人参对大鼠缺血再灌注后心肌细胞凋亡的抑制作用

背景：心肌细胞凋亡与缺血再灌注损伤直接相关，心肌细胞凋亡数的多寡可以作为判断再灌注损伤程度的指标之一。人参及其提取物人参皂甙被证实能改善心肌缺血、缩小梗死面积，对缺血再灌注损伤有明显的保护作用。目的：探讨人参对大鼠心脏缺血再灌注后心肌细胞凋亡及bcl-2基因表达的作用。设计：随机对照的实验研究。地点、材料和干预：本实验在湖北省武汉市同济医院动物实验中心完成。实验共用Wistar大鼠15只，雌雄不分。Wistar鼠的左冠状动脉前降支(Left descending coronary artery,LAD)被结扎30min后再松开建立缺血再灌注心脏模型。应用原位末端标记法检测心肌凋亡细胞，并进行细胞计数；原位杂交和免疫组化检测bcl-2 mRNA和基因表达产物的蛋白质，通过图像分析系统测量阳性染色区域的平均吸光度进行量化分析，以观察人参对大鼠心肌缺血再灌心肌细胞凋亡的影响及基因表达。主要观察指标：大鼠缺血再灌注心肌细胞凋亡情况及bcl-2 mRNA，Bcl-2蛋白的表达。结果：人参治疗组bcl-2 mRNA吸光度为0．11&;#177;0．02，较单纯结扎组(0．07&;#177;0．02)和假手术组(0．06&;#177;0，01)明显升高(t=8.72，P&;lt;0．001)；人参治疗组Bcl-2蛋白吸光度为0．15&;#177;0.02，与单纯结扎组(0.09+0.02)比较，差异有非常显著性意义(t=8.631，P&;lt;0．001)，但与假手术组(0.14&;#177;0．01)比较，差异无显著性意义(P&;gt;0.05)。结论：心肌缺血再灌注可使心肌细胞凋亡数显著增加，人参治疗可明显地抑制缺血再灌注损伤诱导的心肌细胞凋亡，其机制可能是通过增强bcl-2基因表达而实现的。     

普罗布考对缺血再灌注心肌细胞凋亡的作用

背景：已发现细胞凋亡在缺血再灌注损伤中起重要作用。普罗布考除可降低血清低和高密度脂蛋白胆固醇浓度，有效治疗高胆固醇血症外，还有抗氧化活性，抑制低密度脂蛋白胆固醇的氧化修饰，减少其在血管壁沉积的作用。还有研究证明普罗布考可改善左心室功能、防止左心室扩张和减少心肌纤维化。但普罗布考保护心肌作用的确切机制尚未清楚。目的：探讨普罗布考对新西兰白兔缺血再灌注心肌细胞凋亡的作用及其可能机制；并探讨其对血清超氧化物歧化酶(serum superoxide dismuase，SOD)和丙二醛水平的影响。设计：随机对照的实验研究。地点、材料和干预：本实验在广西医科大学医学科学实验中心完成。实验选用30只雄性新西兰白兔，白兔被随机分成3组：假手术组、对照组和预治疗组，每组各10只。对照组(标准兔饲料饲养)和预治疗组(标准兔饲料饲养+普罗布考每日每只1000mg灌胃)各4周后建立缺血再灌注模型；假手术组(标准兔饲料饲养)4周后开胸用4-0号线穿过冠状动脉左前降支近端，但不予结扎。测定3组白兔心肌细胞凋亡指数、血清丙二醛、SOD水平。主要观察指标：①普罗布考对心肌细胞凋亡的影响。②普罗布考对血清SOD和丙二醛水平的影响。结果：对照组凋亡指数[(34．75&;#177;3．20)％]、血清丙二醛水平[(2．70&;#177;0．64)μmol／L]显著高于假手术组[(0．48&;#177;0．20)％，(1．06&;#177;0．46)μmol／L，q=18．42，6．29．P&;lt;0．01]。对照组血清SOD水平显著低于假手术组(q=8．78．P&;lt;0．01)。预治疗组凋亡指数和血清丙二醛水平明显低于对照组(q=9．17，4．68．P&;lt;0．01)；血清SOD水平高于与对照组(q=3．02，P&;lt;0．05)。结论：普罗布考降低缺血再灌注心肌细胞凋亡，这一保护作用可能部分是通过减少血清丙二醛水平和提高血清SOD水平来实现的。     

