Changes in protein and mRNA expression levels of claudin family after mucosal lesion by intestinal ischemia/reperfusion

Ischemia/reperfusion (I/R) injury of the intestine is the leading cause of organ dysfunction after restoration of blood flow after diverse events, including shock and intestinal transplantation. I/R injury must be overcome for successful small intestinal transplantation. Tight junctions (TJ) are the most apical component of the intercellular junctional complex in epithelial cells; they establish cell polarity and functioning as major determinants of epithelial barrier function. Among the proteins that comprise TJ, the claudin family is thought to play a crucial role in homeostasis in multicellular organisms. Therefore, the aim of this study was to examine the changes in function of TJ and behavior of the claudin family during intestinal I/R. Wistar/ST rats underwent intestinal ischemia by using the spring scale and surgical suture for 1h, followed by 24h of reperfusion. We examined the changes in area under the blood concentration curve (AUC) after oral administration of FD-4, which is a paracellular marker, and claudin-1, -2, -4, and -7 mRNA and protein expression levels in ileum. The structure of ileal mucosa was partly damaged and its function was diminished by intestinal I/R until 3h after reperfusion, but were almost recovered 24h after reperfusion. However, a time difference was shown between the recoveries of mucosal structure and function. Furthermore, a difference in the expression among various kinds of claudin was found. It was suggested that claudin-4 and multi-PDZ domain protein, which is a scaffolding protein, regulate intestinal paracellular permeability during intestinal I/R. Moreover, the changes in the expression level of claudin-2 were unique.     

无创性延迟肢体缺血预适应对抗大鼠脑缺血再灌注损伤的内皮机制

目的:研究无创性延迟肢体缺血预适应(noninvasive delayed limb ischemic preconditioning,NDLIP)对脑缺血再灌注大鼠内皮细胞分泌功能的影响并探讨其作用机制。方法:健康雄性Wistar大鼠随机分为假手术组(Sham)、脑缺血再灌损伤(ischemia-reperfusion injury, I/R)组、早期脑缺血预适应(early cerebral ischemic preconditioning,ECIP)组和NDLIP组,建立大鼠脑缺血再灌注模型,实施1 h缺血/24 h再灌注,ECIP组于缺血前左侧颈总动脉行3次5 min缺血/5 min再灌注,NDLIP组于缺血前3 d每天左后肢实施3次5 min缺血/5 min再灌注。TTC染色法测定脑梗死面积,分别在缺血前及再灌注24 h后测定血清内皮素(endothelin, ET-1)、一氧化氮(nitric oxide, NO)的含量及组织纤溶酶原激活物(tissue plasminogen activator, t-PA)、纤溶酶原激活物抑制剂(plasminogen activator inhibitor, PAI-1)的活力。结果:缺血前,与I/R组比较,ECIP组和NDLIP组血清NO浓度升高(P<0.05),ET-1/NO比值降低(P<0.05),再灌注后,与I/R组比较,ECIP组和NDLIP组梗死范围显著减小,血清ET-1降低(P<0.01),NO增加(P<0.01),ET-1/NO比值降低(P<0.05),t-PA活力升高(P<0.01),PAI-1活力降低(P<0.01)。结论:NDLIP可能是通过调整内皮细胞分泌收缩与舒张、促凝与抗凝物质的平衡,抵抗脑缺血再灌注损伤的作用,其保护程度与ECIP相当。     

Changes in the localization of ileal P-glycoprotein induced by intestinal ischemia/reperfusion

