N-acetyl-L-cysteine mitigates aortic tone injury following liver ischemia-reperfusion

Liver ischemia and subsequent reperfusion (IR) are associated with secondary, remote organ reperfusion injury attributable to oxidative stress mediators. Because N-acetyl-L-cysteine (NAC) was effective in attenuating lung reperfusion injury, its properties on aortic dysfunction were tested. Rat isolated perfused aortic rings (n = 8/group) were evaluated during and after exposure to liver postischemia perfusate. Aortic response to phenylephrine under these conditions was also assessed in the presence or absence of increasing concentrations of NAC. Aortic rings incubated with postischemia perfusates exhibited abnormally protracted contraction. Their response to phenylephrine was reduced to 18 +/- 7% and 65 +/- 11% of controls during and after the exposure, respectively, and their subsequent relaxation was irregular. NAC 0.25 mM best attenuated the IR-induced aortic tone impairments, 0.12 mM affected it slightly, and IR-NAC 0.5 mM and IR-NAC 0.74 mM solutions dilated the rings proportionately, abolishing reactions to both IR solutions and phenylephrine. Xanthine oxidase activity and reduced glutathione (GSH) level in all IR ring tissues were inversely proportionate, but not directly so. Thus, liver IR impaired aortic tone and its response to phenylephrine, even after removal of toxic elements. NAC concentrations directly and inversely correlated with xanthine oxidase activity but not with GSH level. It preserved aortic functions dose-specifically, mainly by oxidant quenching.     

丙泊酚对大鼠肠缺血再灌注损伤时肝细胞凋亡及Caspase-3的影响

目的探讨丙泊酚对大鼠肠缺血再灌注损伤时肝细胞凋亡及Caspase-3的影响。方法成年健康Wistar大鼠42只,随机分为3组:实验对照组(C组,6只)、肠缺血再灌注组(IR组,18只)、丙泊酚干预组(P组,18只)。各组根据再灌注时间分为1,3,6h三个时相。通过夹闭肠系膜上动脉制作肠缺血再灌注损伤模型,实验结束后即刻取肝左叶做标本。用免疫组织化学法检测Caspase-3蛋白表达量,末端转移酶标记技术(TUNEL)法检测肝细胞凋亡指数(AI)。结果与C组比较,IR组和P组肝组织Caspase-3蛋白含量、AI均增加(P<0.05);与IR组比较,P组Caspase-3蛋白表达减少、AI减少(P<0.05)。结论丙泊酚可以下调大鼠肠缺血再灌注时Cas-pase-3蛋白表达,使肝细胞凋亡减轻,从而对肝损伤有一定的保护作用。     

雷帕霉素对肾缺血再灌注大鼠肝脏功能和超微结构的保护作用

目的 探讨雷帕霉素对肾缺血再灌注大鼠肝脏功能和细胞形态的保护作用。方法 24只雄性Wistar大鼠随机分为3组:假手术组、手术组、药物组。大鼠肾损伤模型为切除右肾,分离左肾动脉,阻断血流2h,再灌注4h,测定血清BUN、Scr含量、sALT、sAST活性,光镜下观察肝组织细胞形态学变化。结果 与假手术组比较,手术组血清BUN、Scr含量、sALT、sAST活性显著升高(P<0.05);与手术组比较,药物组血清BUN、Scr含量、sALT、sAST活性显著降低(P<0.05)。手术组:光镜下肝脏淤血,细胞脂肪变性及灶性坏死,炎症细胞侵润;药物组:病变较手术组明显减轻,仅肝中央静脉扩张、淤血。结论 雷帕霉素对肾缺血再灌注大鼠肝脏功能和超微结构均有明显的保护作用。     

Protection from renal ischemia reperfusion injury by an endothelin-A receptor antagonist BQ-123 in relation to nitric oxide production

