maximum contractile responses to phenylephrine were attenuated in reperfused SMA. Addition of the NOS inhibitor N(G)-nitro-L-arginine (L-NNA, 10(-4) M) resulted in full recovery of the response to phenylephrine. CONCLUSIONS: Ischemia/reperfusion of the SMA results in a decrease in vascular reactivity of the mesenteric vessels that is dependent on NOS expression by the intestinal vascular bed.     

Effects of in vivo freezing and mannitol in intestinal ischaemia-reperfusion injury

PURPOSE: The main purpose of this study was to investigate whether in vivo freezing and mannitol administration can protect the small intestine against ischaemia-reperfusion (I-R) injury. METHODS: Fifty male Sprague-Dawley rats (200-225 g) were divided into 5 groups each containing 10 rats; group SO, sham operation group; group I, mesenteric ischaemia group; group R, ischaemia-reperfusion (I-R); group FR, I-R plus in vivo freezing; group MR, I-R plus mannitol treatment. Intestinal ischaemia for 30 min and reperfusion for 60 min were applied. Ileum specimens were obtained to determine the tissue levels of malondialdehyde (MDA) and histological changes. RESULTS: The mucosal injury scores of group R were significantly higher than those of the group I (P<0.0001). The mucosal injury scores in the groups FR and MR were significantly lower than the group R (P<0.0001 and P<0.0001, respectively). In the group FR, mucosal injury scores were not significantly different from those of group I (P=0.123). However, mucosal injury scores of group MR were significantly less when compared to those of group I (P=0.01). Mean MDA levels of group R were significantly higher than those of the group I (P<0.0001). Mean MDA levels of groups FR and MR were significantly lower than those of group R (P<0.0001 and P<0.0001, respectively). In addition, MDA levels of group FR were significantly higher than those of group MR (P<0.0001). CONCLUSION: In conclusion, these observations suggest that the in vivo freezing of SMA and the pre-treatment with mannitol before reperfusion period may be useful in preventing intestinal reperfusion injury.     

An animal model of ischemic priapism and the effects of melatonin on antioxidant enzymes and oxidative injury parameters in rat penis

This experimental study was designed to produce ischemia–reperfusion (I/R) injury in rat corpus cavernosum by inducing 1 h of priapism and investigating the effects of melatonin on the levels of oxidative injury parameters. Twenty-one adult male rats were randomly divided into three groups as follows; sham operated, control group (Group C): only penectomy was performed and blood (3 ml) drawn from vena cava inferior (VCI), ischemia and reperfusion group (Group I/R); priapism (1 h) + ½ h reperfusion + penectomy + blood from VCI, melatonin treatment group (Group I/R + M); priapism (1 h) + melatonin (½ h before reperfusion, 50 mg/kg, ip) + ½ h reperfusion + penectomy + blood from VCI. Priapism was induced with a vacuum erection device (cut tip of 2-cc syringe) and a rubber band was placed at the base of the erect penis. In two groups, excluding Group C, penectomies were performed after 1 h of ischemic priapism and ½ h reperfusion for biochemical analysis of superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and protein carbonyl (PC) in the tissues. In all groups, about 3 ml blood was drawn from VCI to study the same parameters in systemic circulation. The results were compared statistically using one-way analysis of variance (ANOVA). As a result, in biochemical examination of penile tissues, there were significant increase in SOD, CAT activities and MDA levels in I/R group in comparison with group C (P < 0.05). With melatonin treatment, these levels were decreased closer to control levels (P < 0.05). The changes in PC levels were insignificant in penile tissues of all groups (P > 0.05). Analysis of serum in all rats revealed that the activity of SOD and the levels of MDA, NO and PC were increased in I/R group when compared with control group but with multiple comparisons only the increases in SOD activity and NO level were significant (P < 0.05). Decrease in the activity of SOD and the levels of NO and PC were significant after melatonin administration in serum of all groups (P < 0.05). The results of this study showed that experimentally induced priapism caused oxidative injury in cavernosal tissues of rats, and treatment with melatonin alleviated these effects. From the result of this experimental study, it can be extrapolated that melatonin may be used as an antioxidant agent in the treatment of ischemic priapism in the future urology practice.     