缝隙连接传递伤害性信号促进小鼠肝缺血再灌注损伤及细胞凋亡

目的探讨细胞缝隙连接(GJ)信号传递对肝缺血再灌注损伤(HIRI)及细胞凋亡的影响。方法 C57BL/6小鼠建立HIRI模型,随机分为假手术组(Sham组)、HIRI组、HIRI+2-氨基乙基联苯基硼酸酯(2APB)组、HIRI+维甲酸(RA)组。HIRI+2APB组及HIRI+RA组在造模前腹腔注射2APB或RA。采用HE染色观察肝组织病理损伤情况,生化检测血清ALT和AST评估肝功能情况,蛋白免疫印迹法检测凋亡相关蛋白Bim、Bax、Caspase-3的表达,TUNEL法检测肝组织细胞凋亡情况。结果与HIRI组相比,HIRI+RA组肝损伤及凋亡明显增加,Bim介导的凋亡蛋白表达增强(P均<0.05);相反,HIRI+2APB组可显著减轻肝损伤及细胞凋亡,并减少Bim介导的凋亡蛋白表达(P均<0.05)。结论 GJ传递伤害性信号可能在HIRI进展中发挥重要作用。     

缺血再灌注损伤诱导大鼠心肌细胞凋亡的实验研究

目的：探讨大鼠心肌缺血再灌注后不同时相心肌细胞凋亡情况及其与缺血再灌注的关系，并进一步探讨心肌细胞凋亡在心肌缺血再灌注损伤中的可能作用。方法：64只SD大鼠随机分为5组：对照组（假手术45min、105min、165min、225min，各时间点n=8），心肌缺血45min组（I15min,n=8），心肌缺血45min后再灌注1h、2h、3h组（I／R1h、I／R2h、I／R3h，各时间点n=8），分别在各时点处死大鼠取材。应用DNA琼脂糖凝胶电泳分析与透射电镜的检测心肌细胞凋亡的改变。结果：DNA琼脂糖电泳分析显示，I／R2h组、I／R3h组出现凋亡特征性“梯状电泳带”而对照组、L45min组及I／R1h组均未见凋亡带谱。透射电镜检测显示，对照组、L45min组、I／R1h组均未见到凋亡的心肌细胞，I／R2h组、I／R3h组心肌细胞染色质凝聚、边集、核膜完整，显示出典型的凋亡特征。结论：心肌缺血再灌注可导致心肌细胞凋亡，心肌细胞凋亡因缺血再灌注不同时相而变化；心肌细胞凋亡在大鼠心肌缺血再灌注损伤的病理生理过程中起重要作用；大鼠心肌缺血后再灌注可促发或加速心肌细胞凋亡。     

生长激素对大鼠心肌缺血再灌注后心肌细胞凋亡的作用

目的：研究生长激素对大鼠心肌缺血再灌注(myocardial ischemia reperfusion，MIR)后心肌细胞凋亡及其机制的影响。方法：24只大鼠随机分为3组，假手术组(仅手术24h)、MIR组、生长激素组，每组8只。后两组均缺血30min，再灌注24h，其中生长激素组的每只大鼠每天皮下肌注生长激素1U／kg，连续7d。前两组每只大鼠相应皮下肌注生理盐水0.5mL／d。以TUNEL法检测心肌细胞凋亡情况，DAB免疫组化法检测心肌细胞核NF-κB蛋白、心肌细胞胰岛素样生长因子-1(insulin-like growth factor-1，IGF-1)的表达并进行心肌组织病理学检查。结果：大鼠MIR 24h后心肌细胞凋亡指数明显上升[MIR组(16．17&;#177;5．02)％，假手术组为0](t=9．1ll，P&;lt;0.05)。心肌细胞核NF-κB蛋白表达呈阳性染色指数(positive index，PI)明显升高[Mill组(18.60&;#177;7．21)％，假手术组为0](t=7.297，P&;lt;0，05)。心肌病理检查见心肌缺血区呈大小不一的坏死孔灶，缺血心肌间有炎症细胞浸润，心肌排列不整齐(HE染色)，而生长激素组心肌细胞凋亡率及心肌细胞核NF-κB蛋白PI明显好于MIR组(t=4．302，2．943，P&;lt;0．05)。生长激素组IGF-1着色强度明显高于另外两组(x^2=12．443，9．167，P&;lt;0．05)，心肌细胞间炎症细胞也明显减少，坏死灶也少于MIR组。结论：生长激素可以减少MIR后心肌细胞凋亡及细胞核NF-κB染色PI，提高心肌细胞IGF-1着色强度。说明生长激素对缺血再灌注后的心肌具有保护作用。     

