NF-κB信号通路对高糖诱导的人脐静脉内皮细胞凋亡的作用

目的 研究高糖尤其是波动性高糖对人脐静脉内皮细胞（HUVEC）凋亡的影响,以及NF-κB信号通路在高糖诱导HUVEC凋亡中的作用。 方法 构建针对NF-κBp65 mRNA序列1566位点的重组RNAi腺病毒表达载体,并利用RNAi腺病毒抑制HUVEC p65表达。应用流式细胞术及脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TUNEL）研究NF-κB信号通路在高糖诱导HUVEC凋亡的作用。 结果 高糖（20.5 mmol/L或30.5 mmol/L）可以促进HUVEC凋亡。NF-κBp65 特异腺病毒感染HUVEC后,可以明显抑制高糖刺激的NF-κBp65核蛋白转录,使核内p65蛋白表达处于基础水平。TUNEL结果示高糖作用后5 d,高糖组细胞凋亡率显著高于正常葡萄糖组（25.81％±1.77％比8.20％±0.63％,P < 0.05）,Ad-DEST＋高糖组（26.10％±0.98％）与单独高糖组的细胞凋亡率差异无统计学意义（P > 0.05）。Ad-1566＋高糖组的细胞凋亡率（11.49％±0.92％）比Ad-DEST＋高糖组显著下降（P < 0.01）。TUNEL法及流式细胞术检测结果均显示NF-κBp65 特异腺病毒可以降低高糖诱导的HUVEC凋亡。结论 高糖可以促进HUVEC凋亡。腺病毒感染HUVEC可以明显抑制高糖刺激的NF-κBp65核转录,从而保护高糖作用的HUVEC凋亡。     

大鼠肝缺血再灌注损伤NF-κB与ICAM-1在脑组织的表达及意义

目的:观察大鼠在肝脏缺血再灌注(IR)过程中肝脏炎性细胞因子TNF-α、IL-1βmRNA表达与脑组织NF-κB、ICAM-1表达之间的关系,探讨肝脏IR是否可导致脑组织损伤及其可能的机制.方法: 选健康雄性Wister大鼠48只,随机分为对照组、缺血30min组(I组)、缺血30min再灌注组(IR组)、缺血30min再灌注后1h组(IR 1h组)、缺血30min再灌注后2h组(IR 2h组)、缺血30min再灌注后4h组(IR 4h组),每组8只.应用免疫组化法分别检测各组大鼠肝脏TNF-α及脑皮质、海马和下丘脑区NF-κB、ICAM-1的表达情况,应用原位杂交的方法检测肝脏IL-1βmRNA表达情况.结果:肝脏IR导致肝脏明显的损伤,表现为血清GPT、AKP、γ-GT升高(P<0.01),肝组织中TNF-α、IL-1βmRNA表达显著增加(P<0.01),肝细胞水肿,炎性细胞浸润,甚至细胞坏死.随着再灌注时间的延长,脑组织HE染色可见脑细胞水肿,甚至个别脑细胞坏死.与对照组比较, I组和IR组大鼠脑皮质、海马和下丘脑中NF-κB、ICAM-1表达的差异无统计学意义(P>0.05),IR 1h组、IR 2h组和IR 4h组的差异有统计学意义(P<0.05 ,P<0.01).IR 1h、IR 2h、IR 4h组与对照组、I组、IR组比较,各部位脑组织NF-κB、ICAM-1的表达显著增加(P<0.05或P<0.01).各组大鼠不同部位脑组织间NF-κB、ICAM-1表达无统计学意义(P>0.05).结论:肝脏IR对脑组织可产生损伤性影响,NF-κB、ICAM-1介导的炎性细胞反应,参与了脑组织损伤的发生机制.     

