缝隙连接蛋白43在老年大鼠缺血性室性心律失常中的作用

Objective To investigate the expression of connexin43 ( Cx43 ) and effect of vagal nerve stimulation (VNS) on ventricular tachyarrhythmias during acute myocardial ischemia( MI )in aged rats. Methods Male Sprague-Dawley rats[Adult group ( ≤ 4 months) and Aged group ( ≥24 months)]:MI (n = 15 ):ligated left anterior descending coronary for 30 minutes; MI-vagal nerve stimulation(VNS) ( n = 15 ); MI-VNS-atropine (0. 5 mg/kg, n = 13 ); MI-VNS-carbenoxolone ( 10 mg/kg, n = 11 ); sham operation (SO, n = 10):without coronary ligation. Ventricular arrhythmias were monitored by an electrocardiogram. Cx43 protein expression was analyzed by Western blot. Results During the 30 minutes ligation,incidences of ventricular tachycardia (VT) and ventricular fibrillation(VF) in aged rats increased significantly compared to those of adult rats ( P ＜ 0. 05 ). VNS did not affect the occurrence of VT and VF ( both P ＞ 0.05 ); however, VNS suppressed the occurrence of irreversible VF ( P ＜ 0. 05 ); both atropine and carbenoxolone ( a gap junction inhibitor) could abolish the effect of VNS on ischemia-induced irreversible VF ( both P ＜0. 05). Ischemia did not result in changes of total Cx43 amount in adult and aged rats compared to that of SO group,respectively. The amount of nonphosphorylated Cx43 was increased markedly in adult and aged rats compared to that of SO group,respectively.Cx43 dephosphorylation induced by ischemia was significantly suppressed by VNS in adult and aged rats( P ＜0. 05 ). However,the amount of total Cx43 of SO group in aged rats was significantly decreased by 50% compared to that of SO group in adult rats ( P ＜ 0. 05 ). Conclusion The present study suggested that the incidence of ischemia-induced ventricular tachyarrhythmias increased markedly and the anti-arrhythmic effect of VNS was decreased significantly in aged rats, which may be associated with reduction of Cx43 protein of ventricle in aged rats.     

缝隙连接蛋白43在老年大鼠缺血性室性心律失常中的作用

Objective To investigate the expression of connexin43 ( Cx43 ) and effect of vagal nerve stimulation (VNS) on ventricular tachyarrhythmias during acute myocardial ischemia( MI )in aged rats. Methods Male Sprague-Dawley rats[Adult group ( ≤ 4 months) and Aged group ( ≥24 months)]:MI (n = 15 ):ligated left anterior descending coronary for 30 minutes; MI-vagal nerve stimulation(VNS) ( n = 15 ); MI-VNS-atropine (0. 5 mg/kg, n = 13 ); MI-VNS-carbenoxolone ( 10 mg/kg, n = 11 ); sham operation (SO, n = 10):without coronary ligation. Ventricular arrhythmias were monitored by an electrocardiogram. Cx43 protein expression was analyzed by Western blot. Results During the 30 minutes ligation,incidences of ventricular tachycardia (VT) and ventricular fibrillation(VF) in aged rats increased significantly compared to those of adult rats ( P ＜ 0. 05 ). VNS did not affect the occurrence of VT and VF ( both P ＞ 0.05 ); however, VNS suppressed the occurrence of irreversible VF ( P ＜ 0. 05 ); both atropine and carbenoxolone ( a gap junction inhibitor) could abolish the effect of VNS on ischemia-induced irreversible VF ( both P ＜0. 05). Ischemia did not result in changes of total Cx43 amount in adult and aged rats compared to that of SO group,respectively. The amount of nonphosphorylated Cx43 was increased markedly in adult and aged rats compared to that of SO group,respectively.Cx43 dephosphorylation induced by ischemia was significantly suppressed by VNS in adult and aged rats( P ＜0. 05 ). However,the amount of total Cx43 of SO group in aged rats was significantly decreased by 50% compared to that of SO group in adult rats ( P ＜ 0. 05 ). Conclusion The present study suggested that the incidence of ischemia-induced ventricular tachyarrhythmias increased markedly and the anti-arrhythmic effect of VNS was decreased significantly in aged rats, which may be associated with reduction of Cx43 protein of ventricle in aged rats.     