P-glycoprotein is one of the most important transporters in the ATP binding cassette transporter. Moreover, it is well known that the efficacy of immunosuppressants, which are used after organ transplantation, is controlled by P-glycoprotein (P-gp). We investigated how ischemia/reperfusion (I/R), which occurs after transplantation, influences the expression level and function of P-gp. To clarify the influence of intestinal I/R on the localization of P-gp, an intestinal ischemia model was produced using a spring scale and surgical sutures for 1 h, followed by reperfusion for 24 h. The expression levels of mRNA and protein of P-gp were examined. The protein expression levels of P-gp in ileal homogenate and the brush border membrane (BBM) were significantly decreased until 3 h after reperfusion. While the protein expression level of P-gp in homogenate showed a tendency to increase, that in the BBM continued to significantly decrease until 24 h after reperfusion. In contrast, the protein expression level of P-gp in the basolateral membrane (BLM) increased significantly until 24 h after reperfusion. While no significant change in multidrug resistance (mdr)-1a mRNA was found, the levels of mdr-1b and mdr-2 significantly increased during intestinal I/R. In addition, the levels of inflammatory cytokines mRNA and nitric oxide (NO) also significantly increased. It was shown that mdr-1b and mdr-2 mRNA strongly participate in the recovery of P-gp protein level after intestinal I/R. We detected the abnormal localization of P-gp in the ileal membrane during intestinal I/R, suggesting NO and/or inflammatory cytokines participate in the abnormal localization of P-gp.     

Caffeic acid phenethyl ester (CAPE) protects rat skeletal muscle against ischemia-reperfusion-induced oxidative stress

Oxygen-derived free radicals have been implicated in the pathogenesis of skeletal muscle injury after ischemia-reperfusion. Caffeic acid phenethyl ester, an active component of propolis extract, exhibits antioxidant properties. The aim of this study was to assess the effects of caffeic acid phenethyl ester (CAPE) and alpha-tocopherol (vit E) on ischemia/reperfusion (I/R) injury in a rat hind limb ischemia/reperfusion model. For this purpose, ischemia was induced in anesthetized rats by unilateral (right) femoral artery clipping for 2 h followed by 2 h of reperfusion. Four groups were studied: sham, I/R, I/R+CAPE and I/R+vit E. Drugs were administered intraperitoneally after 1 h of ischemia and I/R rats received saline vehicle. After 2 h of reperfusion, venous blood was sampled and the right gastrocnemius muscle was harvested. Plasma and tissue were assayed for malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO) metabolites. Tissue was also assayed for catalase (CAT) activity. Both tissue and plasma NO levels, MDA levels, SOD activities was significantly increased in I/R groups compared to control groups. The two treated groups showed decreased MDA and NO in both muscle and plasma compared to the I/R group. No differences were noted in muscle tissue SOD in three I/R groups, but SOD activity were increased in the plasma of I/R+CAPE and I/R+vit E groups compared with I/R group. Whereas tissue CAT activity was not changed among groups. Our results indicate that CAPE has antioxidant properties similar to those of vit E in this model and may attenuate the harmful effects of hind limb I/R in skeletal muscle.     

Effects of nitric oxide on mucosal barrier dysfunction during early phase of intestinal ischemia/reperfusion

Ischemia/reperfusion (I/R) injury must be overcome for successful small intestinal transplantation. During intestinal I/R, the expression level of nitric oxide (NO) is increased, and vermiculation of the mucosal tract is induced by NO. Although NO has many beneficial effects on intestinal I/R injury, its role in intestinal I/R injury is controversial. Therefore, in the present study, we examined changes in the tight junctions (TJ) and P-glycoprotein (P-gp) by aminoguanidine (AG), which can be considered a selective inducible NO synthase inhibitor during intestinal I/R, to clarify the effect of NO on mucosal barrier dysfunction during intestinal I/R. A mucosal lesion was induced by intestinal I/R. The protein expression levels of the claudin family organizing TJ and P-gp, were decreased, and their functions were also decreased. Through the inhibition of NO generation by AG in the above mucosal lesion, TJ and P-gp dysfunction was significantly inhibited. NO participated in opening TJ and decreasing P-gp function and expression induced during intestinal I/R. Therefore, it is important to consider the level of NO generation in the ileal mucosa in drug therapy for intestinal I/R injury.     

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.     

