大鼠肝脏缺血-再灌注损伤时齐墩果酸对氧自由基的影响

目的 探讨齐墩果酸(OA)对大鼠肝脏缺血-再灌注损伤时氧自由基的影响.方法 128只雄性SD大鼠随机分为假手术组(SH组)、缺血-再灌注组(IR组)、羧甲基纤维素钠(CMC-Na组)和OA组.建立70%肝脏缺血-再灌注模型,测定肝脏缺血60 min再灌注0、3、6、12 h后血清ALT活性和肝组织丙二醛(MDA)水平、超氧化物歧化酶(SOD)活性、谷胱甘肽(GSH)水平.结果 再灌注3、6、12 h,IR组、CMC-Na组、OA组血清ALT活性、肝组织MDA水平分别显著高于SH组(P<0.05),肝组织SOD活性、GSH水平分别明显低于SH组(P<0.05);OA组ALT活性、MDA水平分别较IR组和CMC-Na组明显降低(P<0.05),SOD活性和GSH水平分别较IR组和CMC-Na组显著升高(P<0.05).结论 OA对肝脏缺血-再灌注损伤具有一定保护作用,其抗肝脏缺血-再灌注损伤作用与抑制自由基的生成和释放有关.     

异丙酚后处理联合缺血后处理对大鼠肝脏缺血再灌注损伤的影响

目的 探讨异丙酚后处理联合缺血后处理对大鼠肝脏缺血再灌注损伤的影响.方法 健康雄性sD大鼠30只,体重200～250 g,随机分为5组(n=6),假手术组(Ⅰ组)仅开腹;缺血再灌注组(11组)肝脏缺血1 h再灌注4 h;缺血后处理组(Ⅲ组)肝脏缺血1 h后,再灌注10 8,缺血10 8,重复6次进行缺血后处理;异丙酚后处理组(Ⅳ组)肝脏缺血1 h后经尾静脉注射异丙酚10 mg/kg,随后静脉输注异丙酚40 mg·kg~(-1)·h~(-1) h;异丙酚后处理+缺血后处理组(V组)肝脏缺血1 h后进行异丙酚后处理及缺血后处理.于再灌注4 h时测定血清ALT活性、肝组织MDA含量、SOD活性、Bcl-2及Bax的蛋白表达水平,电镜下观察肝细胞超微结构.结果 与Ⅰ组比较,Ⅱ组～Ⅴ组血清ALT活性及肝组织MDA含量升高,肝组织Bcl-2蛋白表达上调,Ⅲ组-Ⅴ组肝组织SOD活性升高,Ⅱ组、Ⅲ组及Ⅴ组肝组织Bax蛋白表达上调(P<0.05或0.01);与Ⅱ组比较,Ⅲ组-Ⅴ组血清ALT活性及肝组织MDA含量降低,肝组织SOD活性升高,Bcl-2蛋白表达上调,Bax蛋白表达下调(P<0.05或0.01);与Ⅲ组比较,Ⅳ组血清ALT活性及肝组织MDA含量降低(P<0.05或0.01).Ⅲ组-Ⅴ组肝组织病理学损伤较Ⅱ组明显减轻.结论 异丙酚后处理联合缺血后处理可减轻大鼠肝脏缺血再灌注损伤,与异丙酚后处理单独应用时效果相同,其机制可能与抑制肝组织脂质过氧化反应及细胞凋亡有关.     