Effect of endogenous insulin-like growth factor and stem cell factor on diabetic colonic dysmotility

AIM: To investigate whether the reduction of stem cell factor (SCF) is mediated by decreased endogenous insulin-like growth factor (IGF)-1 in diabetic rat colon smooth muscle. METHODS: Sixteen Sprague-Dawley rats were randomly divided into two groups: control group and streptozotocin-induced diabetic group. After 8 wk of streptozotocin administration, colonic motility function and contractility of circular muscle strips were measured. The expression of endogenous IGF-1 and SCF was tested in colonic tissues. Colonic smooth muscle cells were cultured from normal adult rats. IGF-1 siRNA transfection was used to investigate whether SCF expression was affected by endogenous IGF-1 expression in smooth muscle cells, and IGF-1 induced SCF expression effects were studied. The effect of high glucose on the expression of endogenous IGF-1 and SCF was also investigated. RESULTS: Diabetic rats showed prolonged colonic transit time (252 ± 16 min vs 168 ± 9 min, P < 0.01) and weakness of circular muscle contraction (0.81 ± 0.09 g vs 2.48 ± 0.23 g, P < 0.01) compared with the control group. Endogenous IGF-1 and SCF protein expression was significantly reduced in the diabetic colonic muscle tissues. IGF-1 and SCF mRNA expression also showed a paralleled reduction in diabetic rats. In the IGF-1 siRNA transfected smooth muscle cells, SCF mRNA and protein expression was significantly decreased. IGF-1 could induce SCF expression in a concentration and time-dependent manner, mainly through the extracellular-signal-regulated kinase 1/2 signal pathway. High glucose inhibited endogenous IGF-1 and SCF expression and the addition of IGF-1 to the medium reversed the SCF expression. CONCLUSION: Myopathy may resolve in colonic motility dysfunction in diabetic rats. Deficiency of endogenous IGF-1 in colonic smooth muscle cells leads to reduction of SCF expression.     

普罗布考对2型糖尿病大鼠肾脏硫氧还蛋白系统表达的影响

目的 观察硫氧还蛋白系统在2型糖尿病大鼠肾脏组织的表达及早期普罗布考干预对硫氧还蛋白系统表达的影响.方法 将30只雄性SD大鼠分为正常对照组(C组)、糖尿病组(D组)、糖尿病普罗布考治疗组(P组),普罗布考干预8周后,通过免疫组化、RT-PCR、Western免疫印迹技术观察普罗布考对硫氧还蛋白(Thioredoxin,Trx)及硫氧还蛋白相互作用蛋白(Thioredoxin-interacting protein,Txnip)表达的影响,并检测各组大鼠空腹血糖(FPG)、胰岛素、肾功能、丙二醛、超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化氢酶(Catalase,CAT)的含量.结果 P组与C组比较,Trx表达明显降低(0.162±0.008对0.239±0.006,P＜0.05),Txnip表达明显升高(0.159±0.003对0.091±0.016,P＜0.05).P组与D组比较,Trx表达升高(0.162±0.008对0.108±0.013,P＜0.05),Txnip表达降低(0.159±0.003对0.236±0.009,P＜0.05).与C组比较,D组大鼠氧化应激指标升高、肾功能受损、抗氧化酶降低,而P组大鼠上述指标(除FPG外)有所改善(P＜0.05).结论 普罗布考通过部分恢复Trx功能,降低Txnip表达,减少氧化应激,发挥对2型糖尿病大鼠肾脏组织的保护作用.