15-F2t-isoprostane在大鼠肠缺血再灌注损伤中的作用

目的 评价异构前列腺素15-F2t-isoprostane在大鼠肠缺血再灌注损伤中的作用.方法 健康雄性SD大鼠32只,体重230 ～ 255 g,采用随机数字表法,将其随机分为4组(n=8):假手术组(S组)、肠缺血再灌注组(I/R组)、血栓烷A2(TXA2)受体拮抗剂SQ-29548组(SQ组)和二甲基亚砜组(DMSO组).采用阻断肠系膜上动脉60 min,再灌注120 min的方法制备肠缺血再灌注损伤模型.SQ组及DMSO组分别于夹闭肠系膜上动脉前30 min腹部皮下注射SQ-29548或二甲基亚砜2μmol/kg.于再灌注120 min时取肠段,观察肠粘膜形态学,并行Chiu评分,取肠粘膜组织,检测髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)、乳酸(LD)含量;采集动脉血样,检测血清二胺氧化酶( DAO)活性及15-F2t-isoprostane、内皮素-1(ET-1)和血栓烷B2(TXB2)浓度.结果 与S组比较,其余各组Chiu评分、DAO活性、15-F2t-isoprostane及TXB2浓度均升高(P＜0.05),SQ组LD和MDA含量、MPO和SOD活性及ET-1浓度差异无统计学意义(P＞0.05);与I/R组比较,SQ组Chiu评分、LD含量、DAO和MPO活性及ET-1浓度降低,SOD活性升高(P＜0.05).结论 15-F2t-isoprostane可通过激活TXA2受体,增加ET-1生成及促进中性粒细胞在肠粘膜聚集参与大鼠肠缺血再灌注损伤过程.     

Protective effects of resveratrol on spleen and ileum in rats subjected to ischemia-reperfusion

Resveratrol is as an antioxidant with free radical-scavenging activity and finds its clinical application in the prevention of postischemic tissue injury following solid organ transplantation. This study investigates the effect of Resveratrol on spleen and ileum tissues subjected to hepatic ischemia-reperfusion (I/R) in rats. Twenty-four rats were recruited in the study as follows: group A: I/R (n = 8), group B: I/R + Resveratrol (n = 8), and group C: sham operation (n = 8). After intraperitonealy pretreatment of eight rats with resveratrol (15 mg/kg/d) for 5 days, 16 rats were subjected to 45 minutes of hepatic ischemia followed by 30 minutes reperfusion period. Resveratrol was given 15 minutes prior to ischemia and just before the reperfusion in rats. After reperfusion period all rats were sacrificed. Spleen and ileum tissues were examined spectrophotometrically to measure malondialdehyde (MDA), glutathione (GSH), and total nitrite, nitrate as an end product of nitric oxide (NO) levels. Concerning the spleen, statistically significant decrease of GSH and increase of MDA and NO levels were found group A when compared to groups B and C (P = .040, P = .004, and P = .001 group A vs group B; P = .05, P = .003, and P = .001 group A vs group C, respectively). Parallel results were obtained in ileum. A statistically significant decrease in GSH and an increase in MDA and NO levels in group A in respect to group B and group C was obtained (P = .048, P = .034, and P = .001 group A vs group B; P = .004, P = .001, and P = .003 group A vs group C, respectively). The result of this study shows that resveratrol has a protective effect on spleen and ileal mitochondrial oxidative stress in rats subjected to I/R.     

Curcumin Nutrition for the Prevention of Mesenteric Ischemia-Reperfusion Injury: An Experimental Rodent Model

Background

Curcumin is an anti-oxidant molecule known to be a potent inhibitor of nuclear factor-κB (NF-κB). It has been shown to attenuate ischemia/reperfusion (I/R) injury in several organ systems. In this study, we sought to investigate the effects of curcumin on the prevention of superior mesenteric artery I/R injury in rats.