氢吗啡酮预处理对大鼠视网膜缺血-再灌注损伤的影响

目的观察氢吗啡酮预处理对大鼠视网膜缺血-再灌注损伤的影响,并探讨其作用机制。方法SPF级SD大鼠48只,随机分为假手术组(C组)、缺血-再灌注组(IR组)、氢吗啡酮组(H组)和吗啡组(M组),每组12只。采用前房加压灌注的方法制备视网膜缺血-再灌注损伤模型。于缺血前15 min,H组颈内静脉注射氢吗啡酮0.1mg/kg,M组注射吗啡1mg/kg,C组和IR组注射等容量生理盐水。再灌注24 h后,取大鼠视网膜组织,采用HE染色法观察病理学变化,测定视网膜内层厚度及全层厚度;采用TUNEL法计算细胞凋亡指数(AI);采用免疫组化法检测Bax、Bcl-2、caspase-3蛋白含量;采用ELISA法检测TNF-α、IL-6浓度;采用硫代巴比妥酸及黄嘌呤氧化酶法分别检测MDA浓度和SOD活性。结果与C组比较,IR组视网膜出现病理学损伤,AI明显升高(P<0.05);Bax、caspase-3蛋白含量明显升高,Bcl-2蛋白含量和Bcl-2/Bax比值明显降低(P<0.05);TNF-α、IL-6和MDA浓度明显升高(P<0.05),SOD活性明显减弱(P<0.05)。与IR组比较,H组和M组视网膜组织病理学损伤明显减轻,AI明显降低(P<0.05);Bax、caspase-3蛋白含量明显降低,Bcl-2蛋白含量明显升高,Bcl-2/Bax比值明显升高(P<0.05);TNF-α、IL-6和MDA浓度明显降低,SOD活性明显增强(P<0.05)。结论氢吗啡酮可减轻大鼠视网膜缺血-再灌注损伤,其机制可能与改善视网膜细胞凋亡、炎症反应及氧化应激相关。     

七氟醚预处理对肝脏缺血-再灌注损伤及PI3K/Akt信号通路的影响

目的 探讨七氟醚预处理对肝脏缺血-再灌注损伤及磷脂酰肌醇3激酶/蛋白激酶B(PI3K/Akt)信号通路的影响.方法 48只成年SD大鼠随机分为假手术组(SH组)、缺血-再灌注组(IR组)、七氟醚预处理组(SI组)和七氟醚Wortmannin组(SW组),每组12只.除SH组外,IR组、SI组和SW组建立70％肝脏缺血-再灌注模型.检测大鼠血清谷草转氨酶(AST)和谷丙转氨酶( ALT)含量,并取再灌注的肝组织用ELISA法测IL-1β浓度,用Western Blot法测定肝组织的p-PI3K、p-Akt(ser473)、Akt等表达量;用HE染色进行病理学检查,观察肝细胞损伤及坏死情况.结果 与SW组比较,SI组ALT、AST和IL-1β浓度明显降低(P＜0.05),且p-PI3K、p-Akt(ser473)表达量明显增加(P＜0.05),肝组织损伤减轻.结论 七氟醚对肝脏缺血-再灌注损伤有保护作用,可能通过激活PI3K/Akt信号通路起作用.     

17-β雌二醇对大鼠肝切除肝缺血再灌注损伤肝细胞凋亡和Bcl-2、Bax表达的影响

目的 观察17-β雌二醇预处理对肝切除肝缺血再灌注损伤肝脏组织细胞凋亡及Bcl2、Bax表达的影响,并探讨其肝保护的机制.方法 建立大鼠肝切除肝缺血再灌注损伤模型,75只雄性SD大鼠随机分为3组:假手术组(Sham组)、缺血再灌注组(IR组)和17-β雌二醇预处理组(E2+ IR组).检测各组大鼠再灌注后lh、3h、6h、12 h、24 h肝功能变化.光镜下观察肝组织病理学改变.TUNEL法观察再灌注后12 h大鼠肝细胞凋亡情况、流式细胞学方法测定再灌注后12h肝细胞凋亡率.Western blot法检测再灌注后12 h Bcl-2和Bax的表达情况.结果 与Sham组相比,在IR组各时间点均可见ALT和AST增高,且在再灌注后的12h达到了最高值;病理学检查可见肝细胞肿胀,肝窦变窄,嗜中性粒细胞浸润和片状坏死等变化;在再灌注后12h,凋亡细胞增多及细胞凋亡率明显升高;肝脏组织Bcl 2表达减少,Bax的表达增加.17-β雌二醇预处理组在灌注后各时间点ALT和AST值明显下降,肝脏病理损伤改善;在再灌注后12h,凋亡细胞减少及细胞凋亡率明显降低,肝脏组织Bcl-2表达增加,Bax的表达减少.结论 17-β雌二醇对大鼠肝缺血再灌注损伤有明显的保护作用,其可能通过促进Bcl-2表达及抑制Bax表达,从而抑制肝细胞凋亡.     

