大鼠肝脏冷灌注保存中肝细胞凋亡及其调控基因的研究

目的 通过检测凋亡细胞计数及凋亡相关基因bax和Fas的表达，探讨细胞凋亡及其相关基因在冷灌注保存大鼠肝脏组织中的作用。方法 本研究采用脱氧核糖核苷酸末端转移酶介导的末端标记法（TUNEL法）及RT-PCR，按照供肝保存时间30、60、90、120、180、300min分为6组进行凋亡细胞计数及其相关基因的检测。结果 不同保存时间大鼠肝脏组织中均有凋亡细胞发生，随着时间延长，凋亡细胞计数呈进行性增加趋势；未检测到bcl-2的表达，但可明显检测到bax和Fas基因的表达。结论 在冷灌注保存肝组织中，细胞凋亡是早期细胞死亡的主要原因之一。细胞凋亡的发生可能与bax和Fas的高表达以及bcl-2的低表达有关。     

丹参对大鼠供肝冷保存缺血再灌注损伤中肝细胞凋亡的影响

目的 探讨丹参对大鼠原位肝移植供肝冷保存缺血再灌注损伤中肝细胞凋亡的影响.方法 将40只SD大鼠分为对照组、实验组及假手术组,建立原位肝移植模型.供肝灌注冷保存以4℃乳酸林格氏液为基液,实验组加丹参注射液(60 ml/L),对照组不加丹参.保存5 h后植入受体.移植后6 h处死大鼠取样,检测血浆中ALT、AST水平;采用TUNEL法检测移植术后肝细胞凋亡情况;流式细胞仪检测凋亡相关基因Bcl-2、FasL蛋白的表达;光镜下观察移植肝脏病理形态学的改变.结果 再灌注后实验组ALT、AST显著低于对照组.与对照组比较,实验组肝细胞凋亡指数明显下降(F=133.802,P<0.05);肝组织中Bcl-2蛋白表达增加(F=91.063,P<0.01);FasL蛋白表达无明显变化(F=1.329,P>0.05);实验组与对照组比较肝组织形态学的再灌注损害程度明显减轻.结论 丹参可通过促进抑制凋亡基因Bcl-2蛋白的表达来抑制冷保存再灌注导致的肝细胞凋亡,对原位肝移植肝脏的缺血再灌注损伤有保护作用.     

缺血后处理对大鼠移植肝细胞凋亡的影响

目的：观察缺血后处理(ischemic postconditioning，Post-con)对大鼠移植肝细胞凋亡及 Caspase-3蛋白表 达的影响，探讨在体内条件下，缺血后处理对大鼠移植肝脏凋亡的保护机制。方法：采用 SD 大鼠原位肝移植动物模 型，供肝冷保存时间100min，无肝期控制于21min 内。48只雄性健康 SD 大鼠随机分为2组。对照组受体大鼠供肝 切除前及移植后无特殊处理；后处理组供肝植入后完全再灌注前，给予多次短暂复灌、复停作为缺血后处理。各组受 体一半(n=6) 于再灌注后2h 留取血液，检测血清肝功能指标和 TNF-α水平，另一半(n=6) 于再灌注后6h 取肝脏， 采用电镜、缺口末端标记法检测肝脏凋亡细胞，利用光学显微镜进行细胞计数；免疫组织化学检测 Caspase-3基因蛋 白表达，利用图像分析系统测量平均灰度值进行定量分析。结果：后处理组血清 AST、ALT、LDH 和 TNF-α含量均明 显低于对照组(P＜0． 05) ；组织的病理改变也明显轻于对照组；对照组凋亡细胞数为(112． 25±11． 73) 个/视野，后处理组 为(70． 36±18． 52) 个/视野，两组之间有显著差异(P＜0． 01) ；后处理组 Caspase-3蛋白表达明显下降(P＜0． 01) 。结论：缺 血后处理能够减轻再灌注损伤对移植肝的损害，明显抑制移植肝脏的细胞凋亡。这一作用可能是通过降低炎性细胞 因子水平，从而减少 Caspase-3蛋白表达而实现。     