异丙酚对大鼠缺血再灌注心肌Toll样受体4、NF-κB及血清IL-6的影响

目的 探讨异丙酚对大鼠缺血再灌注心肌Toll样受体4(TLR4)、核转录因子κB(NF-κB)和血清白细胞介素-6(IL-6)的影响.方法 健康雄性SD大鼠40只,体重200～250 g,随机分为4组,每组10只,假手术组(A组)左冠状动脉前降支只穿线;缺血再灌注组(B组)左冠状动脉前降支穿线结扎30 min后,再灌注120 min;A组和B组在缺血前10 min经股静脉注射生理盐水5 ml/kg后以5 ml·kg-1·h-1持续静脉输注至再灌注120 min;低剂量异丙酚组(C组)缺血前10 min经股静脉注射异丙酚5mg/kg后以5 mg·kg-1·h-1持续静脉输注至再灌注120 min,余处理同B组;高剂量异丙酚组(D组)缺血前10 min经股静脉注射异丙酚10 mg/kg后以10 mg·kg-1·h-1持续静脉输注至再灌注120 min,余处理同B组.再灌注120 min后,测定血清IL-6的浓度及心肌TLR4 mRNA、NF-κB蛋白的表达.结果 与A组比较,B组、C组及D组心肌TLR4 mRNA、NF-κB蛋白表达上调,血清IL-6水平升高;与B组比较,C组和D组心肌TLR4 mRNA、NF-κB蛋白表达下调,血清IL-6水平降低;与C组相比,D组心肌TLR4 mRNA、NF-κB蛋白表达下调,血清IL-6水平降低.结论 静脉注射异丙酚可抑制大鼠缺血再灌注心肌TLR4 mRNA、NF-κB的表达及血清IL-6浓度的升高,呈剂量依赖性.     

核因子κB抑制剂对缺血再灌注肌皮瓣的保护作用

目的观察核因子-κB(NF-κB)抑制剂二硫代氨基甲酸吡咯烷(PDTC)对肌皮瓣缺血再灌注(I／R)损伤的影响。方法湖北白种猪12头,随机分为对照组(A组)、I／R组(B组)及二硫代氨基甲酸吡咯烷(PDTC)处理组(C组)。采用放射免疫分析法检测I／R不同时点肌皮瓣静脉血浆肿瘤坏死因子(TNF)-α及白细胞介素(IL)-1β含量。观察组织髓过氧化酶(MPO)活性、水含量、肌细胞超微结构及肌肉存活比例变化。结果 C组再灌注1、2 h,TNF-α含量(0．69±0．15)、 (0．78±0．16)μg／L较B组(1．51±0．67)、(1．12±0．37)μg／L显著降低(P<0．01、P<0．05);再灌注1、2、4 h,IL-1β含量(0．17±0．09)、(0．18±0．06)、(0．17±0．07)μg／L较B组(0．43±0．17)、 (0．46±0．18)、(0．32±0．14)μg／L显著降低(P<0．01,P<0．01,P<0．05)。伴组织MPO活性、水含量显著降低(P<0．01),肌细胞线粒体损伤程度改善及肌肉存活比例的明显提高(P<0．01)。结论 PDTC能通过抑制TNF-α、IL-1β合成,减轻中性粒细胞浸润,有效防护肌皮瓣I／R损伤。     

黄芪甲苷预处理对小鼠肝脏缺血再灌注损伤的保护作用

目的 探讨黄芪甲苷( astragalosideⅣ)预处理对小鼠肝脏缺血再灌注损伤的保护作用及其机制.方法 将60只雄性C57BL/6小鼠分为4组,15只/组,A组:假手术对照组,B组:假手术黄芪甲苷组,C组:实验对照组,D组:黄芪甲苷实验组.黄芪甲苷组每只腹腔注射黄芪甲苷24 mg·kg-1·d-1,对照组每天腹腔注射等体积无菌生理盐水,共1周.建立小鼠肝脏部分缺血再灌注损伤模型,复流24h后采集标本,测定血清中转氨酶ALT和AST水平,光镜下观察H＆E染色肝组织病理学变化,酶联免疫吸附试验(ELISA)检测血清中IL-1β,IL-6,TNF-α的含量,采用Western blot 技术检测小鼠肝脏组织中核因子-κB (NF-κB)的表达.结果 黄芪甲苷实验组ALT及AST较实验对照组明显降低[AST:C组(4290±292) U/L vs.D组(2373±416) U/L,t=0.844;ALT:C组(4146 ±500) U/L vs.D组(2318 ±289) U/L,t =7.08,均P＜0.05],组织学损伤也明显减轻;ELISA 结果显示,黄芪甲苷预处理能明显降低外周IL-1β,IL-6,TNF-α的含量(IL-1 β:t 10.04;IL-6:t6.281;TNF-α:t =6.817;均P＜0.05).黄芪甲苷实验组肝脏组织中NF-κB表达量明显低于实验对照组.结论 黄芪甲苷预处理对小鼠肝脏缺血再灌注损伤有明显的保护作用.     