亚低温对肝缺血再灌注损伤的保护作用

目的　探讨亚低温对肝缺血再灌注损伤的保护作用机制。方法　将 18只犬随机分为 3组 :非缺血对照组 (n =6 )、缺血再灌注组 (n =6 )和亚低温处理组 (肝周充填碎冰块造成肝脏亚低温 ,n =6 )。对各组肝上下腔静脉血进行谷丙转氨酶 (ALT)、谷草转氨酶(AST)、乳酸脱氢酶 (LHD )以及丙二醛 (MDA)和超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化酶 (GSH PX)活性及总抗氧化 (TAX )能力测定。结果　全肝缺血再灌注后ALT ,AST ,LDH和MDA含量明显上升 (P <0 .0 1) ,SOD ,CAT ,GSH PX活性及TAX能力明显下降 (P <0 .0 1) ;而亚低温处理组与缺血再灌注组比较 ,ALT ,AST ,LDH和MDA含量明显下降 (P <0 .0 1) ,SOD ,CAT ,GSH PX活性及TAX能力明显上升 (P <0 .0 1,P <0 .0 5 )。结论　亚低温能增强肝组织自身抗氧化能力 ,减轻肝缺血再灌注后氧自由基对肝脏的损伤。     

大鼠脂肪干细胞对自体肝移植缺血再灌注损伤的保护机制研究

目的探讨大鼠脂肪干细胞在大鼠自体肝移植缺血再灌注(ischemia-reperfusion,IR)损伤模型中的保护作用机制。方法分离并培养大鼠脂肪干细胞(adipose-derived stem cells,ADSCs),构建稳定细胞株。SD大鼠随机分为假手术组、自体肝移植缺血再灌注组(IR组)、自体肝移植缺血再灌注+脂肪干细胞回填组(ADSCs组),每组10只。假手术组上腹正中切口,暴露并离断肝脏韧带,不做其他处理。IR组用动脉夹夹闭肝门阻断血流,肝素注射液灌注15 min,不给药。ADSCs组在肝素注射液灌注后30 min尾静脉注射1×106 ADSCs。手术后24 h后处死大鼠,检测各组大鼠血清中天冬氨酸氨基转移酶(AST)、丙氨酸转氨酶(ALT)、肝脏超氧化物歧化酶(SOD)、丙二醛(MDA)含量,以及线粒体活性;苏木素-伊红染色(HE)观察肝脏病理学改变;免疫印迹法(Western blotting)检测细胞间黏附分子-1(ICAM-1)、Bax基因表达情况。结果与假手术组相比,IR组AST和ALT水平、MDA含量较高,SOD含量较低(P0.05),线粒体活性较弱。病理切片结果显示,IR组肝细胞出现坏死,炎性细胞浸润严重。Western blotting结果显示IR组较假手术组ICAM-1、Bax表达增多。与IR组相比,ADSCs组AST和ALT水平、MDA含量较低,SOD含量较高(P0.05),线粒体活性较强,炎性细胞浸润较少,ICAM-1、Bax表达减少。结论大鼠脂肪干细胞对大鼠自体肝移植缺血再灌注损伤模型有保护作用,其作用机制可能是通过减少炎症反应和氧化应激程度进而减轻肝脏缺血再灌注损伤。     