bcl-2 mRNA、baX mRNA表达在三氧化二砷诱导肝癌细胞凋亡中的意义

目的 分析三氧化二砷(As2O3)诱导肝癌细胞凋亡中凋亡相关基因bcl—2 mRNA、bax mRNA表达的意义。方法 采用电镜、流式细胞仪、电泳及半定量RT—PCR方法检测不同剂量三氧化二砷诱导人肝癌细胞株bel—7402后凋亡的出现及bcl-2mRNA、bax mRNA的表达。结果 0．5にmol/L As2O3处理肝癌细胞未见凋亡，8μmol/L As2O3诱导肝癌细胞出现明显凋亡。对照组和药物组未检测到bcl-2 mRNA的表达，随浓度增加，bax mRNA的表达上调。结论 As2O3通过诱导凋亡抑制肝癌细胞株bel-7402的增殖，凋亡诱导基因bax mRNA的表达上调与此过程有关。bcl—2mR—NA表达与此过程无关。     

细胞凋亡在大鼠胰腺移植急性排斥反应中的作用

目的探讨细胞凋亡和相关因子Fas、FasL、bcl-2和bax在大鼠胰腺移植急性排斥反应中的作用,评价十二指肠黏膜活检在胰腺移植中诊断排斥反应的价值。方法选SD和Wistar大鼠行全胰十二指肠移植,实验分同基因胰腺移植组和异基因胰腺移植组。于移植术后第3、5及7d分批处死受体,取移植胰腺和十二指肠标本用HE染色和原位末端脱氧核糖核苷酸转移酶标记技术(TUNEL)检测移植物。免疫组化法检测移植后胰腺和十二指肠Fas、FasL、bcl-2和bax的表达。结果异基因胰腺移植组胰腺和十二指肠病理评分相同者占61.1%(11/18);评分不同者占38.9%(7/18),其中胰腺评分较高者6例,十二指肠黏膜评分较高者仅1例。异基因胰腺移植组胰腺和十二指肠病理学评分和细胞凋亡指数均明显高于同基因胰腺移植组(P<0.05,P<0.01)。胰腺和十二指肠细胞凋亡指数与急性排斥反应的病理学评分成正相关(r=0.965,P<0.01;r=0.942,P<0.01)。随着术后时间延长,排斥反应分级上升,细胞凋亡增加,FasL表达升高,在异基因移植组bcl-2表达下降,而Fas和bax表达无明显变化。结论细胞凋亡与移植胰腺急性排斥反应的严重程度呈正相关,细胞凋亡指数可作为判断移植物损伤程度的指标。FasL和bcl-2与胰腺移植急性排斥及组织损伤密切相关。十二指肠黏膜活检有助于判断有无胰腺急性排斥反应发生。     

大鼠移植胰腺冷缺血再灌注后细胞凋亡及其调控基因的研究

目的探讨胰腺移植再灌注后胰腺细胞凋亡发生的过程,以及Bax、Bcl2及Fas等调控基因的表达。方法65只SD大鼠随机分成7组假手术组,冷缺血2h组,冷缺血2h再灌注1、3、6、9、12h组。电镜观察胰腺组织的病理变化;采用缺口末端标记法(TUNEL)检测凋亡细胞;采用免疫组织化学方法检测胰腺组织中Bax、Bcl2及Fas蛋白的表达。结果胰腺移植后早期即可观察到细胞凋亡,凋亡的高峰期为再灌注后3h,凋亡指数(AI)为(95±29)%,P<001,再灌注6h组细胞凋亡有所减少,AI为(57±17)%,P<001,再灌注9h及12h组,AI分别为(36±16)%及(33±14)%,P<005。假手术组与冷缺血2h组均未见Bax、Fax蛋白表达。冷缺血再灌注1h组Bax( )、Fas( ),未见Bcl2蛋白表达;至冷缺血再灌注3h组Bax及Fas表达均增强,分别为Bax( )、Fas( ),以后各组表达有所下降。Bcl2蛋白在假手术组、冷缺血2h组及冷缺血再灌注1h组均未见表达,冷缺血再灌注3h及以后各组表达为( )。结论细胞凋亡是胰腺移植后的早期事件,Bax、Fas基因可能促进了胰腺细胞的凋亡,而Bcl2基因可能抑制细胞凋亡。     