The aim of this study was to investigate whether the protective effect of endothelin-A (ET(A)) receptor antagonist BQ-123 against renal ischemia reperfusion (I/R) injury is related to nitric oxide (NO) production. Sprague-Dawley rats were divided into six groups: control, I/R, N sup omega nitro-L-arginine methyl ester (L-NAME), BQ, BQ+L-NAME, BQ+L-NAME+L-Arg groups. After urethane anesthesia, 30min renal ischemia and 2h reperfusion were performed in all groups except control group. Mean arterial pressures (MAP) during reperfusion in all L-NAME-treated groups were higher than during pre-ischemia and ischemia, however, MAP at 60th and 120th minute of reperfusion in control and BQ groups were lower than during ischemia. MAP of L-NAME-treated groups were significantly higher than the other groups during reperfusion period. The I/R caused lipid peroxidation and protein oxidation, however, BQ-123 treatment prevented oxidant injury. The inhibition of NO production prevented effect of BQ-123 treatment. Also, BQ-123 treatment caused an increase in superoxide dismutase and catalase activities. Both BQ-123 and L-NAME treatments prevented high xanthine oxidase activity. BQ-123 prevented risen myeloperoxidase activity and L-NAME reversed this effect of BQ-123 just like the addition of L-arginine to the treatment altered the effect of L-NAME. The plasma BUN was affected as increasing manner from L-NAME treatments; on the other hand, plasma Cr and Na concentrations were affected as decreasing manner from BQ-123 treatments. ET(A) receptor antagonist BQ-123 may be revealed a protective agent against renal I/R injury with a possible secondary pathway via its antioxidant effects. We suggest that BQ-123 may mediate the protective effect via a NO-dependent mechanism.     

高压氧对大鼠肾缺血再灌注损伤的影响及其机制

目的:探讨高压氧对大鼠肾缺血再灌注损伤(IRI)的影响及其机制。方法:成年健康Wistar大鼠60只,随机分为4大组,正常对照组(n=6)、假手术组(n=18)、肾缺血再灌注组(IR组,n=18)和肾缺血再灌注+HBO治疗组(HBO治疗组,n=18)。后3组又按再灌注后1h、3h和5h各分为3个亚组,每个亚组大鼠6只。各组先切除右肾,取左肾研究。正常对照组切除右肾后立即切取左肾备用。假手术组不阻断左肾动脉,肾IR组和HBO治疗组则采用钳夹肾动脉法建立左肾缺血再灌注损伤模型。HBO治疗组:在肾缺血再灌注后0h、2h和4h时分别将大鼠置于动物实验用高压氧舱内治疗1h之后,治疗压力为2(Atmosphere absolute,ATA)(0.1MPa),舱内氧浓度在98%以上。各组分别于再灌注后1h、3h和5h时检测血中SCr、BUN、MDA和TNF-α的含量,并取左肾组织用于石蜡切片和HE染色、流式细胞术(Flow cytometry,FCM)行Amn-nexin V/PI双染法检测细胞凋亡以及电镜检查。结果:(1)在IR组,血中检测指标量显著高于同时点正常对照组和假手术组(P<0.05);在HBO治疗组,各指标在...     

Protection of rabbit kidney from ischemia/reperfusion injury by green tea polyphenol pretreatment

Reactive oxygen species (ROS) have been implicated in the pathogenesis of renal injury after ischemia/reperfusion (I/R). Recently, green tea polyphenols (GTP) have been found to protect the myocardium and liver against II/R injury. Less attention, however, has been paid to the protective effects of GTP with respect to the kidneys. This study was designed to determine whether GTP could protect renal cells from ischemic injury. The rabbits were divided into three groups of equal size: control (sham-operated), I/R + vehicle (normal saline) and I/R + GTP groups. Each group consisted of six rabbits. Animals underwent 30, 60, 90 and 120 min of ischemia, followed by 24 h of reperfusion, respectively. GTP (200 microg/kg) or the vehicle was administered 45 min prior to commencement of I/R. The results demonstrated that GTP administration resulted in a significant (P < 0.05) reduction of renal damage after 90 min of ischemia, as indicated by the decreased levels of creatinine and urea nitrogen in serum. These results were confirmed by histological examinations, which showed that GTP pretreatment inhibited necrosis and sloughing of the proximal tubules induced by I/R. Examinations also showed decreased necrotic areas in the medulla and decreased glomerular collapse in the I/R-injured rabbits. Moreover, the infiltration of CD8+ T cells was considerably decreased in GTP-treated kidneys. The results of this study suggest that GTP can reduce renal injury by preventing the oxidative stress dependent on I/R and may be used in renal transplantation as an antioxidant.     