硫化氢对大鼠肝缺血再灌注损伤的影响

目的 评价硫化氢对大鼠肝缺血再灌注损伤的影响.方法 健康雄性SD大鼠30只,体重220～250 g,采用随机数字表法,将其随机分为假手术组(S组)、缺血再灌注组(IR组)和不同剂量硫化氢组(H2S1～3组),每组6只.S组仅暴露肝门,不夹闭动、静脉;IR组采用夹闭左、中叶肝蒂、门静脉和肝动脉支1h恢复灌注的方法制备大鼠肝缺血再灌注模型;H2S1～3组于再灌注前5min分别腹腔注射14、28、56 μmol/kg硫化氢钠.于再灌注6h时抽取下腔静脉血样并取肝组织,采用全自动生化分析仪测定血清谷丙转氨酶(ALT)和谷草转氨酶(AST)活性,采用二硫代二硝基苯甲酸法测定肝组织谷胱甘肽(GSH)含量,光镜下观察肝组织病理学结果.结果 与S组相比,IR组血清ALT和AST活性升高,肝组织GSH含量下降(P＜0.05);与IR组相比,H2S1～3组ALT和AST活性降低,肝组织GSH含量升高(P＜0.05);H2S1～3组肝病理学损伤较IR组明显减轻.结论 H2S可减轻大鼠肝缺血再灌注损伤.     

高渗氯化钠羟乙基淀粉40注射液高容量血液稀释对大鼠肝脏缺血再灌注损伤的影响

目的 探讨高渗氯化钠羟乙基淀粉40注射液高容量血液稀释对大鼠肝脏缺血再灌注损伤的影响.方法 雄性Wistar大鼠30只,体重300～350 g,随机分为3组(n=10):假手术组(S组)、缺血再灌注组(IR组)和高容量血液稀释组(HH组).S组仅开腹,不阻断血管;IR组阻断肝门静脉和左肝动脉30 min,再灌注2 h;HH组30 min内经尾静脉输注高渗氯化钠羟乙基淀粉40注射液10 ml/kg进行高容量血液稀释,输注完毕后15 min,行肝脏缺血再灌注.再灌注2 h时,下腔静脉取血样,测定血清谷丙转氨酶(ALT)和谷草转氨酶(AST)的活性;取左肝叶组织,光镜下观察病理学结果,采用比色法测定丙二醛(MDA)含量,采用黄嘌呤氧化酶法测定超氧化物歧化酶(SOD)活性.结果 与S组比较,IR组和HH组血清ALT和AST的活性、肝组织MDA含量升高,肝组织SOD活性降低(P<0.01),肝组织病理学损伤明显;与IR组比较,HH组血清ALT和AST的活性、肝组织MDA含量降低,肝组织SOD活性升高(P<0.01),肝组织病理学损伤减轻.结论 高渗氯化钠羟乙基淀粉40注射液高容量血液稀释可减轻大鼠肝脏缺血再灌注损伤,可能与氧自由基生成减少有关.     

氟比洛芬酯对大鼠肺缺血再灌注损伤的影响

目的 探讨氟比洛芬酯对大鼠肺缺血再灌注损伤的影响.方法 SPF级雄性健康成年SD大鼠60只,体重250 ～ 300 g,采用随机数字表法,将大鼠随机分为3组(n=20):假手术组(S组)、肺缺血再灌注组(IR组)和氟比洛芬酯组(FA组).采用阻断左肺门60 min再灌注120 min的方法制备肺缺血再灌注模型.FA组开胸前15 min经股静脉注射氟比洛芬酯10 mg/kg.于左肺门再灌注120 min时处死大鼠,取肺组织,计算肺湿干重比和凋亡指数,检测肺组织NF-κB活性、Bcl-2和Bax蛋白表达,计算Bcl-2/Bax比,并观察病理学结果.结果 与S组比较,IR组和FA组肺组织湿干重比、凋亡指数和NF-κB活性增强,Bcl-2和Bax蛋白表达上调,IR组Bcl-2/Bax比降低,FA组Bcl-2/Bax比升高(P＜0.01);与IR组比较,FA组肺组织湿干重比、凋亡指数和NF-κB活性降低,Bax蛋白表达下调,Bcl-2蛋白表达上调,Bcl-2/Bax比升高(P＜0.05).FA组肺组织病理学损伤较IR组减轻.结论 氟比洛芬酯可减轻大鼠肺缺血再灌注损伤,其机制与抑制NF-κB活化,改善Bcl-2和Bax平衡,从而抑制细胞凋亡有关.     