血管内皮细胞功能紊乱在下肢急性缺血-再灌注损伤中的作用及红花对其的影响

目的探讨血管内皮细胞功能紊乱在下肢急性缺血-再灌注损伤中的作用及红花对其的影响。方法将56例下肢缺血再通术患者分为下肢缺血一再灌注组(Ⅰ组，n=30例)和下肢缺血一再灌注加红花治疗组(U组，n=26例)，测定术前、术后30min、术后12h、术后24h、术后7d共5个时相点的血浆脱落内皮细胞(CEC)计数、肌酸激酶(CK)、乳酸脱氢酶(LDH)活性。结果下肢缺血一再灌注期间CEC、CK、LDH明显升高，尤以再灌注12h为著，随后开始下降：红花治疗组各个时相的CEC计数及CK和LDH均显著低于非治疗组(P＜0．001)。结论下肢缺血-再灌注可导致血管内皮细胞功能紊乱，红花通过保护内皮细胞功能而减轻下肢缺血一再灌注损伤。     

吡咯烷二巯基氨甲酸对大鼠肾缺血再灌注的保护作用及机制

目的 探讨吡咯烷二巯基氨甲酸(PDTC)对大鼠肾缺血再灌注的保护作用及可能的机制.方法 选择成年、健康及雄性的Wistar大鼠56只,随机分为缺血再灌注损伤(IRI)组,PDTC组及对照组.IRI组:24只,建立大鼠肾缺血再灌注模型;PDTC组:24只,缺血再灌注前15 min经鼠尾静脉注射PDTC 150 mg/kg,其余步骤同IRI组;对照组:8只,不给予缺血再灌注处理.IRI组和PDTC组分别于再灌注后2、6和24 h检测大鼠血清肌酐(Cr)和尿素氮(BUN)水平;检测肾组织中自细胞介素8(IL-8)和肿瘤坏死因子α(TNF-α)的含量;逆转录聚合酶链反应(RT-PCR)检测肾组织中核因子-κB(NF-κB)和诱导型一氧化氮合酶(iNOS)mRNA表达水平;苏木素-伊红(HE)染色观察大鼠肾组织的病理变化.取对照组的各项数据作为正常对照.结果 IRI组大鼠再灌注后各时间点的血Cr、BUN、IL-8及TNF-α含量、NF-κB和iNOS mRNA表达水平均高于对照组和PDTC组(P<0.05).再灌注后6 h时,PDTC组大鼠肾组织中IL-8和TNF-α含量与对照组比较,差异无统计学意义(P>0.05).再灌注后24 h时,PDTC组大鼠各项生化指标与对照组相比,差异均无统计学意义(P>0.05).PDTC组大鼠肾损伤的病理变化较IRI大鼠明显减轻.结论 PDTC通过抑制NF-κB,有效减少IL-8,TNFα和iNOS的产生,对肾缺血再灌注有良好的保护作用.     

白细胞介素-33调节Th1/Th2细胞对小鼠肝热缺血再灌注损伤的保护作用

目的 研究白细胞介素(interleukin,IL)-33对小鼠肝热缺血再灌注(ischemia/reperfusion,I/R)损伤的保护作用,寻求缓解肝I/R损伤的有效方法.方法 采用小鼠肝脏热缺血再灌注损伤模型.首先检测小鼠肝脏I/R损伤时IL-33的mRNA和蛋白水平的变化.小鼠分对照组、模型组、重组IL-33干预组和抗ST2L抗体干预组,检测I/R损伤6h后天冬氨酸转氨酶(aspartateaminotransferase,AST)和丙氨酸转氨酶(alanine aminotransferase,ALT)水平、肝组织病理变化和血清肿瘤坏死因子(tumor necrosis factor,TNF)-α、干扰素(interferon,IFN)-γ、IL-4、IL-5、IL-13水平.结果 肝脏I/R损伤时,IL-33的mRNA和蛋白水平水平显著升高(t再灌注2h=-3.574,t再灌注6 h=-4.147; P＜0.05).重组IL-33干预后小鼠血清肝酶水平明显下降(tALT=4.592,tAST=3.471;P＜0.05),病理损伤程度减轻,IL-4、IL-5、IL-13水平升高(tIL-4=-4.995,tIL-5=-4.584,tIL-13=-4.431;P＜0.05),IFN-γ,水平下降(t=5.402,P＜0.05).抗ST2L抗体干预则有相反的作用.IL-33组和抗ST2L抗体组小鼠的血清TNF-α水平与模型组相比,差异无统计学意义(tTNF-α=0.261,P ＞0.05).结论 小鼠肝脏热缺血再灌注损伤时IL-33mRNA及血清蛋白表达水平显著增高,对发生I/R损伤的肝脏发挥保护作用,其机制可能与促进Th1/Th2平衡向后者偏移有关.     