Abstract：

Objective To observe the expression of thioredoxin (Trx) and thioredoxin-interacting protein (Txnip) in the kidney of type 2 diabetic rats induced by streptozotocin and the effect of probucol treatment on thioredoxin system. Methods Thirty male SD rats were divided into control group( C, n = 10), diabetes group ( D, n =10), and probucol treated diabetic group ( P, n = 10). After eight weeks of probucol treatment, the expressions of Trx and Txnip in the kidney of three groups were measured by RT-PCR, Western blot, and immunohistochemistry. Body weight,24 h microalbuminuria( ALB), fasting plasma glucose( FPG), fasting insulin( HNS), blood urea nitrogen (BUN), creatinine (Cr), malondialdehyde ( MDA ), superoxide dismutase ( SOD ), and catalase (CAT) were determined. Results Compared with group C, Trx was markedly decreased in group P (0. 162 ±0. 008 vs 0. 239 ±0. 006, P＜0.05 ), while Txnip was significantly increased (0. 159±0.003 vs 0. 091 ±0.016, P＜0.05 ). Trx in group P was increased as compared with group D (0. 162 ±0. 008 vs 0. 108 ± 0. 013, P ＜ 0. 05 ), while Txnip was lowered (0. 159±0.003 vs 0. 236±0.009 ,P＜0.05 ). FPG, 24 h ALB, BUN, Cr,and MDA levels in group D were markedly increased as compared with group C (P＜0. 05), while the activity of SOD, CAT, and FINS levels were decreased apparently (P＜0.05). The above markers except for FPG in group P were ameliorated (P＜0. 05 ).Conclusions Probucol attenuated oxidative stress by means of partially restoring Trx function and reducing Txnip expression, and thus played a major role in renoprotection of type 2 diabetic nephropathy.     

丁基苯酞对血管性痴呆大鼠记忆及海马Bcl-2、Bax的影响

目的 研究丁基苯酞(NBP)对血管性痴呆(VD)大鼠记忆、海马病理变化及抗凋亡蛋白(Bcl-2)和促凋亡蛋白(Bax)蛋白表达的影响.方法 采用永久性结扎双侧颈总动脉方法制备VD大鼠模型.SD大鼠被随机分成假手术组、VD模型组、NBP治疗组、尼莫地平治疗组.应用Morris水迷宫检测大鼠记忆能力,苏术精-伊红(HE)染色观察海马神经元形态,免疫组化检测海马Bcl-2和Bax的表达.结果 VD模型组与假手术组大鼠比较记忆能力显著下降,逃避潜伏期分别为(78.79±21.93) s与(16.96±7.44) s (P＜0.05),海马神经元病理改变严重,免疫阳性细胞数量显著增加,其中Bax变化更为显著 (43.00±6.72与6.00±1.29,P＜0.05),Bcl-2与Bax的比值较对照组明显降低;NBP治疗组与模型组比较记忆能力显著改善,逃避潜伏期分别为(47.13±21.75) s与(78.79±21.93) s (P＜0.05),海马神经元病理形态明显改善,Bcl-2免疫阳性细胞数显著增多(33.14±8.05与21.81±4.97,P＜0.05),Bax免疫阳性细胞数显著减少(32.93±4.99与43.00±6.72,P＜0.05).NBP治疗组与尼莫地平治疗组之间比较,各项指标均无显著差异 (P＞0.05).结论 NBP能改善VD大鼠记忆能力,抑制海马细胞凋亡,对VD大鼠有一定的治疗作用.