瑞芬太尼对肝硬化大鼠肝脏缺血再灌注损伤的影响

目的 探讨瑞芬太尼对肝硬化大鼠肝脏缺血再灌注损伤的影响.方法 成年健康雄性SD大鼠30只,体重260～300 g,采用随机数字表法,将其随机分为3组(n=10):肝硬化组(C组)、肝硬化+肝缺血再灌注组(I/R组)和瑞芬太尼组(R组).C组、I/R组和R组采用四因素综合法制备大鼠肝硬化模型,I/R组和R组在肝硬化模型制备成功后1周制备大鼠70％肝脏缺血再灌注模型,R组于缺血前10 min开始静脉输注瑞芬太尼1μg·kg-1·min-至再灌注结束.于再灌注4h时取静脉血样和肝组织,测定血清ALT和AST活性、肝细胞Bcl-2和Bax表达及肝细胞凋亡情况,计算细胞凋亡指数,光镜下观察肝组织病理学结果.结果 与C组比较,I/R组血清ALT和AST的活性升高,肝细胞Bcl-2表达下调,Bax表达上调,细胞凋亡指数升高(P＜0.05);与I/R组比较,R组血清ALT和AST的活性降低,肝细胞Bcl-2表达上调,Bax表达下调,细胞凋亡指数降低(P＜0.05).R组肝组织病理学损伤轻于I/R组.结论 瑞芬太尼可减轻肝硬化大鼠肝脏缺血再灌注损伤,其机制与平衡肝细胞Bcl-2与Bax表达而抑制肝细胞凋亡有关.     

PI3K/Akt信号通路在七氟醚后处理减轻大鼠局灶性脑缺血再灌注损伤中的作用

目的 评价磷脂酰肌醇3激酶/蛋白质丝氨酸苏氨酸激酶(PI3K/Akt)信号通路在七氟醚后处理减轻大鼠局灶性脑缺血再灌注损伤中的作用.方法 雄性SD大鼠64只,体重300～350 g,随机分为4组(n=16):局灶性脑缺血再灌注组(IR组)、七氟醚后处理组(SP组)、七氟醚后处理+Wortmannin组(SW组)和Wortmannin组(W组).采用电凝法阻断左侧大脑中动脉,夹闭双侧颈总动脉60 min恢复灌注的方法制备大鼠局灶性脑缺血再灌注模型.再灌注即刻SP组和SW组吸入2.5%七氟醚60 min,夹闭双侧颈总动脉30 min时SW组和W组股静脉输注Wortmannin 0.6 mg/kg.于再灌注24、48、72 h时行神经功能评分,最后1次评分后处死大鼠取脑,测定脑梗死体积,采用Western blot法检测左侧脑组织磷酸化Akt(p-Akt)和磷酸化Bad(p-Bad)的表达水平.结果 与IR组相比,SP组和SW组各时点神经功能评分升高,再灌注72 h时脑梗死体积比降低,脑组织p-Akt和p-Bad表达上调(P＜0.05),W组上述指标差异无统计学意义(P＞0.05);与SP组相比,SW组各时点神经功能评分降低,再灌注72 h时脑梗死体积比升高,脑组织p-Akt和p-Bad表达下调(P＜0.05).结论 PI3K/Akt信号通路激活后p-Bad表达上调可能参与了七氟醚后处理减轻大鼠局灶性脑缺血再灌注损伤的过程.     

Bax ablation protects against hepatic ischemia/reperfusion injury in transgenic mice.