缺血预处理对大鼠缺血再灌注肝组织NF-κB表达、炎症及氧化应激反应的影响

目的：探讨缺血预处理（IP）减轻大鼠肝缺血再灌注（I/R）损伤的作用及机制。
　　方法：将15只雄性SD大鼠随机均分为假手术组、I/R组、IP+I/R组,采用Pringle法制作肝I/R模型（缺血30min+再灌注3h）,IP采用I/R前肝缺血10min+再灌注10min诱导。各组大鼠于再灌注3h后处死取材,行肝组织病理学、血请谷草转氨酶（AST）、谷丙转氨酶（ALT）检测,同时检测肝组织NF-κB蛋白的表达,以及炎性细胞因子IL-1β、TNF-α与氧化应激指标丙二醛（MDA）、髓过氧化物酶（MPO）水平。
　　结果：除假手术组外,I/R组与IP+I/R组大鼠肝组织均出现肝损伤是病理学改变,IP+I/R组的损伤程度明显轻于I/R组;与假手术组比较,I/R组与IP+I/R组大鼠血清AST、ALT水平明显升高,肝组织NF-κB蛋白表达、IL-1β与TNF-α水平、MDA与MPO浓度均明显升高（均P<0.05）,但IP+I/R组的各指标的升高幅度均明显小于I/R组（均P<0.05）。
　　结论：IP减轻大鼠肝I/R损伤的作用与抑制NF-κB活性,从而减轻炎症与氧化应激反应有关。     

一氧化氮对大鼠肝脏缺血再灌注后白细胞-内皮细胞粘附的影响

本文复制大鼠肝脏原位隔离冷灌注模型，利用一氧化氮合酶(NOS)的增强剂L-精氨酸(L-arg)和抑制剂N-硝基-L-精氨酸甲酯(L-NAME)，探讨了大鼠肝脏缺血再灌注后NO的作用机制。     

严重烧伤后中性粒细胞对血管内皮细胞形态与功能的影响及参麦注射液对其作用的实验研究

目的 了解严重烧伤后中性粒细胞(PMN)对血管内皮细胞形态与功能的影响及参麦注射液对内皮细胞的保护作用.方法 从健康体检者和烧伤患者(伤后6、24、48 h)静脉血中分离出PMN,与血管内皮细胞株ECV304体外共培养,采用噻唑蓝法检测ECV304细胞活力.放射免疫法检测培养上清液中内皮素1、一氧化氮(NO)的含量,并计算两者的比值(内皮素1/NO).另取伤后24 h血液标本与ECV304共培养,分别加入等渗盐水及0.5、2.0、8.0 g/L参麦注射液各100 μL,观察参麦注射液对上述指标及ECV304形态的影响.结果 与健康体检者比较,在伤后6 h的PMN刺激下ECV304活力明显下降、内皮素1含量明显上升(P＜0.01),伤后24 h的PMN刺激时尤为显著;而伤后6 h在PMN刺激下NO含量明显上升达峰值[(48.9±2.6)μmol/L,P＜0.01],伤后24,48 hPMN刺激ECV304的NO含量与健康体检者比较,无明显差异(P＞0.05);内皮素1/NO的变化趋势同内皮素1.加入不同浓度参麦注射液共培养后,可使内皮细胞活力明显上升、内皮素1含量明显下降、NO含量明显升高,其中中浓度参麦注射液可使体系中内皮细胞形态近似正常.结论 严重烧伤后PMN对血管内皮细胞形态、细胞活力、内皮素1/NO均有不同程度的影响,且以伤后24 h的PMN刺激最明显;参麦注射液可以改善上述情况,对严重烧伤后血管内皮细胞损伤具有保护作用.     