Abstract：

Objective To study the effects of butylphthalide (NBP) on memory and apoptosis related protein as well as neuronal pathology in hippocampus of vascular dementia (VD) rats. Methods VD model was generated by the permanent occlusion of bilateral common carotid arteries in SD rats to produce the forebran ischemia. Male SD rats were randomly allocated into sham-operation group, VD model group, NBP treatment group and nimodipine treatment group. The function of memory was tested by the Morris water maze. The neuronal pathological changes and the expression of Bcl-2 and Bax proteins in the hippocampus were observed with hematoxylin-eosin (HE) staining and immunohistochemical staining, respectively. Results The impaired memory of VD rats was proved by the lengthened mean escape latency [(78.79±21.93)vs.(16.96±7.44),P＜0.05] and the neuron in hippocampus was severely damaged. The decveased ratio of Bcl-2/Bax resulted from the overexpression of Bax proteins in VD model group versus the sham-operation group [(43.00±6.72)vs.(6.00±1.29),P＜0.05]. The treatment of NBP notably improved the memory function of VD rats and reduced the hippocampus pathological injury (P＜0.05). The expression of Bcl-2 protein raised [(33.14±8.05)vs.(21.81±4.97),P＜0.05] along with reduced expression of Bax protein [(32.93±4.99)vs.(43.00±6.72),P＜0.05] after NBP treatment. However, there was no significant difference in the treatment effects between nimodipine and NBP group (P＞0.05). Conclusions NBP treatment could improve memory of VD rats and reduce the hippocampus pathological lesion by inhibiting the apoptosis related protein.     

Effect of bone marrow mesenchymal stem cells on the Smad expression of hepatic fibrosis rats

Objective:To investigate the impact of bone marrow mesenchymal stem cells on Smad expression of hepatic fibrosis rats.Methods:A total of 48 adult female SD rats were randomly divided into three groups,normal control group(n=10),observation group(n=19)with liver fibrosis model rats injected with BMSCs cells:model group(n=19),with liver fibrosis model rats injected with physiological saline.Serum index,TGF-β1 and Smad expression were detected.Results:TypeⅢprocollagen,Ⅳcollagen,hyaluronic acid,laminin levels of observation group were significantly lower than those of model group(P0.05).The content and expression of TGF-β1in serum and liver tissue of observation group were significantly lower than those of model group(P0.05).Compared with normal control group,the Smad3,Smad4 mRNA and protein expression of model group were significantly increased,the Smad7 mRNA and protein expression were significantly reduced(P0.05).Compared with model group.Smad3,Smad4 mRNA and protein expression of observation group were significantly reduced,and Smad7 mRNA expression were significantly increased(P0.05).Conclusions:BMSCs can regulate Smad expression to some extent,and reduce the degree of liver fibrosis.     

Mechanism of Profilin-1 in regulating eNOS/NO signaling pathway and its role in hypertensive myocardial hypertension

Objective:To explore the mechanism of Profilin-1 in regulating eNOS/NO pathway and its role in the development of myocardial hypertrophy.Methods:Spontaneously hypertensive rats(SHR) aged 5 weeks were injected with different adenovirus vectors to induce Profilin-1expression knockdown(SHR-I) or over express(SHR-H) or to use as control(SHR-C).All these treatment were compared with Wistar-Kyoto rats(SKY) treated with control adenovirus vectors(WKY-C).The same injection was executed at the sixth week during the experiment of 12 weeks.After experiment,the left ventricular weight-to-heart weight ratio(LVW/HW)and left ventricular long axis(LVLA) were measured.Meanwhile.NO contents in blood and myocardium,Profilin-1,eNOS and Caveolin-3 niRNA and protein levels and phosphorylated eNOS(P-eNOS) protein level in myocardium were determined.Results:Compared with WKY-C group,the SHR-C group was statistically higher in LVW/HW(0.79±0.03).LVLA(11.82±0.58 mm) and Profilin-1 niRNA and prolein level(P0.05).but lower in NO content[(18.63±6.23) μmol/L| in blood and[(2.71±0.17) μmol/L]in myocardium).eNOS activity and Caveolin-3 expression(P0.05).The over expressing Profilin-1 led SHR-H group to a higher value of LVW/HW[(0.93±0.03) mm and LVLA(14.17±0.69) mm]in comparison with SHR-C group(P0.05).and to a lower value of NO content(in myocardium).eNOS activity and Caveolin-3 expression(P0.05):however,this phenomenon was reversed by the knockdown Profilin-1 expression(SHR-I group).Conclusions:Profilin-1 expression,being negative in regulating Caveolin-3 expression and eNOS/NO pathway activity,promotes the development of myocardial hypertrophy which can be reversed by Profilin-1 silencing.     