高压氧预处理对缺血-再灌注诱导糖尿病大鼠心肌细胞凋亡的影响

目的 探讨高压氧预处理对糖尿病大鼠心肌细胞凋亡的影响.方法 雄性Wistar大鼠45只,糖尿病造模成功后随机分为糖尿病对照组、糖尿病缺血-再灌注组、糖尿病高压氧预处理组,检测心肌凋亡及心肌Bax、Bcl-2蛋白表达.结果 与糖尿病缺血-再灌注组比较,糖尿病高压氧预处理组凋亡指数、Bcl-2蛋白灰度显著降低[(52.73±6.71)%vs(41.69±5.79)%,(183.33±9.15)vs(166.00±10.53),P<0.05],Bax蛋白灰度显著升高[(134.00±4.73)vs(141.17±6.77),P<0.05].结论 高压氧预处理有减少糖尿病大鼠心肌细胞凋亡的作用,其机制可能与下调Bax蛋白的表达,上调Bcl-2蛋白表达有关.     

缺血后处理对大鼠缺血再灌注心肌细胞凋亡的影响

目的:观察缺血后处理对大鼠缺血再灌注心肌细胞凋亡的影响。方法:实验于2006-02/05在首都医科大学附属朝阳医院心脏中心实验室完成。选择健康SD大鼠48只,随机数字表法分为3组:假手术组、缺血再灌注组和缺血后处理组,每组16只。制备大鼠心肌缺血再灌注模型。缺血再灌注组,收紧结扎线缺血40min,放松结扎线再灌注240min;缺血后处理组,缺血40min后,再灌注10s,缺血10s,连续3个循环,然后再灌注239min;假手术组,开胸后穿线做套环,但不收紧结扎线。采用TUNEL技术检测心肌细胞凋亡率,同时测定血清肌酸激酶活性和心肌梗死范围。结果:纳入动物48只,均进入结果分析。①血清中肌酸激酶活性的测定:再灌注结束后缺血后处理组和缺血再灌注组肌酸激酶活性明显高于假手术组[分别为(13.54±1.50),(20.72±1.58),(2.90±0.28)μkat/L,P<0.01],缺血后处理组明显低于缺血再灌注组(P<0.01)。②心肌梗死范围:再灌注结束后缺血后处理组和缺血再灌注组心肌缺血区与左室面积比值无明显差异,缺血后处理组心肌坏死区与缺血区比值显著低于缺血再灌注组(分别为26.1±6.7,40.2±7.2,P<0.01)。③心肌凋亡细胞计数:再灌注结束后假手术组未见明显细胞凋亡(<5%),缺血后处理组心肌细胞凋亡率明显低于缺血再灌注组[分别为(12.5±2.9)%,(21.3±3.8)%,P<0.01]。结论:缺血后处理可减轻缺血再灌注损伤、其机制可能与减少心肌细胞凋亡有关。     