Interaction between neutrophils and endothelial cells following ischemia/reperfusion]

The adherence of activated neutrophils to endothelial cells during ischemia/reperfusion injury is mediated by inside-out signal transduction. Subsequently, outside-in signal transduction occurs following ligation of adhesion molecules with their ligands triggering respiratory bursts of neutrophils. In addition, neutrophil elastase enhances CC- and CXC-chemokine production by monocytes and macrophages. MCP-1, a CC-chemokine, enhances tissue factor production by macrophages and increases ICAM-1 expression on endothelial cells. Chemotaxis and respiratory bursts of neutrophils are augmented by CXC-chemokines. Furthermore, neutrophil elastase inactivates anticoagulants including antithrombin III, heparin cofactor II, and thrombomodulin, suggesting that neutrophil elastase aggravates microcirculatory disturbance after ischemia/reperfusion. Thus neutrophil elastase modulates the interation of neutrophils and endothelial cells during ischemia/reperfusion injury. Taken together with these observations, a therapeutic regimen with antibodies against adhesion molecules in combination with neutrophil elastase inhibitor and anticoagulants may attenuate ischemia/reperfusion injury.     

Augmentation of ischemia/reperfusion injury to endothelial cells by cyclosporin A

Ischemia/reperfusion (I/R) carries significant injury to endothelial cells in transplanted organs and is an important factor in chronic rejection. Immunosuppressive drugs, notably cyclosporin A (CyA) and FK506, can potentially augment this injury. Here, our goal was to determine the combined effects of I/R and CyA or FK506 on endothelial cells. Transformed mouse endothelial cells (SVEC 4-10) were subjected to ischemia or I/R for 2-24 hours by incubating cells in 100 per cent N2 (ischemia) followed by 5 per cent CO2 and 95 per cent O2 (reperfusion) for 24 hours. In separate experiments, CyA or FK506 was added to cells subjected to ischemia or I/R. Nonviable cells were determined by Trypan blue exclusion assay. All experiments (done in triplicate) were analyzed by Student's t test. Increasing ischemia times resulted in a greater number of nonviable cells (2% nonviable cells at 0 hours and 57% at 24 hours of I/R). Addition of CyA significantly increased the number of nonviable cells when compared with the control (I/R only) group (P = 0.014). Interestingly, FK506 did not increase the percentage of nonviable cells compared with the control group (P = 0.2). Unlike FK506, CyA augments I/R injury to endothelial cells in vitro. These findings could be relevant in chronic rejection and transplantation.     

Effects of adrenomedullin and vascular endothelial growth factor on ischemia/reperfusion injury in skeletal muscle in rats

Background

In this study we investigated the effects of adrenomedullin (AM) and vascular endothelial growth factor (VEGF) on skeletal muscle ischemia/reperfusion (I/R) injury in a rat model.

Materials and methods

Thirty-six Wistar rats were randomized into six groups (n = 6). Laparotomy was performed in all groups under general anesthesia. Nothing else was done in Group S (Sham). The Group I/R underwent I/R performed by clamping and declamping of the infrarenal abdominal aorta for 120 min, respectively. Group VEGF and Group AM received intravenous infusion of VEGF (0.8 μg/kg) or AM (12 μg/kg) respectively, without I/R. Group I/R + VEGF and Group I/R + AM received intravenous infusion of VEGF (0.8 μg/kg) or AM (12 μg/kg) immediately after 2 h period of ischemia, respectively. At the end of reperfusion period, skeletal muscle samples of lower extremity were taken from all groups for biochemical and histopathologic examinations.