Methods

Wistar albino rats were randomly allocated to 3 groups: group I, sham operated (n = 10); group II, I/R injury only (n = 10); group III, curcumin-treated I/R cohort (n = 10). Group I animals underwent laparotomy without I/R injury. After group II animals underwent laparotomy, 60 minutes of superior mesenteric artery ligation were followed by 3 hours of reperfusion. In the curcumin group, 15 days before I/R, curcumin (40 mg/kg) was administered by gastric gavage. All animals were sacrificed at the end of reperfusion. Intestinal tissue samples were obtained to investigate intestinal mucosal injury; in addition we estimated levels of myeloperoxidase (MPO) activity, malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), interleukin (IL)-6, and tumor necrosis factor (TNF)-α.

Results

There were statistically significant decreases in GSH levels, along with an increase in intestinal mucosal injury scores, MPO activity, MDA levels, NO, IL-6, and TNF-α in group I when compared with groups II and III (P = .01). Curcumin treatment in group III produced a significant increase in GSH levels, as well as a decrease in intestinal mucosal injury scores, MPO activity, MDA, and NO levels when compared with group II (P < .05).

Conclusion

This study showed that curcumin treatment significantly attenuated reperfusion injury in a superior mesenteric artery I/R model in rats.     

Curcumin protects against ischemia/reperfusion injury in rat kidneys

OBJECTIVES: Renal ischemia followed by reperfusion leads to acute renal failure in both native kidneys and renal allograft. We investigated the effect of curcumin on ischemia-reperfusion (I/R) injury and the antioxidant effects of curcumin in rats. METHODS: Thirty rats were randomly divided into five experimental groups (control, sham, curcumin, I/R and I/R+curcumin, n=6 each). Curcumin was administered (200 mg kg(-1)) orally to curcumin and I/R+curcumin groups for 7 days. Then, the rats were subjected to bilateral renal ischemia for 45 min and followed by reperfusion for 24 h. All rats were killed and kidney function tests, serum and tissue nitric oxide (NO), protein carbonyl (PC), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were determined. Histopathological examinations were also performed. RESULTS: Curcumin significantly improved the urea and cystatin C levels in I/R+curcumin group compared to I/R group (p<0.05). Reduction of serum GSH-Px was significantly improved by curcumin (p<0.001), but SOD enzyme activity did not alter (p>0.05). Treatment with curcumin also resulted in significant reduction in serum and tissue MDA, NO and PC and for tissue that were increased by renal I/R injury (p<0.001 for serum and p<0.05 for tissue, respectively). In histological examination, the rats treated with curcumin had nearly normal morphology of the kidney. CONCLUSIONS: Based on our results, it can be concluded that curcumin protects the kidneys against I/R injury via its antioxidant effects.     

参麦注射液抗肝缺血再灌注损伤的研究

目的：研究参麦注射液对肝缺血再灌注损伤的保护作用。方法：将３７只成年雄性ＳＤ大鼠随机分成假手术对照组（ＳＯＣ）、缺血再灌注组（Ｉ／Ｒ）、缺血再灌注加参麦组（Ｉ／Ｒ＋ｓｈｅｎｍａｉ）。通过阻断大鼠肝门３０ｍｉｎ后再开放建立肝缺血再灌注损伤模型,在肝脏再灌注９０ｍｉｎ时测肝组织丙二醛（ＭＤＡ）、超氧化物歧化酶（ＳＯＤ）和测血ＡＬＴ、ＡＳＴ、ＬＤＨ,并取肝组织作光镜及电镜观察。结果：再灌注９０ｍｉｎ时Ｉ／Ｒ＋Ｓｈｅｎｍａｉ组的肝组织ＭＤＡ生成,ＳＯＤ消耗,血清ＡＬＴ、ＡＳＴ、ＬＤＨ升高值均少于Ｉ／Ｒ组（Ｐ＜０．０１）,且Ｉ／Ｒ＋Ｓｈｅｎｍａｉ组的肝细胞显微、超微结构损害的改变较Ｉ／Ｒ组轻。结论：参麦注射液能清除肝缺血再灌注过程中产生的氧自由基,对鼠肝缺血再灌注所致肝细胞的结构和功能损伤有保护作用     