Protective effects of melatonin and glucagon‐like peptide‐1 receptor agonist (liraglutide) on gastric ischaemia–reperfusion injury in high‐fat/sucrose‐fed rats

Ischaemia–reperfusion (I–R) injury is a serious pathology that is often encountered with thrombotic events, during surgery when blood vessels are cross‐clamped, and in organs for transplantation. Increased oxidative stress is the main pathology in I–R injury, as assessed in studies on the heart, kidney, and brain with little data available on gastric I–R (GI–R). Liraglutide is a GLP‐1 receptor agonist that has insulinotropic and weight reducing actions, and melatonin that has been much studied as a chronotropic hormone; have also studied as being anti‐oxidative stress agents. Herein, we aimed to explore the effects of liraglutide and melatonin on GI–R injury with high‐fat/sucrose diet. Rats were divided into six groups; two diet‐control, two melatonin‐ and two liraglutide‐pretreated groups. All rats were subjected to 30 minutes of gastric ischaemia followed by 1 hour of reperfusion. Gastric tissues were assessed for the percentage of DNA fragmentation, myeloperoxidase activity, total oxidant status, total antioxidant capacity, oxidative stress index, BMI and histopathological examination. We showed that high‐fat feeding for four weeks prior to GI–R significantly increased BMI, oxidative stress indices and decreased total antioxidant capacity, with a neutral effect on apoptosis compared to controls. Pretreatment with either melatonin (10 mg/kg per day orally) or liraglutide (25 μg/kg per day ip) reverses these effects. Furthermore, both drugs reduced weight only in HFS‐fed rats. Both liraglutide and melatonin have nearly similar protective effects on gastric I–R injury through decreasing the oxidative stress and apoptosis.     

乳化异氟醚后处理对兔在体心脏缺血/再灌注损伤的保护作用

目的观察乳化异氟醚后处理对兔在体心肌缺血/再灌注损伤的影响并探讨线粒体ATP敏感性钾通道(KATP)在其中的作用。方法76只♂新西兰白兔,建立心脏30min缺血/180min再灌注损伤模型,随机分为10组:缺血对照组(CON,n=8)、缺血后处理组(IPO,n=8)、1.0MAC吸入异氟醚后处理组(ISO,n=8)、1.0MAC乳化异氟醚后处理组(EPO,n=8)、脂肪乳组(INT,n=7)、Glibenclamide组(GLI,非选择性KATP通道阻滞剂,0.3mg.kg-1,n=7)、5-hydroxy-decanoate组(5-HD,线粒体KATP通道阻滞剂,5mg.kg-1,n=8)、0.3mg.kg-1GLI+1.0MAC EPO组(GLI+EPO,n=8)、5mg.kg-15-HD+1.0MAC EPO组(5-HD+EPO,n=7)、Dimethylsulfoxide组(DMSO,GLI的溶剂,n=7)。观察血流动力学指标,缺血区(AAR)重、梗死区(IS)重,心肌梗死面积(以IS/AAR表示),再灌注180min测定血清肌酸激酶(CK)、乳酸脱氢酶(LDH)活性。结果与CON组比较,IPO组、ISO组和EPO组IS/AAR及血清CK、LDH活性均明显降低(P<0.05);与EPO组比较,EPO+GLI组、EPO+5-HD组IS/AAR明显增加,血清CK、LDH活性明显升高(P<0.05)。结论乳化异氟醚可模拟缺血后处理减轻兔在体心肌缺血/再灌注损伤,这种心肌保护作用可能与线粒体KATP通道的激活有关。     

Short-term melatonin treatment improved diabetic nephropathy but did not affect hemorheological changes in diabetic rats