小肠缺血再灌注后氧自由基和肝超微结构改变及凋亡相关基因的表达

目的:研究大鼠小肠缺血再灌注(I/R)后血中氧自由基的改变以及肝组织中bax、bcl-2、p53的表达及肝组织超微结构的变化,以探讨小肠I/R后肝绢织的损伤及其机制.方法:建立小肠I/R模型,分对照组、I/R后0 min、30 min、1 h、2 h、1 d、3 d及7 d共8组,于各时点检测血中一氧化氮(NO)和超氧化物岐化酶(SOD)的浓度,用免疫组织化学SP法观察肝组织中bax、bcl-2及p53的表达情况,透射电镜观察肝组织细胞超微结构变化.结果:大鼠小肠I/R后NO浓度在冉灌注0 min时升高,至冉灌注2 h时明显降低.其后又持续升高,至冉灌注7 d时达高峰.SOD的浓度变化则相反.再灌注0 min时肝组织中bax、bcl-2及p53阳性细胞率增高,再灌注30 min时阳性细胞率升高更为明显,但bcl-2表达高于bax,二者差别显著(P＜0.01).再灌注2 h时3种基因均有所降低,其后又开始升高,至再灌注7 d时阳性细胞率达高峰.bax表达明显高于bcl-2.二者差别显著(P＜0.01).透射电镜显示肝组织细胞超微结构损伤改变.结论:血中NO和SOD浓度的变化及肝组织中超微结构的改变表明,小肠I/R可引起肝组织细胞凋亡和损伤;而I/R后bax、bcl-2及p53阳性细胞在肝组织中的表达明显改变,可能与引起细胞凋亡和损伤有关.     

缺血预处理对鼠肝细胞凋亡及调控基因（bcl—2,Fas）蛋白表达的影响

目的观察鼠肝缺血再灌注损伤对肝细胞凋亡,以及缺血预处理对缺血再灌注损伤引起的肝细胞凋亡以及对其调控基因(bcl-2,Fas)蛋白表达的影响.方法Wistar大鼠分为假手术(SO)组、缺血再灌注(IR)组、缺血预处理(IP)组,后2组中分为3个亚组(IR1,2,3,IP1,2,3).缺血均为30min.缺血预处理为缺血前采用5min缺血及5min再灌.分别于再灌注1.5,3,4.5h后处死动物采取肝脏标本,SO组于术后3.5h采取肝标本.检测细胞凋亡及bcl-2,Fas蛋白表达水平.结果IR2组和IP2组与SO组比较细胞凋亡指数(AI)显著性增加(P<0.01),IP组较IR组细胞AI显著性降低(P<0.05).电镜示凋亡细胞,但IP组较IR组的细胞器特别是线粒体损伤要轻.bcl-2蛋白表达IP组较IR组及SO组显著性增加(P<0.05),IR组与SO组无差异(P>0.05).Fas蛋白表达IR2组和IP2组较SO显著性增高(P<0.05),IP组与IR组比较无显著性差异(P>0.05).结论IR损伤可能通过激活Fas蛋白的表达而促发肝细胞凋亡;IP可能通过激活bcl-2蛋白的表达而抑制肝细胞凋亡.     