Pyrrolidine Dithiocarbamate Reduces Lung Injury Caused by Mesenteric Ischemia/Reperfusion in a Rat Model

Background Pyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In this study, we aimed to study the effect of PDTC on lung reperfusion injury induced by superior mesenteric occlusion. Methods Male Wistar-albino rats randomized into three groups: (1) sham-operated control group (n = 12), laparotomy without I/R injury; (2) intestinal ischemia/reperfusion (I/R) group (n = 12), 60 min of ischemia by superior mesenteric occlusion followed by 2 h of reperfusion; and (3) I/R+PDTC-treated group (n = 12), 100 mg/kg injection of PDTC intravenously, 30 min after the commencement of reperfusion. Evans blue dye was injected to half of rats in all groups before the induction of I/R. We assessed the degree of pulmonary tissue injury biochemically by measuring malondialdehyde (MDA), glutathione (GSH), and nitric oxide (NO) levels, and histopathologically by establishing pulmonary neutrophil sequestration and acute lung injury scoring. Pulmonary edema was evaluated by Evans blue dye extravasation, as well as lung tissue wet/dry weight ratios. Results Pyrrolidine dithiocarbamate treatment significantly reduced the MDA and NO levels, and increased the GSH levels in the lung parenchyma, biochemically (p < 0.05), and atteneuated the pulmonary parenchymal damage, histopathologically (p < 0.05). However, pulmonary neutrophil sequestration was not affected by postischemic treatment with PDTC (p > 0.05). Pyrrolidine dithiocarbamate administration also significantly alleviated the formation of pulmonary edema, as evidenced by the decreased Evans blue dye extravasation and organ wet/dry weight ratios (p < 0.05). Conclusions This study showed that postischemic treatment with PDTC significantly attenuated the lung reperfusion injury. Further clinical studies are needed for better understanding of the specific mechanisms of PDTC protection against I/R-related organ injury and to clarify whether PDTC may be a useful therapeutic agent during particular operations where remote organ I/R injury occurs.     

The Effect of Dietary Ginger (Zingiber officinals Rosc) on Renal Ischemia/Reperfusion Injury in Rat Kidneys

Oxidative stress has been considered as one of the possible mechanisms of ischemia/ reperfusion (I/R) injury in the kidney. The aim of this study was to analyze the possible protective effect of dietary ginger (Zingiber officinals Rosc), a free radical scavenger, on renal I/R injury in rats. The protective effect of ginger against the damage inflicted by reactive oxygen species (ROS) during renal I/R was investigated in Wistar albino rats using histopathological and biochemical parameters. Thirty rats were randomly divided into five experimental groups (i.e., control, sham-operated, ginger, I/R, and I/R + ginger groups, n = 6 each). The ginger and I/R + ginger groups were fed on the test diet containing 5% ginger. The rats were subjected to bilateral renal ischemia followed by reperfusion in I/R and I/R + ginger groups. At the end of the reperfusion period, rats were sacrificed, and kidney function tests, serum and tissue oxidants and antioxidants, and renal morphology were evaluated. Serum urea, creatinine, and cystatin C (CYC) levels were significantly elevated in the ischemia group, but these levels remained unchanged in the ginger + I/R group compared to the I/R group. Reduction of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzyme activity was significantly improved by the treatment with ginger compared to I/R group. Administration of ginger resulted in significant reduction levels of tissue malondialdehyde (MDA), NO, protein carbonyl contents (PCC) in the ginger + I/R group compared with the I/R group. Ginger supplementation in the diet before I/R injury resulted in higher total antioxidant capacity (TAC) and lower total oxidant status (TOS) levels than I/R group. The ginger supplemented diet prior to I/R process demonstrated marked reduction of the histological features of renal injury. The findings imply that ROS play a causal role in I/R-induced renal injury, and ginger exerts renoprotective effects probably by the radical scavenging and antioxidant activities.