Increased oxidative stress and hemorheological disturbances may play very important roles in the development of microangiopathies in diabetes mellitus. This study was designed to determine the healing effect of melatonin on hemorheological parameters and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. Wistar male rats were divided into four groups as control, untreated-diabetic, melatonin-treated control and melatonin-treated diabetic rats. Diabetes was induced by injecting streptozotocin (45 mg/kg, i.p.). Fourteen weeks after inducement of diabetes, melatonin (10 mg/kg) was administered intraperitoneally for 5 days to the rats. Erythrocyte deformability and aggregation were measured by laser differaction analysis (LORCA). Diabetic nephropathy was assessed by histopathologic evaluation and TUNEL stain in the diabetic kidney. Decreased erythrocyte deformability and increased erythrocyte aggregation indices were determined in the diabetic group. Melatonin treatment did not improve these hemorheological abnormalities. However, renal injuries were diminished in the melatonin-treated diabetic group compared to the untreated diabetic group. Also, melatonin had an antiapoptotic effect on the diabetic kidney. It was concluded that i.p. administration of melatonin for 5 days improved renal injury in diabetic rats, probably by decreasing oxidative stress, but did not affect hemorheological changes.     

L-arginine protects from pringle manoeuvere of ischemia-reperfusion induced liver injury

Pringle described a new technique to reduce blood loss during liver surgery. Adult Wistar rats were subjected to 1 h of partial liver ischemia and followed by 3 h reperfusion. Eighteen Wistar rats were divided into sham-operated control group (I) (n=6), ischemia and reperfusion (I/R) group (II) (n=6), L-arginine treated group (100 mg/kg body weight/daily by oral route for 7 d before induced ischemia reperfusion maneuver) (III) (n=6). Ischemic and reperfusion hepatocellular injury occurred as indicated by increased-alanine transaminase (ALT), aspartate transaminase (AST). Pre-treatment with L-arginine significantly decreased serum-ALT, AST after 1 h ischemia followed by 3 h of reperfusion. Nitric oxide production, in hepatocytes was increased 2 fold and MDA levels significantly decreased by L-arginine treatment as compared to I/R rat. Histopathology and TEM studies showed markedly diminished hepatocellular injury in L-arginine pretreated rats during the hepatic I/R, which reached a level comparable to saline-treated rat of sham operated group. Thus, findings it may be concluded that L-arginine afforded significant protection from hepatobiliary function from I/R injury by nitric oxide production.     

家兔肠缺血-再灌注后各器官损伤变化的实验研究

目的探讨家兔肠缺血-再灌注引起各器官变化的特点。方法选取10只健康家兔,随机分为实验组（5只）与对照组（5只）,观察肝、肾、肺、心肌及胃肠的病理改变,检测血浆血浆丙二醛（MDA）、红细胞膜MDA、血浆黄嘌呤氧化酶（XOD）、血浆超氧化物歧化酶（SOD）的变化。结果实验组家兔的肝、肾、肺、心肌及胃肠均有较明显的病理改变。实验组血浆丙氨酸氨基转移酶（ALT）含量、肌酐含量、支气管肺泡灌洗液（BALF）蛋白含量、血浆和红细胞膜MDA及血浆XOD含量明显高于对照组（P〈0.05）,血浆SOD明显低于对照组（P〈0.05）。结论家兔肠缺血-再灌注可导致肝、肾、肺、心肌及胃肠损伤,氧自由基对各器官的破坏可能是病理变化的主要因素。     

非酒精性脂肪肝与2型糖尿病肾损伤关系的研究

目的探讨非酒精性脂肪肝（NAFLD）与2糖尿病肾损伤发生风险之间的关系。方法T2DM患者466例,分为T2DM伴NAFLD组（N组,n=266）及T2DM不伴NAFLD组（NN组,n=200）,测定24h尿微量白蛋白排泄率（UAER）,比较两组间肾脏损伤发生率。结果N组BMI、DBP、FPG、FCP、FINS、HbAlC、HOMA—IR、TC、TG、ALT、UAER高于NN组（P〈0．05）;N组的肾损伤发生率高于NN组（P〈0．05）;Logistic回归分析显示,NAFLD是2糖尿病肾损伤的独立危险因素（P〈0．05）。结论N组2糖尿病肾损伤的发生率高于NN组,NAFLD是2糖尿病肾损伤的独立危险因素。     