Effect of ischemic preconditioning on P-selectin expression in hepatocytes of rats with cirrhotic ischemia-reperfusion injury

AIM: To investigate the effects and mechanisms of ischemic preconditioning (IPC) on the ischemia/reperfusion (I/R) injury of liver cirrhosis in rats and the effect of IPC on P-selectin expression in hepatocytes.METHODS: Forty male SD rats with liver cirrhosis were randomly divided into sham operation group (SO group),ischemia/reperfusion group (I/R group), ischemic preconditioning group (IPC group), L-Arginine preconditioning group (APC group), L-NAME preconditioning group (NPC group), eight rats in each group. Hepatocellular viability was assessed by hepatic adenine nucleotide level and energy charge (EC) determined by HPLC, ALT, AST and LDH in serum measured by auto- biochemical analyzer and bile output.The expression of P-selectin in the liver tissue was analyzed by immunohistochemical technique. Leukocyte count in ischemic hepatic lobe was calculated.RESULTS: At 120 min after reperfusion, the level of ATP and EC in IPC and APC groups was higher than that in I/R group significantly. The increases in AST, ALT and LDH were prevented in IPC and APC groups. The livers produced more bile in IPC group than in I/R group during 120 min after reperfusion (0.101±0.027 versus 0.066±0.027 ml/g liver,P=0.002). There was a significant difference between APC and I/R groups, (P=0.001). The leukocyte count in liver tissues significantly increased in I/R group as compared with SO group (P＜0.05). The increase in the leukocyte count was prevented in IPC group. Administration of L-arginine resulted in the same effects as in IPC group. However,inhibition of NO synthesis (NPC group) held back the beneficial effects of preconditioning. Significant promotion of P-selectin expression in hepatocytes in the I/R group was observed compared with the SO group (P＜0.01). IPC or L-arginine attenuated P-selectin expression remarkably (P＜0.01). However, inhibition of NO synthesis enhanced Pselectin expression (P＜0.01). The degree of P-selectin expression was positively correlated with the leukocyte counts infiltrating in liver (r=0.602, P=0.000).CONCLUSION: IPC can attenuate the damage induced by I/R in cirrhotic liver and increase the ischemic tolerance of the rats with liver cirrhosis. IPC can abolish I/R induced leukocyte adhesion and infiltration by preventing postischemic P-selectin expression in the rats with liver cirrhosis via a NO-initiated pathway.     

缺血预处理对大鼠血管生长物质表达及新生动脉形成的影响

目的 观察缺血预处理(IPC)对促进血管新生的血管内皮生长因子(VEGF)、联合血小板源生长因子B(PDGF-B)和抑制血管新生的ADAMTS-1表达及对有功能的新生动脉形成的影响.方法 建立大鼠心脏IPC模型,通过免疫组织化学方法观察IPC后6、12、24 h VEGF、PDGF-B和ADAMTS-1的表达.在IPC后24 h建立大鼠心肌梗死模型,14 d后处死动物,通过免疫组织化学方法标记血管平滑肌细胞,观察IPC对心脏梗死区边缘成熟的新生小动脉形成的影响.对照组不进行缺血预处理,仅开胸手术24 h后取心脏组织行免疫组织化学检测或建立心肌梗死模型观察新生小动脉形成情况.结果 IPC后6、12、24 h,心肌的缺血区可见促进血管新生的VEGF和PDGF-B表达显著升高(P均<0.05),与对照组和非缺血区比较差异均有统计学意义,抑制血管生长的ADAMTS-1表达在各时间点亦可见显著升高(P均<0.05),且表达区域与VEGF和PDGF-B一致.IPC后心肌梗死14 d,可见梗死边缘区新生动脉数显著高于对照组(P<0.05).结论 IPC可以促进梗死边缘区成熟的新生动脉的形成,促血管生长的VEGF、PDGF-B和抑制血管生长的ADAMTS-1的相互调节作用可能促进了成熟的新生小动脉的形成.     