Results

Tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO), and hypoxia inducible factor 1 alpha (HIF 1α) were found to be significantly higher in Group I/R than the levels in Group S (P < 0.05). Tissue levels of MDA, SOD, NO, and HIF 1α were significantly lower in Group I/R + AM compared with the levels in Group I/R (P < 0.05). In Group I/R + VEGF, tissue levels of MDA and NO were significantly lower than the levels in Group I/R (P < 0.05). No statistically significant difference was found in the tissue levels of catalase among the groups. Histologic examination revealed a larger central muscular necrosis than the peripheral necrosis, red blood cells in the lumens of capillary vessels, and a stronger atrophy and elliptical or round shape in muscle fibers in Group I/R. Terminal deoxynucleotidyl transferase mediated dUPT nick end labeling (TUNEL)-positive cell count was significantly lower in groups I/R + AM and I/R + VEGF than Group I/R (P < 0.0001, P < 0.0001, respectively).

Conclusions

These results indicate that AM and VEGF have protective effects on I/R injury in skeletal muscle in a rat model.     

缺血再灌注损伤后小鼠肾脏血管内皮生长因子C的表达

目的探讨小鼠肾缺血再灌注损伤模型中血管内皮生长因子C的表达变化及其意义。方法建立小鼠肾缺血再灌注损伤模型。雄性C57BL／6小鼠用无创性动脉夹夹闭左肾动脉,置于32℃温箱后1h松开血管夹,取出右肾。Sham组操作同上,但不夹闭左肾动脉。再灌注0,6,12,24,48h后处死小鼠,收集外周血及肾脏标本。测定血肌酐（SCr）和尿素氮（BUN）水平。HE染色观察Sham组和缺血再灌注24h组（IR24h组）肾脏病理学变化,免疫组织化学检测Sham组和IR24h组血管内皮生长因子C（vascularendothelialgrowthfactorC,VEGF-C）在肾脏的表达及分布,连续切片检测VEGF-C与其受体血管内皮生长因子受体3（VEGFR-3）的共定位。Westernblot检测缺血后不同灌注时间VEGF-C的表达变化。结果小鼠肾脏缺血再灌注损伤后,SCr和BUN水平上升,且随着再灌注时间的延长肾功能损伤逐渐加重,再灌注24h时肾功能损伤最明显,再灌注48h时肾功能已经有部分恢复。与Sham组比较,缺血再灌注24h肾脏组织肾小管管腔扩张,内有管型形成,肾小管上皮细胞肿胀坏死,空泡变性,刷状缘坏死脱落,并且伴有炎性细胞侵润,而肾小球未见明显病变。免疫组织化学结果显示,与Sham组比较,缺血再灌注24h肾脏VEGF-C及其受体VEGFR-3的表达均明显增加,二者存在着共定位现象,且主要表达在肾脏皮髓质交界处及髓质部的肾小管。Westernblot结果显示随着缺血后再灌注时间的延长,VEGF-C的表达增加。结论肾缺血再灌注损伤后存在肾脏VEGF-C的表达上升,且与其受体VEGFR-3的表达增加呈共定位,推测VEGF-C可能参与了肾脏缺血再灌注损伤。     

右美托咪定对脏器缺血/再灌注损伤的保护作用机制

背景 右美托咪定(dexmedetomidine,Dex)是一种新型高选择性α2-肾上腺素受体(alpha-2-adrenergic receptor,α2-AR)激动剂,Dex除具有镇静、镇痛、围术期交感阻滞的作用外,大量的研究表明Dex对多脏器的缺血/再灌注损伤(ischemidreperfusion injury,I/RI)具有保护作用. 目的 综述国内外Dex对多脏器I/RI保护机制的研究进展,为Dex脏器保护机制的研究提供思路. 内容 Dex通过减轻再灌注过程中的氧化应激反应,降低炎性因子的表达,减少机体细胞凋亡,保护红细胞变形能力来发挥脏器保护作用. 趋势 随着Dex对多脏器I/RI的保护机制不断被阐明,将为其临床应用提供更为深入的理论基础.     