褪黑素和己酮可可碱减缓肝缺血再灌注损伤的实验研究

目的　探讨褪黑素 (MT)和己酮可可碱 (PTX)对肝脏缺血再灌注损伤的保护作用。方法　 12 8只SD大鼠随机分为4组 :对照组、MT组、PTX组及MT与PTX联合组。所有大鼠均在阻断第一肝门 35min后恢复入肝血流 ,其间行肝左外叶切除。测定缺血前、后及再灌注时的血清ALT、LDH、TNF α、肝组织MDA、SOD及ET 1的含量 ;并观察大鼠一周的生存率。结果　①肝功能 :各组ALT和LDH值均明显升高 ,但用药组的上升幅度明显低于对照组 ,且以联合用药组的降低更为明显 ;②ET 1:各组ET 1值均明显增加 ,但用药组的升高幅度明显低于对照组 ;③MT疗效 :各组MDA及SOD均明显增加 ,但MT使用组 (含MT组和联合组 )的升高幅度较其它组别明显降低 ;④PTX疗效 :各组TNF α值均明显升高 ,但PTX使用组 (含PTX组及联合组 )的升高幅度明显低于其它组别 ,且生存率较其它组别明显增加。结论　①MT可降低脂质过氧化程度 ,但对提高生存率无明显作用 ;②PTX可减轻炎性细胞因子释放、提高生存率 ;③联合应用MT和PTX可显著减轻肝功能损害 ,提高大鼠生存率。     

右美托咪啶对肾脏缺血再灌注损伤大鼠肾组织血红素氧合酶-1表达的影响

目的评价右美托咪啶对肾脏缺血再灌注损伤大鼠肾组织血红素氧合酶-1表达的影响。方法健康Wistar大鼠36只,雌雄不限,体重300~350g,随机分为3组:假手术组(S组)、肾脏缺血再灌注组(IR组)和右美托咪啶组(D组),各12只。采用动脉压夹夹闭双侧肾动脉60min、恢复灌注4h建立大鼠肾脏缺血再灌注模型。D组于夹闭双侧肾动脉前10min尾静脉注射右美托咪啶3μg/kg;IR组于夹闭双侧肾动脉前10min尾静脉注射等容量生理盐水;S组不夹闭双侧肾动脉,分离肾动脉后尾静脉注射等容量生理盐水。术后再灌注4h时处死大鼠取肾组织,采用PCR技术检测血红素氧合酶-1mRNA的表达,Westernblot法测定血红素氧合酶-1(HO-1)蛋白水平,光镜下观察肾组织病理学结果。结果与S组比较,IR组和D组肾组织血红素氧合酶-1mRNA和HO-1蛋白的表达上调(P<0.05);与IR组比较,D组肾组织血红素氧合酶-1mRNA和HO-1蛋白的表达上调(P<0.05),肾组织病理学损伤减轻。结论右美托咪啶减轻大鼠肾脏缺血再灌注损伤与其上调肾组织血红素氧合酶-1的表达有关。     

Effects of N-acetyl-L-cysteine on renal haemodynamics and function in early ischaemia-reperfusion injury in rats

1. Renal ischaemia-reperfusion (IR) severely compromises kidney function and has been shown to cause persistent abnormalities in intrarenal blood flow. The aim of the present study was to examine whether N-acetyl-L-cysteine (NAC), a thiol-containing anti-oxidant, improves renal haemodynamics and function during early reperfusion in rats subjected to renal IR. 2. Male Sprague-Dawley rats were divided into groups receiving either isotonic saline (IR-Saline; n = 8) or NAC (IR-NAC; n = 8) prior to (200 mg/kg, i.p., 24 and 12 h before acute experimentation) and during acute renal clearance experiments (bolus 150 mg/kg followed by a continuous infusion of 43 mg/kg per h, i.v.). During acute experimentation, thiobutabarbital-anaesthetized rats were subjected to a right-sided nephrectomy, followed by left kidney IR (40 min renal artery occlusion). Left kidney function and blood flow and intrarenal cortical and outer medullary perfusion measured by laser-Doppler flowmetry was analysed at baseline, during ischaemia and for 80 min of reperfusion. 3. Renal IR produced an approximate 85% reduction in glomerular filtration rate (GFR) and a pronounced increase in fractional urinary sodium excretion, throughout reperfusion, with no statistically significant differences between groups. 4. During reperfusion, total renal blood flow and cortical and outer medullary perfusion rapidly returned to levels not significantly different from baseline in both groups. The relative increase in renal vascular resistance in response to IR was more pronounced in NAC-treated rats compared with saline-treated animals (P < 0.05). 5. In conclusion, treatment with NAC did not improve kidney function during the first 80 min after renal IR. In addition, the marked reduction in GFR following reperfusion was not associated with any detectable abnormalities in intrarenal perfusion.     