Apoptosis appears to be a central mechanism of cell death following reperfusion of the ischemic liver. The aim of this study was to determine the effect of decreased expression of the proapoptotic Bax gene on hepatic apoptotic warm ischemia/reperfusion (I/R) injury. Three groups of mice were studied: homozygotic knockout mice (Bax-/-); heterozygotic (Bax+/-); and wild type (Bax+/+). Isolated mouse livers were subjected to 90 minutes of ischemia (37 degrees C) followed by 15 minutes of reperfusion. Bax and Bcl-2 expression in liver tissue homogenates was measured by Western blot. Serum liver enzyme levels were measured and intrahepatic caspase-3 activity was determined by fluorimetric assay. Oil red O (ORO) staining was performed for fat detection. Apoptotic cells were identified by morphological criteria, immunohistochemistry for caspase-3, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) assay. At 1 minute of reperfusion, the ischemic (Bax-/-) livers were characterized by statistically significantly lower liver enzyme levels and lower caspase-3 activity than the ischemic (Bax+/+) livers (P<0.05 for both). The reduction in postischemic apoptotic hepatic injury in the ischemic Bax-/- livers group was confirmed morphologically, by the significantly reduced microvesicular steatosis as determined by ORO staining, fewer apoptotic hepatocyte cells detected (P<0.05); immunohistochemically, by the significantly weaker activation of caspase-3 compared to the ischemic group (P<0.05); and by TUNEL assay (P<0.05). Similar levels of antiapoptotic Bcl-2 protein expression were detected in all 3 groups of ischemic livers on Western blots. Bax protein was not expressed in Bax-deficient livers and was detected in Bax+/+ normal livers. In the Bax+/- livers, levels of the damage markers were moderate. In conclusion, The better tolerance of Bax knockout livers to I/R injury suggests that the Bax gene may serve as a potential target for therapeutic intervention in hepatic I/R injury.     

Protective Effect of MESNA (2-Mercaptoethane Sulfonate) Against Hepatic Ischemia/Reperfusion Injury in Rats

Purpose Reoxygenation of ischemic tissue generates various reactive oxygen metabolites (ROMs), which have a deleterious effect on various cellular functions. We evaluated the possible protective effect of 2-mercaptoethane sulfonate (MESNA) on hepatic ischemia/reperfusion (I/R) injury.Methods Wistar albino rats were subjected to 45-min hepatic ischemia, followed by 60-min reperfusion. 2-Mercaptoethane sulfonate, 150 mg/kg, or saline was given intraperitoneally (i.p.) twice, 15 min before ischemia and immediately before reperfusioin. We measured serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels to assess liver function. Liver tissue samples were taken to measure the levels of malondialdehyde (MDA), an end-product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. We also measured hepatic collagen content, as a fibrosis marker.Results Plasma ALT and AST levels were higher in the I/R group than in the control group, but this increase was significantly decreased by MESNA treatment. Hepatic GSH levels, which were significantly depressed by I/R, increased back to the control levels in the MESNA-treated I/R group. Increases in tissue MDA levels and MPO activity caused by I/R injury decreased back to the control levels after MESNA treatment. Similarly, the increased hepatic collagen content in the I/R group decreased to the level of the control group after MESNA treatment.Conclusion The fact that MESNA alleviated I/R-induced injury of the liver and improved hepatic structure and function suggests that its antioxidant and oxidant scavenging properties may be of therapeutic value in protecting the liver against oxidative injury caused by I/R.     

Ambroxol Alleviates Hepatic Ischemia Reperfusion Injury by Antioxidant and Antiapoptotic Pathways

Background

Hepatic ischemia/reperfusion (HI/R) injury is a common pathologic process caused by many clinical settings, such as liver resection, liver transplantation, hypovolemic shock, and trauma. The use of ambroxol, which acts as a mucolytic agent, provides antioxidant and anti-inflammatory effects.

Methods

A rat model of HI/R was induced by clamping the hepatic artery, the hepatoportal vein, and the bile duct with a vascular clamp for 30 minutes followed by reperfusion for 6 hours under anesthesia. The sham group underwent laparotomy without hepatic ischemia. The ambroxol group was injected into the tail vein in the ambroxol group 5 minutes before HI/R at one dose of 20 mg/kg, 80 mg/kg, or 140 mg/kg. The control group underwent the same procedure as the ambroxol group but with administration of physiological saline. Liver injury was evaluated by biochemical and histopathological examinations. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were assayed in serum samples. Superoxide dismutase (SOD), catalase (CAT), malondiadehyde (MDA), and glutathione (GSH) were spectrophotometrically measured. Furthermore, caspase-3, Bcl-2 and Bax expression as well as the level of c-Jun N-terminal kinases (JNK) we estimated activation.