缺血后处理对高血脂大鼠缺血再灌注心肌细胞凋亡的影响

目的 观察缺血后处理对高血脂大鼠缺血再灌注心肌细胞凋亡的影响.方法 选择高血脂SD大鼠48只,随机分为假手术组、缺血再灌注组和缺血后处理组,每组16只.制备大鼠心肌缺血再灌注模型.缺血再灌注组收紧结扎线缺血40 min,放松结扎线再灌注240 min;缺血后处理组缺血40 min后,再灌注10 s,再缺血10 s,连续3个循环,然后再灌注240 min;假手术组不收紧结扎线.再灌注结束后自右颈动脉分别采血测定血清肌酸激酶活性,用伊文氏兰-红四氮唑(TTC)染色和TUNEL法分别检测再灌注心肌坏死和凋亡程度.结果 再灌注结束后,肌酸激酶活性缺血后处理组和缺血再灌注组分别为(734.86±25.48)U/L和(967.64±28.16)U/L,高于假手术组的(274.28±16.94)U/L,(P<0.05),缺血后处理组低于缺血再灌注组(P<0.05);缺血后处理组心肌缺血区与左心室面积比值与缺血再灌注组无显著性差异,但心肌坏死区与缺血区比值为(24.8±6.7)%,低于缺血再灌注组的(38.2±7.1)%(P<0.05);假手术组未见明显细胞凋亡,缺血后处理组心肌细胞凋亡率为(12.7±2.8)%,低于缺血再灌注组的(20.9±3.7)%(P<0.05).结论 缺血后处理可减轻高血脂大鼠心肌缺血再灌注损伤,机制可能与减少心肌细胞凋亡有关.     

高、低剂量参麦注射液对缺血／再灌注心肌保护作用的对比研究-参麦注射液抑制心肌细胞凋亡的关键作用

目的：观察参麦注射液对家兔急性心肌缺血／再灌注心脏功能和心肌细胞死亡的影响，并初步探讨其中的主要机制。方法：采用流式细胞仪和原位缺口末端标记法（TUNEL）检测凋亡。结果：两种剂量GSK有心肌保护作用，并且有显著差异，高剂GSK心肌保护作用显著强于低剂量GSK。结论：参麦注射液有抗心肌细胞凋亡作用。     

超声微泡介导尼卡地平对大鼠缺血再灌注心肌细胞凋亡及相关基因表达的影响

目的探讨超声破坏微泡介导尼卡地平对大鼠急性缺血再灌注心肌细胞凋亡及相关基因Bcl-2,Bax表达的影响。方法60只SD大鼠随机分空白对照、假手术、缺血再灌注、尼卡地平、超声微泡、超声微泡介导尼卡地平六组。阻断左冠状动脉前降支40min,再灌注120min,建立在体急性心肌缺血再灌注模型。TUNEL法检测凋亡心肌细胞,SABC免疫组化法检测Bcl-2、Bax基因表达。结果缺血再灌注诱导心肌细胞凋亡,尼卡地平可减少其发生,上调Bcl-2基因表达,下调Bax基因表达,超声微泡介导可进一步减少凋亡发生。结论尼卡地平可上调Bcl-2并下调Bax基因表达,升高Bcl-2/Bax比值,显著减少缺血再灌注诱导心肌细胞凋亡,通过超声微泡介导,可增强尼卡地平抗凋亡作用。     

Role of tumor necrosis factor-alpha in myocardial dysfunction and apoptosis during hindlimb ischemia and reperfusion