低温保存-再灌注肝脏肝细胞凋亡与肝细胞糖原含量的关系及bax基因在其中的作用

目的　研究肝脏低温保存 再灌注期间肝细胞糖原含量与肝细胞凋亡之间的关系及bax基因在其中的作用。方法　制备糖原含量显著不同的 4组兔肝脏模型 ,根据给食方法的不同分为A组 (禁食 2 4h ,但自由饮水 )、B组 (标准实验室饮食 )、C组 (标准实验室饮食 +每 6h静脉滴注 2 5 %葡萄糖 3 0ml)及D组 (标准实验室饮食 +每 4h静脉滴注2 5 %葡萄糖 3 0ml) ,检测各组肝脏低温保存 再灌注期间肝细胞凋亡及bax基因蛋白的表达情况。结果　各组肝脏于低温保存 9h后再灌注 60min时 ,肝组织内可见明显的肝实质细胞凋亡现象 ,A、B、C、D 4组的凋亡细胞数量依次减少 ,4组间两两比较差异有统计学意义 ,各组肝细胞bax基因蛋白的表达程度与肝细胞糖原含量有密切的相关性。结论　肝脏低温保存 再灌注过程中 ,肝细胞内糖原能明显拮抗肝实质细胞凋亡的发生 ,其内在机理可能为肝细胞糖原通过抑制bax基因蛋白的表达从而达到拮抗肝实质细胞凋亡的发生。     

肝缺血再灌注细胞凋亡现象及Fas蛋白、PCNA 、p53、bcl-2 mRNA表达

目的：探讨肝缺血再灌注肝细胞凋亡发生的时空分布、基因表达特点及意义。方法：在观察SD大鼠（n=40）肝缺血0,30,45,60min再灌注3,6,24h存活率及病理形态基础上,重点观察大鼠（n=100)全肝血流阻断30min再灌注0,0.5,1,3,6,12,24,48,72,96h凋亡细胞分布（原位末端标记术,TUNEL）,G0-G1期细胞、凋亡细胞、增殖细胞指数分布（流式细胞术）,肝细胞显微及超微结构（光镜、电镜技术）,Fas蛋白、PCNA蛋白（免疫组化）及p53、bcl-2基因mRNA表达（原位杂交）。结果：缺血30min组多见细胞凋亡,细胞应答反应主要为三期：①急性期：再灌注0.5h Fas蛋白首先在血管周围高表达;②亚急期（3-24h):TUNEL阳性细胞在血管周围高分布,并向周围扩展;病理形态可见严重变性、细胞皱缩、细胞增殖三种变化;G1期细胞数大量减少,凋亡峰逐渐升高,12h后出现增殖峰,相关基因表达增强;③恢复早期（24-96h)：G1期细胞指数回升,凋亡峰和增殖峰持续并缓慢下降;相关基因表达陆续减弱。结论：肝缺血30min再灌注期机体可能通过下述基因调控途径影响细胞损伤应答反应：①Fas死亡基因与bcl-2存活基因的双重调控;②细胞凋亡与增殖双重调控;③经p53基因实现的细胞周期调控。     

bcl-2和Fas/FasL系统在肝癌细胞凋亡中的作用

目的 探讨ｂｃｌ－２和Ｆａｓ／ＦａｓＬ系统在肝癌细胞凋亡过程中的作用。方法 应用免疫组织化学方法检测３６例肝癌和４９例肝硬化组织中ｂｃｌ－２、Ｆａｓ和ＦａｓＬ的表达,用ＴＵＮＥＬ法检测肝中的细胞凋亡。结果 肝癌组织与肝硬化组织比较, 细胞明显减少;肝癌和肝硬化组织中ｂｃｌ－２的表达率分别为１６．６６％和６７．３４％;Ｆａｓ的表达率分别为５２．７７％和７３．４７％;ＦａｓＬ的表达率分别为７２．２２％     

骨关节炎软骨细胞凋亡调控基因的研究

目的　比较分析正常人及老年性骨关节炎患者软骨细胞bax和bcl 2的表达及细胞凋亡状况。　方法　取 9例骨关节炎患者的关节软骨做实验标本 ,以 6例无骨关节炎病史的意外死亡者关节软骨作为正常对照 ;采用逆转录 /聚合酶链反应 (RT PCR)方法检测bax和bcl 2mRNA表达 ,免疫组化检测bax和bcl 2蛋白 ;应用TUNEL方法进行凋亡细胞原位检测。　结果　骨关节炎患者和正常对照软骨细胞都能表达bax和bcl 2mRNA ;骨关节炎关节软骨细胞baxmRNA表达量较正常对照显著增高 (P <0 0 1) ,bcl 2mRNA表达量也高于正常对照组 (P <0 0 5 ) ,两组间bax/bcl 2表达量的比值差异无显著性意义 (P >0 0 5 ) ;免疫组化可检测到相应表达水平的蛋白 ;骨关节炎软骨细胞凋亡 (4%～ 14% )多于正常对照 (0～ 2 % )。　结论　软骨细胞凋亡受bax和bcl 2共同调节 ;bax和bcl 2的共同调节结果可能是OA患者软骨细胞凋亡增加 ,但凋亡率不高、病理过程进展缓慢的一个重要的原因     

Analysis of the Fas system and Bcl-2 in rat liver allograft rejection.