Naloxone Postconditioning Alleviates Rat Myocardial Ischemia Reperfusion Injury by Inhibiting JNK Activity

To investigate the alteration of c-Jun N-terminal kinase (JNK) activity after myocardial ischemia reperfusion injury (MIRI) and further explore the effect of naloxone postconditioning on MIRI. Forty male Sprague Dawley rats were randomly divided into five groups: sham operation (sham, n=8); ischemia reperfusion (IR, n=8); IR+naloxone 0.5 mg/kg (Nal L, n=8); IR+naloxone 1.0 mg/kg (Nal M, n=8); IR+naloxone 2.0 mg/kg (Nal H, n=8). Pathological changes of myocardial tissue were visualized by HE staining. The expression of p-JNK, and the apoptosis of cardiomyocytes were investigated with Western blotting and the TUNEL assay, respectively. Irregular arrangement and aberrant structure of myocardial fibers, cardiomyocytes with granular or vacuolar degeneration, and inflammatory cells infiltrating the myocardial interstitial regions characterized MIRI in the IR group. Signs of myocardial injury and inflammatory infiltration were less prominent in the Nal-treated groups. The expression of p-JNK in the sham group and in all Nal-treated groups was significantly lower than that in the IR group (p<0.01). The apoptosis index of cardiomyocytes in the IR group was significantly higher than in the sham group (p< 0.01). The apoptosis indices of cardiomyocytes in all Nal-treated groups were significantly reduced to 55.4%, 26.2%, and 27.6%, respectively, of the IR group (p< 0.01). This study revealed that Naloxone postconditioning before reperfusion inhibits p-JNK expression and decreases cell apoptosis, thus alleviating MIRI.     

Melatonin reduces urinary excretion of N-acetyl-beta-D-glucosaminidase, albumin and renal oxidative markers in diabetic rats

1. Increased oxidative stress has an important role in the pathogenesis of diabetic nephropathy. The aim of the present study was to evaluate diabetic nephropathy by determining markers of oxidative stress and the urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), albumin and to investigate the possible protective effects of in vivo melatonin on renal tubular oxidative damage in diabetic rats. 2. Twenty-six rats were randomly divided into three groups: (i) group I, control, non-diabetic rats (n = 9); (ii) group II, untreated diabetic rats (n = 8); and (iii) group III, melatonin-treated diabetic rats (n = 9). In groups II and III, diabetes developed 3 days after administration of a single dose of streptozotocin (35 mg/kg, i.p.). Thereafter, whereas the rats in group II received no treatment, rats in group III began to receive 10 mg/kg per day, i.p., melatonin for 8 weeks. Malondialdehyde (MDA), an index of lipid peroxidation, NAG and microalbumin in the urine, markers of renal tubular damage, were the parameters used for oxidative stress-induced renal injury. Superoxide dismutase (SOD), xanthine oxidase (XO) and glutathione peroxidase (GSH-Px) activities were determined to evaluate changes in the anti-oxidant status of kidney tissue. 3. In untreated diabetic rats, urinary NAG, albumin and renal MDA levels were markedly increased compared with control rats (P < 0.0001). However, these parameters were reduced in diabetic rats by melatonin treatment (P < 0.0001). Urinary excretion of NAG was positively correlated with the microalbuminuria and renal MDA levels (r = 0.8; P < 0.0001). The SOD and XO activities in the untreated diabetic group were found to be significantly higher than those of the control group (P < 0.0001). Superoxide dismutase and XO activities decreased in melatonin-treated rats compared with untreated diabetic rats (P < 0.002 and P < 0.023, respectively). However, the decrease did reach levels seen in control rats. There were no significant differences in GSH-Px activity between the three groups. 4. Therefore, on the basis of these data, we suggest that urinary NAG, albumin excretion, XO activity and MDA levels are more valuable parameters showing the degree of renal tubular injury than classical markers of oxidative stress, including SOD and GSH-Px, in diabetic rat kidneys. Melatonin has an ameliorating effect on oxidative stress-induced renal tubular damage via its anti-oxidant properties. Thus, it may be suggested that urinary NAG excretion and microalbuminuria may be important markers showing the degree of renal changes and the success of long-term treatment of renal impairment with melatonin.     