大鼠高血糖－局灶性脑缺血再灌注损伤模型建立的初步研究

目的:建立快速、稳定的大鼠高血糖-局灶性脑缺血再灌注损伤(I/R)模型,探讨将其用于脑缺血再灌注损伤相关研究的可行性.方法:24只大鼠随机等分为4组,分别为正常血糖和高血糖下假手术组(NG-sham,HG-sham),正常血糖和高血糖下脑缺血再灌注损伤组(NG-FCIR, HG-FCIR).术前1 h腹腔注射10%右旋葡萄糖制备高血糖大鼠;采用线栓法阻断大脑中动脉(MCAO)建立I/R模型,脑缺血1 h再灌注3 h.测定各组注射葡萄糖前、缺血开始和再灌注3 h后的血糖;TTC染色比较各组脑组织水肿程度和脑梗死面积;比较各组脑组织乳酸脱氢酶活性、总NOS和iNOS、SOD酶活性,以及NO、MDA含量.结果:与对照组相比,缺血前注射葡萄糖的各组血糖明显升高(P<0.01),并且持续至再灌注3h(P<0.01).与NG-FCIR组相比,HG-FCIR组的脑组织水肿程度增加、脑梗死面积明显增大(P<0.05),脑组织乳酸脱氢酶、总NOS、iNOS活性增加(P<0.05),SOD酶活性明显降低(P<0.05),NO、MDA含量明显增多(P<0.05).结论:术前1 h腹腔注射右旋葡萄糖(2g·kg-1)可诱导大鼠高血糖状态,加速、加重MCAO引起的局灶性脑缺血再灌注损伤.采用高血糖模型,缺血1 h、再灌注3 h时即可用于ROS、NO等相关的药物疗效或机制研究,可显著缩短观察时间.     

Propofol attenuation of renal ischemia/reperfusion injury involves heme oxygenase-1

Aim： To examine the protective effect of propofol in renal ischemia/reperfusion （I/R） injury and the role of heme oxygenase-1 （HO-1） in this process. Methods： Sprague-Dawley rats were randomly divided into 3 groups： （i） sham-operated group; （ii） I/R group; and （iii） propofol group. Bilateral renal warm ischemia for 45 min was performed. After 2, 6, and 24 h reperfusion, blood samples and kidneys were collected for assessment of renal injury, and HO-1 expressions were analyzed by immunohistochemical analysis, RT-PCR and Western blotting. Results： Blood urea nitrogen and serum creatinine levels in the propofol group were significantly lower than that in the I/R group at 24 h after reperfusion. The mean histological score by Paller＇s standard showed that propofol significantly attenuated renal I/R injury after 6 h reperfusion. Propofol increased HO-1 mRNA and protein levels 2 h after reperfusion, whereas HO-1 expressions were present at exceedingly low levels in the I/R group and the sham-operated group at same time point. Propofol also markedly increased HO-1 mRNA and protein levels than I/R at 6 and 24 h after reperfusion. Conclusion： These results suggest that propofol mitigates renal I/R injury in rats. This protection may be partly through the induction of the HO- 1 expression.     

RETRACTED: Effect of trimetazidine on renal ischemia/reperfusion injury in rats

There is increasing evidence to suggest that toxic oxygen radicals play a role in the pathogenesis of ischemia/reperfusion (I/R) injury in the kidney. This study was designed to investigate the effects of trimetazidine, in I/R induced renal failure in rats. The protective effect of trimetazidine (Tmz) against the damage inflicted by reactive oxygen species (ROS) during renal I/R was investigated in Sprague-Dawley rats using histopathological and biochemical parameters. In one set of experiments animals were unilaterally nephrectomized, and subjected to 45 min of left renal pedicle occlusion and in another set both the renal pedicles were occluded for 45 min followed by 24 h of reperfusion. Trimetazidine (3 mg kg(-1), i.p.) was administered 30 min prior to ischemia and repeated 12 h after the first dose. At the end of the reperfusion period, rats were sacrificed. Thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) levels, glutathione reductase (GR) catalase (CAT), and superoxide dismutase (SOD) activities were determined in renal tissue. Serum creatinine and blood urea nitrogen (BUN) concentrations were measured for the evaluation of renal function. Ischemic control animals demonstrated severe deterioration of renal function, renal morphology and a significant renal oxidative stress. Pretreatment of animals with trimetazidine markedly attenuated renal dysfunction, morphological alterations, reduced elevated TBARS levels and restored the depleted renal antioxidant enzymes. The findings imply that ROS play a causal role in I/R induced renal injury and trimetazidine exert renoprotective effects probably by the radical scavenging and antioxidant activities.     