骨髓间充质干细胞干预对缺血再灌注致小鼠肾小管上皮细胞损伤的保护作用

目的 观察骨髓间充质干细胞(MSCs)干预对缺血再灌注(I/R)诱导的急性肾损伤小鼠肾小管上皮细胞(RTECs)自身修复的影响.方法 Percoll密度梯度离心结合贴壁培养法分离纯化出C57BL/6小鼠的骨髓间充质干细胞(mMSCs),5-溴脱氧尿嘧啶核苷(BrdU)标记.雄性C57BL/6小鼠45只,分为正常对照组(15只)、I/R组(15只、夹闭双侧肾蒂30 min开放)、I/R+Brdu-mMSCs组(15只、夹闭双侧肾蒂30 min开放的同时尾静脉注射BrdU标记的mMSCs).留取动脉血及肾组织,检测血尿素氮(BUN)及肌酐(Scr)水平,制作肾组织切片行苏木素-伊红(HE)染色,荧光组织化学观察mMSCs在受体小鼠肾组织的分布,免疫组织化学观察RTECs增强细胞核抗原(PCNA)的表达,TUNEL法检测RTECs凋亡,Western blot检测建模后第2天肾小管组织中Caspase-3、bcl-2蛋白的表达.结果 BrdU标记mMSCs的阳性率可达(98.71±0.32)%.I/R+BrdU-mMSCs组小鼠的BUN及Scr水平较I/R组为低,肾小管损伤病理明显减轻,且小鼠的肾脏中可检测到BrdU+细胞的分布.mMSCs干预后,RTECs细胞核PCNA阳性表达明显增多(P＜0.05或P＜0.01),而细胞凋亡的水平却较I/R组明显减少(P＜0.05或P＜0.01).Western blot进一步显示:I/R+BrdU-mMSCs组小鼠的肾组织中Caspase-3蛋白水平明显下降[(1.16±0.33)比(1.64±0.27),P＜0.01],而bcl-2水平却明显增高[(0.94±0.27)比(0.68 ±0.15),P＜0.01].结论 小鼠发生I/R诱导的急性肾损伤后可诱导移植的MSCs向损伤肾组织归巢,锚定在肾脏的MSCs可促进损伤RTECs的再生,抑制其凋亡,从而有助于RTECs的自身修复,延缓肾损害进展.

Abstract：

Objective To observe the effects of mesenchymal stem cells (MSCs) on self-repair of renal tubular epithelial cells ( RTECs) in mice under ischemia/reperfusion ( IR). Methods MSCs in C57BL/6 mice were successfully isolated by Percoll density gradient centrifugation and adherence cultivation, then marked with BrdU. Forty-five healthy male C57BL/6 mice were assigned to control group (n =15 ) , I/R group (n = 15 , clamping bilateral renal pedicles and then reopening after 30 min) , I/R + BrdU-MSCs group (n = 15 , clamping bilateral renal pedicles and then reopening after 30 min, meanwhile, BrdU-marked MSCs were injected through caudal vein into the body of model mice). One, 2,3,7 and 14 days later, the mice were killed (n = 3/each group) , and blood and kidneys were obtained. Serum creatinine (Scr) and urea nitrogen (BUN) were determined, and mice kidneys were stained with Hematoxylin and Eosin ( HE) to observe their pathological changes. The distribution of MSCs in mice was observed by using fluorescence histochemistry. The expression of proliferating cell nuclear antigen ( PCNA) in RTECs was assessed by using immunohistological staining. The apoptosis of RTECs was detected by using TUNEL. The protein levels of Caspase-3 and bcl-2 in renal tubules on the day 2 after establishing the model were detected by using Western blotting. Results The positive BrdU marking ratio was (98. 71 ±0. 32) % in MSCs.As compared with I/R group, the levels of BUN and Scr in I/R + BrdU-MSCs group were significantly reduced, and pathological changes in renal tubules were alleviated significantly. BrdU-marked MSCs desposited in the kidneys of I/R + BrdU-MSCs group. The positive PCNA expression of RTECs was increased significantly after intervention of BrdU-MSCs (P ＜0. 05 or P ＜0. 01) , while the apoptosis relieved significantly. Western blotting analysis revealed: as compared with I/R group, the level of Caspase-3 in I/R + BrdU-MSCs group was decreased notably [(1.16±0.33) vs (1.64±0.27), P＜0.01], while the level of bcl-2 increased significantly [(0.94±0.27) vs (0.68±0.15), P＜0.01). Conclusion Acute renal injury by I/R can induce MSCs homing to injured kidney and anchoring here. The anchored MSCs can contribute to RTECs' self-repair of mice under ischemia/reperfusion, inhibit their apoptosis, which is helpful to the RTECs' self-repair and can delay the progression of renal injury.