The protective effect of prophylactic ozone administration against retinal ischemia-reperfusion injury

Introduction: Retinal ischemia-reperfusion (IR) injury is associated with many ocular diseases. Retinal IR injury leads to the death of retinal ganglion cells (RGCs), loss of retinal function and ultimately vision loss. The aim of this study was to show the protective effects of prophylactic ozone administration against retinal IR injury.

Materials and methods: A sham group (S) (n?=?7) was administered physiological saline (PS) intraperitoneally (i.p.) for 7 d. An ischemia reperfusion (IR) group (n?=?7) was subjected to retinal ischemia followed by reperfusion for 2?h. An ozone group (O) (n?=?7) was administered 1?mg/kg of ozone i.p. for 7 d. In the ozone?+?IR (O?+?IR) group (n?=?7), 1?mg/kg of ozone was administered i.p. for 7 d before the IR procedure and at 8 d, the IR injury was created (as in IR group). The rats were anesthetized after second hour of reperfusion and their intracardiac blood was drawn completely and they were sacrificed. Blood samples were sent to a laboratory for analysis of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), total oxidant score (TOS) and total antioxidant capacity (TAC). The degree of retinal injury was evaluated according to changes in retinal cells and necrotic and apoptotic cells using the TUNEL method. Data were evaluated statistically with the Kruskal-Wallis test.

Results: The number of RGCs and the inner retinal thickness were significantly decreased after ischemia, and treatment with ozone significantly inhibited retinal ischemic injury. In the IR group, the degree of retinal injury was found to be the highest. In the O?+?IR group, retinal injury was found to be decreased in comparison to the IR group. In the ozone group without retinal IR injury, the retinal injury score was the lowest. The differences in the antioxidant parameters SOD, GSH-Px and TAC were increased in the ozone group and the lowest in the IR group. The oxidant parameters MDA and TOS were found to be the highest in the IR group and decreased in the ozone group.

Discussion: IR injury is also positively correlated with the degree of early apoptosis. This study demonstrated that ozone can attenuate subsequent ischemic damage in the rat retina through triggering the increase of the antioxidant capacity.     

Protective effects of naringin and trimetazidine on remote effect of acute renal injury on oxidative stress and myocardial injury through Nrf-2 regulation

BackgroundIschemia/reperfusion (I/R) is the predominant cause of acute renal failure (ARF), which damages the remote organs, especially the heart, and subsequently leads to death. The aim of the current study was to examine the effects of naringin (NAR), trimetazidine (TMZ), or their combination on the Nrf-2 expression in the kidney tissue, and myocardial injury in the renal IR injury in rats.MethodsForty male Sprague-Dawley rats were randomly separated into five groups as follows: sham, IR injury, TMZ (5 mg/kg, intravenously), NAR (100 mg/kg), and their combination. Renal I/R injury and ischemia were induced by using clamps for 45 min, and after 4 h reperfusion, respectively. Then, the Nrf-2 expression in the kidney, antioxidant activity (CAT, SOD, and GPx), total antioxidant capacity (TAC), oxidative stress, electrocardiogram (ECG) parameters, and biochemical markers were examined.ResultsRenal IR injury significantly reduced the Nrf-2 expression, superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) enzymes’ activities and TAC. Moreover, Malondialdehyde (MDA) level in kidney and heart tissues, plasma creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH) activity were increased, and ECG parameters were significantly distributed; however, NAR, TMZ, or their combination improved these changes, in comparison with the renal IR injury in rats.ConclusionNAR, TMZ, or their combination could attenuate the Nrf-2 expression in the kidney tissue, following the renal IR injury through inhibition of lipid peroxidase, and enhancement of antioxidant activity.