朝鲜当归提取物对小鼠脑缺血-再灌注损伤神经的保护作用及其机制

目的探讨朝鲜当归提取物对小鼠脑缺血-再灌注(I/R)损伤影响及其机制。方法雄性C57BL/6小鼠随机分为6组,分别为假手术组、模型对照组和朝鲜当归(10,25,50,100 mg·kg^-1)组(n=9)。I/R小鼠采用大脑中动脉阻塞(MCAO)方法使小鼠短暂缺血90 min,再灌注24 h。应用2,3,5-氯化三苯基四氮唑染色法和伊文思兰染色评价大鼠脑梗死体积和血-脑屏障通透性变化;利用蛋白免疫印迹(Western blotting)方法检测血管生成诱导蛋白如血管生成素1(Ang-1)和血管内皮生长因子(VEGF)表达,紧密连接蛋白如ZO-1和Occludin表达;同时检测磷脂酰肌醇3-激酶(PI3K)/Akt磷酸化表达。结果朝鲜当归提取物可显著缩小I/R小鼠脑梗死体积(P<0.05),降低I/R小鼠血-脑屏障通透性(P<0.05),还可激活PI3K/Akt通路,增加Ang-1、VEGF、ZO-1和Occludin蛋白表达(P<0.05)。结论朝鲜当归可能通过降低血脑屏障通透性及促进血管生成在小鼠I/R损伤中发挥神经保护作用。     

褪黑素对肠缺血再灌注损伤保护作用的临床研究

目的 研究褪黑素对肠缺血再灌注损伤(IIRI)的保护作用.方法 研究对象随机分为缺血再灌注A组,生理盐水处理B组,地塞米松治疗C组,褪黑素治疗D组,每组20例.手术解除肠缺血前后10min分别静脉注射生理盐水10ml、地塞米松20mg和褪黑素20μg,手术结束后1h内采外周静脉血,用MDA、SOD试剂盒测定血浆MDA浓度和SOD活性.用NO试剂盒和酶学分光光度法测定血浆NO2-/NO3-水平和血浆D-乳酸水平.观察处理后各组肠管颜色完全恢复时间和术后肛门排气时间.结果 褪黑素治疗组与生理盐水处理组和地塞米松治疗组比较,血浆SOD活性明显上升(P＜0.01),MDA浓度降低(P＜0.05),血浆中NO2-/NO3-浓度上升(P＜0.05),D-乳酸明显降低(P＜0.01),各组肠管颜色完全恢复时间和术后肛门排气时间均有缩短(P＜0.05).结论 褪黑素对肠缺血再灌注损伤有较好保护作用,其机制可能是通过清除氧自由基,防止脂质过氧化和保护肠黏膜机械屏障.     

Endothelin receptor blockers protect against ischemia/reperfusion impairment of gastrointestinal motility in rats

Intestinal ischemia/reperfusion (I/R) injury remains associated with high morbidity and mortality. The protective efficacy of the following endothelin (ET) receptor blockers: BQ-123 (ET(A) receptor), BQ-788 (ET(B)); tezosentan (dual ET blocker) was tested against the inhibition of gastrointestinal (GI) motility induced by intestinal I/R. Intestinal Evans blue transit was measured in untreated (UN) rats and animals subjected to skin incision (SI), I/R (1h superior mesenteric artery clamping followed by 2-24h reperfusion) or sham operation (SO). Surgical procedures were conducted under diethyl ether anesthesia. Anesthesia and SI did not affect the GI transit compared to UN rats. In contrast both SO and I/R significantly reduced GI motility, the latter evident at 2-24h of reperfusion. Tezosentan (1-10 mg/kg), BQ-123 and BQ-788 (0.1-1 mg/kg) protected against I/R-induced inhibition of intestinal motility in a time- and dose-dependent manner at the early and late stages of reperfusion. Furthermore tezosentan alleviated the I/R-induced decrease in the contractile response of the longitudinal jejunal smooth muscle strips to carbachol in vitro. The serum ET(1-21) level was increased at 2h but not 24h of reperfusion compared to SO animals and ET(1-21) was higher in tezosentan pretreated rats.     