BACKGROUND: Apoptosis is involved in the mechanism of cell death observed in liver allograft rejection. The liver cells are sensitive to Fas-mediated apoptosis; however, little is known about the involvement of the Fas system in liver allograft rejection. We used rat models to investigate the expression of Fas/Fas ligand and apoptosis-related proteins during liver allograft rejection. MATERIALS AND METHODS: DA rats to Lewis, and Lewis to Lewis orthotopic liver transplantation were performed; liver samples were collected on days 1, 3, 5, 7, and 9 postoperatively (each n = 3). Apoptosis was monitored by TUNEL and electron microscopy. The expression of Fas, FasL, bcl-2, and bax was examined at the mRNA level and by means of immunohistochemistry. RESULTS: The TUNEL index in the allografts and isografts on day 7 was 20.1 +/- 1.5 and 7.7 +/- 2.6/1000 cells, respectively. Fas and bax mRNA were constitutively expressed in both of the groups. The expression of Fas ligand mRNA in the allografts which rose on day 5 was 10 times stronger compared to that in the isografts. On the other hand, bcl-2 mRNA was generally expressed in the isografts while it decreased in the allografts. The immunohistochemical analysis also showed an increased reactivity of Fas ligand on day 5 in the allograft, which was observed both in parenchymal and nonparenchymal cells. CONCLUSIONS: These results strongly suggest that Fas/Fas ligand interaction mediates the liver injury during allograft rejection. In addition, other regulatory factors of apoptosis, such as bcl-2, might also be involved in this pathogenesis.     

钙离子阻滞剂对移植肝再灌注损伤的保护作用

目的：研究钙离子阻滞剂在大鼠移植肝中的保护作用。方法：采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记（TUNEL）法和逆转录-多聚酶链反应（RT-PCR）法，以尼莫地平来处理大鼠，将132只大鼠分为2组，观察肝组织中细胞凋亡及其相关基因。结果：非处理组的凋亡细胞计数分别为14.09％、15.79％、18.04％、21.02％、22.4％，处理组的凋亡细胞计数分别为12.07％、13.18％、14.68％、15.19％、16.14％。处理组Bcl-2的表达较非处理组再灌注前与再灌注后明显增加。结论：钙离子阻滞剂可以抑制细胞凋亡，可能通过诱导或抑制凋亡相关基因的表达而对细胞凋亡进行调控。     

Alleviation of ischemia-reperfusion injury in rat liver transplantation by induction of small interference RNA targeting Fas

Background Cellular apoptosis plays an important role in ischemia-reperfusion (I/R) injury during organ transplantation. Synthetic small interference RNA (siRNA) targeting apoptotic receptor Fas has proven effective to protect mice against hepatitis and renal I/R injury. The objective of this study is to investigate the silencing impact of Fas siRNA to alleviate I/R injury in rat liver transplantation. Materials and methods Rat hepatocytes (BRL cells) were transfected with three pairs of synthesized Fas siRNA; cells untreated and treated with GFP siRNA were taken as blank and siRNA control. The most effective Fas siRNA was chosen for in vivo experiments. Syngeneic orthotopic liver transplantation was performed in Fas siRNA group, siRNA control group, and blank control group of Sprague–Dawley rats. There were 25 pairs of rats in each group. siRNA transfection of donor rats was done with hydrodynamic injection method 48 h before liver procurement. Blood and liver samples were collected for evaluation of serum ALT levels, Fas protein and mRNA expression, and apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, 1, 3, 6, 12, and 24 h after liver transplantation. Results Fas siRNA2, which inhibited Fas gene expression much more than other siRNAs, was chosen for in vivo experiment. The serum ALT levels of Fas siRNA group were much less than those of blank and siRNA control groups 1, 3, 6, 12, and 24 h after blood reperfusion, indicating diminishing ischemia-reperfusion injury. Donor livers in Fas siRNA group had substantially less cell apoptosis. The expression of Fas mRNA and protein was reduced dramatically in the Fas siRNA group compared with the other two groups. Conclusion Fas-mediated apoptosis play an important role in I/R injury of rat liver transplantation. Silencing Fas by hydrodynamic injection of siRNA holds therapeutic promise to limit I/R injury.     