Results

Wistar rats that received 20, 80 mg or 140 mg of ambroxol displayed reduced HI/R injury compared with controls. Use of ambroxol reduced the histologic injury and significantly decreased serum ALT and AST levels. In addition, ambroxol enhanced the activity of hepatic tissue SOD and CAT, increasing GSH but decreasing MDA tissue contents. In the ambroxol group, Bcl-2 expression was increased and Bax and caspase-3 decreased compared with the controls. Furthermore, ambroxol reduced levels of phosphorylated JNK (P < .05).

Conclusion

These results indicated that ambroxol attenuated rat HI/R through upregulation of intracellular antioxidant and anti-apoptotic signaling pathways.     

瘦素预先给药对L02肝细胞缺氧复氧时细胞凋亡的影响

目的 探讨瘦素预先给药对L02肝细胞缺氧复氧时细胞凋亡的影响.方法 L02肝细胞接种于6孔培养板中,孵育24 h后,随机分为6组,每组6孔:对照组(C组)、缺氧复氧组(HR组)和不同浓度瘦素预处理组(L_(1～4)组).HR组于37℃95%N_2-5%CO_2培养箱中缺氧12 h,然后于37℃95%O_2-5%CO_2培养箱中复氧12 h;L_(1～4)组先分别加入瘦素100、200,400和800 μg/L,再进行缺氧复氧.取细胞上清液,采用赖氏法测定谷丙转氨酶(ALT)和谷草转氨酶(AST)的浓度;采用Hoechst 33342/PI双染色法测定细胞捌亡情况,计算细胞凋亡率;采用荧光定量PCR法测定Bax mRNA和Bcl-2 mRNA的表达.结果 与C组比较,HR组和L_(1～4)组ALT和AST的浓度升高,早期凋亡率和晚期凋亡率升高,Bax mRNA和Bcl-2 mRNA表达上调(P<0.01);与HR组比较,L_(1～4)组ALT和AST的浓度下降,早期凋亡率降低,L_3组Bax mRNA表达下调,L_2组和L_3组Bcl-2 mRNA表达上调(P<0.01);L_(1～4)组间ALT和AST的浓度、早期凋亡率和晚期凋亡率、Bax mRNA和Bcl-2 mRNA表达差异无统计学意义(P>0.05).结论 瘦素预先给药可抑制L02肝细胞缺氧复氧时细胞凋亡,其机制与上调肝细胞Bcl-2 mRNA的表达,下调Bax mRNA的表达有关.     

Augmenter of Liver Regeneration Attenuates Tubular Cell Apoptosis in Acute Kidney Injury in Rats: The Possible Mechanisms

Augmenter of liver regeneration (ALR), the expression of which increased in rat kidneys after renal ischemia/reperfusion (I/R) injury, enhances renal tubular cell regeneration in vivo and in vitro. We aimed to investigate the effects of ALR on apoptosis of renal tubular cells after renal I/R injury in vivo and consider the possible mechanisms. Rats that were subjected to bilateral renal ischemia for 60 min followed by reperfusion were administered with either vehicle or recombinant human ALR (rhALR). Renal dysfunction and histologic injury were assessed by the measurement of serum biochemical markers and histological grading. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL). Caspase-3 activity was measured using a colorimetric protease assay. Expression of Bcl-2, Bax Fas, phosphorylated-Akt (p-Akt), and phosphorylated-p53 (p-p53) was determined by western blotting. Compared with vehicle-treated rats, renal dysfunction and histologic injury were significantly attenuated by administration of rhALR. The number of TUNEL-positive tubular cells and caspase-3 activity were decreased, Bcl-2 and p-Akt expression was up-regulated, and Bax and p-p53 expression was down-regulated by administration of rhALR. However, administration of rhALR had no effect on Fas protein expression. These results indicate that the protective effect of rhALR on renal I/R injury is associated with its anti-apoptotic action in renal tubular cells. RhALR inhibits apoptosis by increasing the ratio of Bcl-2 to Bax and by decreasing the activity of caspase-3. The activation of Akt and inactivation of p53 are involved in the rhALR anti-apoptosis process.