Protective effect of nitric oxide on ischemia/reperfusion-induced renal injury and endothelin-1 overproduction

To elucidate the role of nitric oxide (NO) in the pathogenesis of ischemic acute renal failure, we examined the effects of (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409) and N(G)-nitro-L-arginine methyl ester (L-NAME) as a NO donor and a non-selective NO synthase inhibitor on ischemia/reperfusion-induced renal injury and renal endothelin-1 content. Ischemic acute renal failure was induced by occlusion of the left renal artery and vein for 45 min followed by reperfusion, 2 weeks after contralateral nephrectomy. At 24 h after reperfusion, renal function in untreated acute renal failure rats markedly decreased and histological examination revealed severe renal damage. In addition, increases in renal endothelin-1 contents were evident in the acute renal failure rats at 2, 6, and 24 h after reperfusion, respectively. Pretreatment with FK409 (1 or 3 mg/kg, i.v.) attenuated ischemia/reperfusion-induced renal dysfunction, histological damage, and endothelin-1 overproduction after reperfusion. In contrast, pretreatment with L-NAME (1 or 10 mg/kg, i.v.) aggravated renal injuries of acute renal failure rats at 24 h after reperfusion, and the effect is accompanied by further increases in the renal endothelin-1 content at 2 and 6 h, but not at 24 h, after reperfusion. These results suggest that suppressive effects of NO on the renal endothelin-1 overproduction induced by ischemia/reperfusion in an early phase are probably responsible for the protective effect of NO against ischemic acute renal failure.     

卡巴胆碱减轻肠缺血/再灌注大鼠中性粒细胞活化和多器官损伤

目的探讨胆碱能激动剂——卡巴胆碱对肠缺血/再灌注大鼠中性粒细胞活化的影响及其对脏器功能的保护作用。方法雄性Wistar大鼠随机分为假手术组(N)、肠缺血/再灌注组(I/R)及卡巴胆碱组(Car)。夹闭肠系膜上动脉45min后恢复灌流制成肠I/R模型;卡巴胆碱组在肠缺血15min后经幽门注射卡巴胆碱(100μg/kg体质量)。于缺血45min(I45)、再灌注1h(R1)、2h(R2)、6h(R6)取肠系膜上静脉血进行中性粒细胞(PMN)计数、测定PMN呼吸爆发强度、检测反映脏器功能的血浆酶学指标以及肠和肺组织髓过氧化物酶(MPO)活性。结果肠缺血45min,PMN计数下降,再灌注后逐渐回升,至R6时达高峰。Car组PMN计数在R2和R6时显著低于I/R组大鼠;PMN呼吸爆发强度的变化规律与PMN计数一致。相关分析表明,PMN化学发光峰值变化和血PMN计数的变化呈正相关(r=0.748,P<0.05)。大鼠小肠组织MPO活性在肠缺血和再灌注均升高(P<0.05),R6达最高;Car组小肠MPO活性在肠I/R各时间点均显著低于I/R组(P<0.05～P<0.01)。肺组织MPO活性在肠缺血期降低,再灌注后逐渐升高,在R6时MPO活性达高峰(P<0.01),而此时Car组大鼠肺组织MPO活性仅为I/R组的31%(P<0.01),接近N组。GI/R组大鼠血浆天冬氨酸转氨酶(AST)、丙氨酸转氨酶(ALT)、肌酐(Cr)、肌酸激酶-同工酶(CK-MB)在肠缺血后均升高,R2时达峰值(P<0.01),R6时仍高于N组(P<0.05)。Car组大鼠各指标在再灌注后均较I/R组同时相点低,以R2组效果最明显(P<0.01)。结论卡巴胆碱能显著抑制PMN活化,减轻GI/R引起的多脏器功能损伤。     