OBJECTIVE: Peripheral vascular surgery involving limb ischemia/reperfusion is associated with tumor necrosis factor-alpha production and an increased risk of cardiac complications. The objective of this study was to investigate the role of tumor necrosis factor-alpha in myocardial apoptosis and dysfunction following hindlimb ischemia/reperfusion. DESIGN: Randomized perspective animal study. SETTING: Research laboratory. SUBJECTS: Adults male tumor necrosis factor-alpha(-/-) and littermate wild-type mice. INTERVENTIONS: Bilateral hindlimb ischemia/reperfusion was induced in wild-type and tumor necrosis factor-alpha(-/-) mice using tourniquet occlusion. After 2 hrs of hindlimb ischemia, the tourniquets were released, allowing reperfusion for 0.5-24 hrs. MEASUREMENTS AND MAIN RESULTS: In wild-type mice, hindlimb ischemia/reperfusion resulted in myocardial depression early during the reperfusion period (p < .05). These effects were temporally correlated with enhanced levels of myocardial and plasma tumor necrosis factor-alpha. All variables were restored to baseline levels by 24 hrs of reperfusion. Myocardial apoptosis, assessed by cell death enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick-end labeling staining, and caspase-3 activity, was also significantly higher at 6 hrs of reperfusion (p < .05) but returned to baseline levels by 24 hrs. Interestingly, cardiac dysfunction and myocardial apoptosis were abolished in tumor necrosis factor-alpha mice subjected to the same degree of hindlimb ischemia/reperfusion as the wild-type mice. Treatment of etanercept restored cardiac function in wild-type mice. CONCLUSIONS: Tumor necrosis factor-alpha contributes significantly to myocardial dysfunction and apoptosis in hindlimb ischemia/reperfusion. Although a causal link between myocardial apoptosis and cardiac dysfunction is not established, our study does suggest that tumor necrosis factor-alpha may be a potential therapeutic target for cardiac injury in clinical situations involving prolonged remote ischemia/reperfusion.     

Glucagon increases gap junctional intercellular communication via cAMP in the isolated perfused rat liver

The effects of glucagon on the subacinar distribution of hepatic transmembrane potentials were studied in the perfused fasted rat liver. The livers were perfused with a Krebs-Henseleit buffer, and membrane potentials of matched periportal and pericentral hepatocytes were determined using glass microelectrodes. Lactate- and pyruvate-induced glucose production and O2 uptake were potentiated by 10(-8) M glucagon. Twenty-five micromoles 8-bromoadenosine 3',5'cyclic monophosphate (8-BrcAMP) exhibited stimulatory effects similar, in terms of glucose production and O2 uptake to those of glucagon. Octanol (0.1 and 0.5 mM) had no effect on glucose production but reversibly increased O2 uptake by 16% to 30% over all experiments. Under basal conditions (no exogenous substrate) hepatocyte membrane potentials averaged approximately -27 mV, and no gradients were found between periportal and pericentral hepatocytes. Addition of lactate and pyruvate produced hyperpolarization in all hepatocytes. However, there was a small but statistically significant gradient produced across the hepatic acinus in membrane potential, i.e., the hyperpolarization was higher in the periportal region compared with the pericentral region. Glucagon and 8-BrcAMP induced marked hyperpolarization in periportal and pericentral hepatocytes with no gradients across the acinus. Although no changes were found under basal and lactate plus pyruvate, 0.5 mM octanol induced heterogeneity of membrane potential during glucagon and 8-BrcAMP stimulation. Our findings suggest that glucagon-induced homogeneity of membrane potential may be mediated by increased gap junctional coupling. In addition, cAMP may be responsible for the increase in the intercellular communication during glucagon stimulation.     

肿瘤坏死因子-α在大鼠脑缺血再灌注中的表达及对神经细胞凋亡的影响

目的:观察大鼠脑缺血再灌注损伤后肿瘤坏死因子-α(tumornecrosisfactor-alpha,TNF-α)表达及细胞凋亡情况,探讨TNF-α在脑缺血再灌注损伤中的作用。方法:采用大鼠局灶性脑缺血再灌注损伤模型,分为3组:脑缺血再灌注组大鼠大脑中动脉阻塞2h,再灌注2,6,12,24,48,72,96h、假手术组及永久缺血组,分别测定TNF-α表达(用免疫组织化学法)及细胞凋亡数(原位凋亡检测试剂盒)。结果:脑缺血再灌注组TNF-α表达水平犤6h:(15.0±3.21)个/mm2,12h:(47.0±0.87)个/mm2,24h:(49.0±10.3)个/mm2,48h:(44.8±6.9)个/mm2,96h:(37.9±6.4)个/mm2犦、细胞凋亡数犤2h:(33.3±0.8)个/mm2,6h:(56.6±1.6)个/mm2,12h:(72.3±4.2)个/mm2,24h:(86.6±5.5)个/mm2,48h:(96.8±0.9)个/mm2犦明显高于假手术组(P<0.01)及永久缺血组(P<0.05);且TNF-α表达与细胞凋亡数关系密切(r=0.567,P<0.01)。结论:大鼠脑缺血再灌注损伤后TNF-α在神经元迟发性坏死中起着重要作用。     