Expression of bcl-2 homologue mRNAs in rat liver allograft: rejection-induced cell apoptosis is associated with upregulation of bax and bcl-xs expression

Abstract Apoptosis is considered to play an important role in rejection of organ transplants, although the precise mechanism has not been elucidated. In this study, we screened for the expression of bcl-2 homologues (bcl-2, bax, bcl-xl, and bcl-xs) and Fas ligand (FasL) by RT-PCR method in grafts during acute rejection in rats following liver transplantation. Both bax and bcl-xs (inducers of apoptosis) mRNA levels increased steadily in the allografted group from postoperative day (POD) 2 to 8, while no remarkable changes of bcl-2 and bcl-xl expression (inhibitors of apoptosis) were recognized. Significant induction of FasL gene expression was observed in the allografted group on POD 4 and expression gradually decreased thereafter, although minimal FasL mRNA expression was seen in isografts. Our results indicated, for the first time, that rejection-induced cell apoptosis is closely associated with upregulation of bax and bcl-xs expression besides FasL, but not with down-regulation of bcl-xl.     

胆囊收缩素对胆管癌细胞凋亡的调节作用及机制

目的 探讨胆囊收缩素（CCK）对胆管癌细胞凋亡的调节作用及机制。方法 采用TUNEL染色、定量RT-PCR和反义寡核苷酸技术分别研究CCK-8S对QBC939人胆管癌细胞系诱发性凋亡指数（AI）和bcl-2/bax mRNA表达的影响、以及bcl-2在CCK抑制凋亡中的作用。结果CCK-8S组 AI显著降低、bcl-2mRNA表达显著增强,同时加入CCK受体拮抗剂L364.718或L365.206可拮抗;反义bcl-2寡核苷酸转染能逆转CCK-8S对凋亡的抑制作用。结论CCK能提高凋亡阈值、抑制胆管癌细胞凋亡,其机制与上调bcl-2基因表达有关。     

Role of the bcl-2/bax pathway in hepatocyte apoptosis during acute rejection after rat liver transplantation

Abstract It is well established that hepatocytes undergo apoptotic cell death in the course of rejection of liver grafts. The present study was designed to investigate the role of the bcl-2/bax pathway in liver allograft tissue. Orthotopic liver transplantation was performed in three groups of rats: group 1, a syngeneic combination (Lewis to Lewis), group 2, an allogeneic combination (ACI to Lewis), and group 3, an allogeneic combination (ACI to Lewis) treated with 15-deoxyspergualin. The number of apoptotic cells identified by the TUNEL method in the grafted liver reflected the severity of acute rejection. In group 1, both bcl-2 mRNA and bax mRNA were expressed in trace amounts. In group 2, bcl-2 mRNA was slightly expressed while the expression of bax mRNA rose steadily. In group 3, bcl-2 mRNA expression levels remained similar to group 1, while bax expression levels exceeded those in group 1, but were less than in group 2. Expression of bcl-2 mRNA was stationary in comparison with expression of bax mRNA. Significantly higher levels of bax mRNA were expressed from day 4 in group 2 than in group 1 (on postoperative days 4, 6, and 8, P < 0.05, group 2 vs group 1). We also investigated bax protein and results consistent with the mRNA analysis data were obtained. These findings suggest that apoptotic cell death in liver allograft rejection is regulated, at least in part, by bax.