仙人掌多糖对大鼠局灶性脑缺血的神经保护作用

摘要目的观察仙人掌多糖对大脑中动脉栓塞（MCAO）诱导的大鼠缺血 再灌注损伤的神经保护作用。方法雄性SD大鼠随机分为假手术组、缺血组、0.9%氯化钠溶液组、仙人掌多糖治疗组（200 mg·kg－1·d －1,ip）。采用MCAO法制作大鼠缺血 再灌注损伤模型。分别于大鼠缺血2 h再灌注3,6,8 h后进行神经行为学评分;8 h后2,3,5 三苯基氯化四氮唑（TTC）染色测定脑梗死体积;缺血2 h再灌注22 h后脑组织切片苏木精 伊红（HE）染色显微镜下形态学观察。结果与0.9%氯化钠溶液组相比,再灌注8 h后仙人掌多糖治疗组神经行为学评分平均下降（2.35±0.47）分（P＜0.05）,梗死灶体积减少（P＜0.05）;大鼠皮质及海马组织神经细胞丢失、神经胶质增生、核固缩、核深染等形态学均有明显改善（P＜0.05）。结论仙人掌多糖可以缓解大鼠大脑中动脉栓塞症状,具有一定的神经保护作用。     

凉膈散对肠缺血再灌注损伤大鼠肠道的保护作用

目的:观察凉膈散对大鼠缺血再灌注(I/R)损伤肠黏膜的保护作用.方法:健康Wistar大鼠168只,随机分为正常组、假手术组、模型组、凉膈散治疗组和凉隔散防治组,其中正常组8只,其他4组各40只.正常组不予任何处理,假手术组只分离不夹闭肠系膜上动脉,其余3组通过夹闭肠系膜上动脉建立大鼠小肠I/R模型,根据缺血45min后再灌注3、12、24、48和72h5个时相点义分为5组,每组8只大鼠.测定各组5个时点动物小肠黏膜病理损伤Chiu氏评分、门静脉血浆D-乳酸值、小肠组织匀浆丙二醛(MDA)含量和超氧化物歧化酶(SOD)活力、肠黏膜细胞凋亡指数及Bax表达水平.结果:模型组动物肠黏膜结构破坏明显,Chiu氏评分、血浆D-乳酸值明显升高.小肠匀浆MDA含量升高、SOD活力降低,肠黏膜细胞凋亡指数及Bax表达水平升高.凉膈散干预后,可减轻小肠黏膜病理损伤程度、与模型组比较,除3h外,门静脉血浆D-乳酸值下降,小肠组织匀浆MDA含量降低和SOD活力升高、肠黏膜细胞凋亡指数及Bax表达水平均下降.结论:I/R损伤可破坏肠黏膜屏障功能,凉膈散可通过减少机体氧自由基的生成而保护肠黏膜.     

The effect of inducible nitric oxide synthase inhibitor on microvascular permeability after cerebral ischemia/reperfusion

Our objective was to study the effect of inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (AG) on microvascular permeability after cerebral ischemia/reperfusion (I/R) injury. Cerebral I/R injury was produced by occlusion of both the carotid arteries for 60 min with restitution of blood flow for 60 min. AG (200 mg/kg) was intraperitoneally administrated 5 min before the onset of ischemia and again 5 min before reperfusion. Microvascular permeability was evaluated by 0.75% sodium fluorescein (FINa) extravasation during early 300 s. Cerebral I/R injury increased the permeability of microvessel to fluorescein and the concentration of fluorescein outside of microvessels was significantly higher than that in microvessels after 110 s. However, after AG administration, FINa extravasation appears much faster. From 80 s on, the fluorescence intensity outside is higher. I/R increased microvascular permeability. Nitric oxide derived from iNOS may maintain microvascular permeability at the early stage after I/R.     