生长激素对大鼠心肌缺血再灌注后心肌细胞凋亡的作用

目的:研究生长激素对大鼠心肌缺血再灌注(myocardialischemiareper-fusion,MIR)后心肌细胞凋亡及其机制的影响。方法:24只大鼠随机分为3组,假手术组(仅手术24h)、MIR组、生长激素组,每组8只。后两组均缺血30min,再灌注24h,其中生长激素组的每只大鼠每天皮下肌注生长激素1U/kg,连续7d。前两组每只大鼠相应皮下肌注生理盐水0.5mL/d。以TUNEL法检测心肌细胞凋亡情况,DAB免疫组化法检测心肌细胞核NF-κB蛋白、心肌细胞胰岛素样生长因子-1(insulin-likegrowthfactor-1,IGF-1)的表达并进行心肌组织病理学检查。结果:大鼠MIR24h后心肌细胞凋亡指数明显上升犤MIR组(16.17±5.02)%,假手术组为0犦(t=9.111,P<0.05)。心肌细胞核NF-κB蛋白表达呈阳性染色指数(positiveindex,PI)明显升高犤MIR组(18.60±7.21)%,假手术组为0犦(t=7.297,P<0.05)。心肌病理检查见心肌缺血区呈大小不一的坏死孔灶,缺血心肌间有炎症细胞浸润,心肌排列不整齐(HE染色),而生长激素组心肌细胞凋亡率及心肌细胞核NF-κB蛋白PI明显好于MIR组(t=4.302,2.943,P<0.05)。生长激素组IGF-1着色强度明显高于另外两组(χ2=12.443,9.167,P<0.05),心肌细胞间炎症细胞也明显减少,坏死灶也少于MIR组。结论:生长激素可以减少MIR后心肌细胞凋亡及细胞核NF-κB     

缝隙连接通讯对创伤失血性休克自由基代谢和炎症因子释放的影响

目的探讨缝隙连接通讯对创伤失血性休克自由基代谢和炎症因子的影响。方法采取钳夹一侧股骨中段致其粉碎性骨折合并股动脉放血的方式制备新西兰兔创伤失血性休克模型。将制成模型的24只新西兰大白兔随机分为三组(n=8):创伤休克组(Ⅰ组),创伤休克复苏组(Ⅱ组)和创伤阻断组(Ⅲ组)。模拟救援过程,将各动物模型分为创伤期、休克期、复苏期和观察期。监测收缩压、舒张压、平均动脉压、心率、呼吸等生理指标,并记录各时点的数值。在各个时点抽取兔血,离心,取上清检测肿瘤坏死因子-α(TNF-α)、白细胞介素-1(IL-1)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)等炎症因子(ELISA法);同时检测丙二醛(MDA)、超氧化物歧化酶(SOD)等自由基代谢指标。结果创伤失血性休克后血液回输复苏可显著减少促炎因子TNF-α、IL-1、IL-6的释放(P<0.05),显著增加抗炎因子IL-10的释放(P<0.05);缝隙连接通讯早期阻断后,可减少创伤休克期TNF-α、IL-6等部分促炎因子的产生释放而较基础值无显著变化,对IL-10等抗炎因子与Ⅱ组比较无显著影响(P>0.05)。同时,血液回输也可显著减少自由基过氧化反应指标MDA的产生释放(P<0.05),增加因创伤休克而降低的抗氧化酶SOD的产生释放(P<0.05);缝隙连接通讯早期阻断后,可减少创伤休克期MDA的产生释放而较基础值无显著变化,对抗氧化酶SOD与Ⅱ组比较无显著影响(P>0.05)。结论在创伤失血性休克早期阻断缝隙连接通讯,可减少部分促炎因子的产生释放和自由基的过氧化反应,而对抗炎因子和抗氧化酶无显著作用。     

筛选心肌缺血再灌注大鼠差异表达基因

目的：利用抑制性消减杂交技术，筛选出大鼠心肌缺血再灌注的差异表达基因，以期通过基因线索探讨其损伤机制。方法：实验于2006—03／10在中山大学中山医学院完成。①实验分组：Sprague-Dawley雄性大鼠40只，随机分为手术组，对照组，每组20只。②实验干预：手术组结扎左冠状动脉，心电图出现急性心肌梗死改变90min后，去除结扎线，再灌注60min，建立心肌缺血再灌注大鼠模型。对照组仅穿线不结扎，余同手术组。③取缺血区心肌，提取Total RNA，构建cDNA文库，利用抑制性消减杂交技术筛选差异表达基因，测序，登录Genbank寻找同源性基因。结果：共获得124个阳性结果，56个为高表达基因，68个为低表达基因，其中发现5个新的cDNA片段。其中能量代谢、物质运输、信号转导相关差异表达基因分别占所有差异表达基因的39．25％，15．89％，15．89％，并且主要变化为下调。结论：抑制性消减杂交技术是一种高效的筛选差异基因的方法。心肌缺血再灌注后基因变化涉及多种功能的基因，以能量代谢、物质运输、信号转导相关基因下调明显。     

Inhibitors of bradykinin-inactivating enzymes decrease myocardial ischemia/reperfusion injury following 3 and 7 days of reperfusion

Inhibitors of bradykinin (BK)-inactivating enzymes protect from myocardial ischemia/reperfusion injury after short periods of reperfusion. However, protection after 2 to 3 h of reperfusion does not mean that myocardium remains viable for an extended time. Therefore, we examined the effects of inhibitors of angiotensin-converting enzyme (ramiprilat), EP24.11 (cFP-F-pAB), and EP24.15 (cFP-AAF-pAB) in a chronic model of myocardial ischemia/reperfusion injury. A left descending coronary artery was occluded for 30 min in anesthetized rabbits. Saline, ramiprilat, or endopeptidase inhibitors were given after 27 min of occlusion. The BK(2) receptor antagonist HOE140 was administered in certain experiments. After ischemia, the occlusion was released, and the animal allowed to recover for 3 or 7 days. Surgery was then repeated, and the heart removed for determination of infarct size. In separate experiments, the heart was removed after 2 h of reperfusion for determination of BK tissue levels. Ramiprilat and endopeptidase inhibitors reduced infarct size at 3 and 7 days. Combining inhibitors further reduced infarct size after 3 days. The protective effect of the endopeptidase inhibitors was blocked by HOE140. Infarct sizes at 7 days were larger than at 3 days. The additive effect of multiple inhibitors was absent at 7 days. Ramiprilat and cFP-F-pAB significantly increased tissue BK levels. We conclude that inhibition of BK-inactivating enzymes protects endogenous BK from degradation and provides long-lasting protection from myocardial ischemia/reperfusion injury. A single treatment at the time of reperfusion does not prevent extension of the infarction between 3 and 7 days.     

Effects of Aloe vera on gap junctional intercellular communication and proliferation of human diabetic and nondiabetic skin fibroblasts