金纳多对肾缺血/再灌注诱导的肾小管上皮细胞凋亡的影响

目的研究银杏叶提取物金纳多(Ginaton)注射液对大鼠肾脏缺血/再灌注(I/R)诱导的肾小管上皮细胞凋亡的保护作用及机制。方法采用双侧夹闭大鼠肾蒂缺血45min后再灌注20min、3、24h的方法制备动物模型。在预定时间点采用免疫印迹分析JNK及其底物c-Jun的激活和表达。TUNEL(原位末端标记法)及流式细胞术检测肾小管上皮细胞凋亡情况。结果肾脏缺血45min再灌注24h后肾小管上皮细胞凋亡明显增多,肾脏病理改变明显。肾脏缺血/再灌注20min时,JNK的磷酸化水平明显增加,缺血/再灌注3h,c-Jun的磷酸化水平明显增加。金纳多明显抑制了肾I/R诱导的JNK(vsI/R20min,P<0·05)和c-Jun(vsI/R3h,P<0·05)的磷酸化水平的增加。同时,金纳多明显减轻肾I/R诱导的肾小管上皮细胞凋亡(vsI/R24h,P<0·05),改善肾脏组织病理学改变。结论金纳多抑制肾I/R诱导的肾小管上皮细胞凋亡,保护缺血性肾损伤的作用,至少部分是通过抑制JNK通路的激活实现的。     

Effects of pre- and post-ischemic treatments with FK409, a nitric oxide donor, on ischemia/reperfusion-induced renal injury and endothelin-1 production in rats

We have demonstrated that ischemic acute renal failure (ARF) is attenuated by pre-ischemic treatment with a spontaneous nitric oxide (NO) donor, (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409). In the present study, we evaluated the effect of post-ischemic treatment with FK409 on ARF, compared with the pre-ischemic treatment effect. Ischemic ARF was induced by occlusion of the left renal artery and vein for 45 min followed by reperfusion, 2 weeks after contralateral nephrectomy. At 24 h after reperfusion, renal function in untreated ARF rats markedly decreased. In addition, increases in renal contents of endothelin-1 (ET-1), a deleterious mediator in the pathogenesis of ischemic ARF, were evident in untreated ARF rats at 24 h after reperfusion. Pre-ischemic treatment with FK409 (1 or 3 mg/kg, i.v.) at 5 min before ischemia attenuated ischemia/reperfusion-induced renal dysfunction and increased ET-1 contents after reperfusion. In contrast, post-ischemic treatment with FK409 (3 or 10 mg/kg, i.v.) at 6 h after reperfusion aggravated the renal injury, but did not affect the increased ET-1 content after reperfusion. These results suggest that pre-ischemic treatment with FK409 exerts renoprotective effects on ischemic ARF, probably through the suppression of renal ET-1 overproduction, whereas post-ischemic treatment with the NO donor worsens the ischemia/reperfusion-induced renal injury, through mechanisms unrelated to the ET-1 production after reperfusion.     

The effect of naringin, a bioflavonoid on ischemia-reperfusion induced renal injury in rats.

There is increasing evidence to suggest that toxic oxygen radicals play a role in the pathogenesis of ischemia/reperfusion (I/R) injury in the kidney. This study was designed to investigate the effects of naringin (Ng), a bioflavonoid in I/R induced renal failure in rats. The protective effect of naringin against the damage inflicted by reactive oxygen species (ROS) during renal I/R was investigated in Sprague-Dawley rats using histopathological and biochemical parameters. In one set of experiments animals were unilaterally nephrectomized, and subjected to 45 min of left renal pedicle occlusion and in another set both the renal pedicles were occluded for 45 min followed by 24h of reperfusion. Naringin (400 mg kg(-1), p.o.) was administered 60 min prior to ischemia. At the end of the reperfusion period, rats were sacrificed. Thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) levels, catalase (CAT), and superoxide dismutase (SOD) activities were determined in renal tissue. Serum creatinine and blood urea nitrogen (BUN) concentrations were measured for the evaluation of renal function. Ischemic control animals demonstrated severe deterioration of renal function, renal morphology and a significant renal oxidative stress. Pretreatment of animals with naringin markedly attenuated renal dysfunction, morphological alterations, reduced elevated TBARS levels and restored the depleted renal antioxidant enzymes. The findings imply that ROS play a causal role in I/R induced renal injury and naringin exert renoprotective effects probably by the radical scavenging and antioxidant activities.