OBJECTIVE: To evaluate the effects of Aloe vera on gap junctional intercellular communication (GJIC) and proliferation of human skin fibroblasts in the presence or absence of basic fibroblast growth factor (FGF-2). DESIGN: In vitro study using human type II diabetic and nondiabetic skin fibroblast cell lines. SETTING AND SUBJECTS: Diabetic (n = 4) and nondiabetic (n = 4) human skin fibroblast cell lines were purchased from Coriell Institute for Medical Research (Camden, NJ). The cells were cultured with or without Aloe vera extract in increasing concentrations (0%, 0.625%, 1.25%, 2.5%, 5%, 10%, and 20%; v/v) in culture medium and with or without FGF-2 (30 ng/mL). MEASUREMENTS: GJIC was evaluated after 48-hour incubation with treatments by laser cytometry. Cells were counted after 72-hour incubation with treatments by using a Coulter counter. RESULTS: The rate of GJIC was greater (p < 0.01) for diabetic than for nondiabetic fibroblasts (3.5 +/- 0.1 versus 3.0 +/- 0.1% per minute during the first 4 minutes after photobleaching). GJIC was increased ( p < 0.05) for diabetic fibroblasts in the presence of 2.5% and 5% of Aloe vera extract (4.2 +/- 0.1 and 4.0 +/- 0.2 versus 3.5 +/- 0.1% per minute for control, respectively). FGF-2 stimulated (p < 0.01) GJIC for diabetic (4.0 +/- 0.1 versus 3.5 +/- 0.1% per minute for control) and nondiabetic (3.5 +/- 0.1 versus 3.0 +/- 0.1% per minute for control) fibroblasts. Aloe vera extract did not affect GJIC of nondiabetic fibroblast cultured without FGF-2. However, Aloe vera extract decreased (p < 0.05) FGF-2 stimulatory effects on GJIC of diabetic and nondiabetic fibroblasts. Proliferation of diabetic fibroblasts was increased (p < 0.05) by 1.25% and 2.5% Aloe vera extract in medium. Proliferation of nondiabetic fibroblasts was not affected by Aloe vera extract. FGF-2 increased (p < 0.05) proliferation of nondiabetic fibroblasts and FGF-2 did not affect proliferation of diabetic fibroblasts. Aloe vera extract decreased (p < 0.05) FGF-2 stimulatory effects on proliferation of nondiabetic fibroblasts. CONCLUSIONS: These data demonstrate that Aloe vera has the ability to stimulate GJIC and proliferation of human skin fibroblasts in diabetes mellitus. Furthermore, these results indicate that Aloe vera contains a compound(s) that neutralizes, binds with FGF-2 receptor, or otherwise alters signaling pathways for FGF-2. By affecting both GJIC and proliferation of diabetic fibroblasts, Aloe vera may improve wound healing in diabetes mellitus.     

胰岛素对缺血再灌注心肌超微结构和细胞凋亡的影响

目的:探讨极化液(胰岛素)对家兔心肌缺血再灌注损伤的保护作用。方法:选择健康雄性家兔48只,按随机抽签法分为3组:对照组,胰岛素组,葡萄糖-钾-胰岛素(glucose-insulin-potassium,GIK)组,每组16只。制备兔心肌缺血再灌注损伤模型,分别用GIK、胰岛素、生理盐水干预分组。再灌注结束后检测心肌梗死面积,在电镜下观察心肌细胞的超微结构,原位末端标记(TUNEL)法测定凋亡心肌细胞,免疫组化SP法测定原癌基因蛋白(Bcl-2),Fas的含量。结果:与对照组比较,GIK及胰岛素组家兔心肌细胞超微结构表现为损伤减轻,心肌梗死面积明显减少犤GIK组(38.9±4.33)%,胰岛素组(40.8±5.22)%,对照组(54.42±4.27)%犦(q=4.32,3.95,P<0.05),凋亡指数犤GIK组(1.38±0.82),胰岛素组(1.28±0.54),对照组(2.15±0.19)犦(q=0.65,0.72,P<0.05)和Fas含量显著减少(q=0.07,0.06,P<0.05),Bcl-2含量增加(q=0.14,0.11,P<0.05)。GIK组和胰岛素组心肌细胞凋亡指数及Fas,Bcl-2蛋白含量比较,差异无显著性意义(P>0.05)。结论:GIK具有抗缺血再灌注损伤的作用,其机制可能是通过胰岛素调节Bcl-2和Fas介导的心肌缺血再灌注细胞凋亡而实现。     

间隙连接通讯功能对小剂量甲状旁腺激素成骨效应调控的机制

INTRODUCTIONBoneformativeprocessesinducedbyintermittenttreatmentoflow－doseparathyroidhormones（PTH）possessnovelandhopefullytherapeuticeffectsonosteoporosis[１－２]．Theimportantsignaltrans－ductionsandmechanismsmediatedbygapjunctionalintercellularcommunication（GJIC）viagapjunctions（GJ）composedofConnex－in４３（Cx４３）betweenadjacentosteoblastsisconceivedtoplaycru－cialrolesintheseprocesses[３－４]．Whereas，theessentialcontributionsofGJICtolow－dosePTHassociatedboneformationa…