成年大鼠心肌缺血预处理的心肌保护作用及其对脂联素表达的影响

目的 通过建立大鼠心肌缺血预处理(IPC)模型及心肌梗死模型,探讨IPC对心肌的保护作用及其对脂联素表达的影响.方法 成年大鼠(4月龄)建立IPC模型及IPC后心肌梗死模型,随机分为空白对照组(0、6、12和24 h亚组)、IPC组(0、6、12和24 h亚组)、单纯心肌梗死(MI)组及IPC+MI组.采用Masson三色染色法测量心肌梗死面积(乳头肌平面梗死心肌与左心室心肌面积的比值,%),免疫组织化学法和实时荧光定量PCR法检测脂联素在心肌组织中的蛋白和mRNA表达水平,利用大鼠血浆标本做酶联免疫吸附实验,观察循环中脂联素含量的变化.结果 IPC+MI组大鼠心肌梗死面积明显小于MI组[(20±2)%比(31±3)%,P＜0.05＝.IPC组6和12 h亚组大鼠心肌组织中脂联素mRNA的表达分别是空白对照组相应时间点亚组的2.2倍和2.1倍(P均＜0.05＝.免疫组织化学结果 可见空白对照组及IPC组非缺血区心肌组织中脂联素未染色,而缺血的心肌组织局部脂联素染色加深,即脂联素在缺血区的表达明显高于非缺血区(P＜0.05＝.IPC组0、6和12 h亚组大鼠血浆中脂联素水平均显著高于空白对照组各相应时间点亚组(0 h:10.90±1.74比7.40±0.47;6 h:10.98±1.74比8.18±1.41;12 h:9.31±0.96比6.97±1.02,P均＜0.05＝.结论 IPC可减少心肌梗死的面积.IPC后心肌组织和血浆中脂联素表达水平均升高,提示脂联素参与了IPC的心肌保护作用.     

缺血预处理对糖尿病在体大鼠心肌环磷酸腺苷及环磷酸腺苷依赖蛋白激酶表达的影响

目的 探讨糖尿病大鼠心肌缺血预处理（IPC）后环磷酸腺苷（cAMP）及环磷酸腺苷依赖蛋白激酶（PKA）表达的变化.方法 选取糖尿病与非糖尿病SD大鼠各30只,分为3组（n=10）：假手术（Sham）组,缺血再灌注（I/R）组及IPC组.比较各组血清肌酸激酶（CK）、肌酸激酶同工酶（CK MB）、乳酸脱氢酶（LDH）、心肌梗死面积（MI）及心肌cAMP、PKA含量的变化.电镜标本观察心肌线粒体.结果 非糖尿病大鼠中,IPC组与I/R组比较,CK减少[（2428.32±170.19）vs（6324.06±356.26） U/L,P＜0.05],LDH减少[（1698.98±129.65）vs（4660.15±115.84） U/L,P＜0.05],CK-MB减少[（1450.43±23.56）vs（3280.90±71.33）U/L,P＜0.05],MI减少[（5.63±9.32）％vs（17.75±7.36）％,P＜0.05].糖尿病大鼠中,IPC组与I/R组比较,CK、LDH、CK-MB、MI未见明显缩小[（5962.63±145.22）vs（6012.13±124.08） U/L,（5998.44±123.40）vs（6023.54±89.01）U/L,（4011.13±81.09）vs（4380.71±76.21）U/L,（18.54±2.39）％vs（15.25±4.33）％,P＞0.05].非糖尿病大鼠中,IPC组与I/R组比较,cAMP增加[（0.61±0.07）vs（0.32±0.06） pmol/g,P＜0.05],PKA含量增加[（17.05±1.75）vs（12.68±1.13） pmol/（mg·min）,P＜0.05],糖尿病大鼠IPC组cAMP、PKA含量无明显增加[（0.35±0.04）vs （0.37±0.08） pmol/g,（12.14±2.15）vs（11.79±1.16） pmol/（mg·min）,P＞0.05].非糖尿病大鼠IPC组线粒体的损伤减轻,而糖尿病大鼠IPC组线粒体损伤未见减轻.结论 非糖尿病大鼠IPC可保护心肌.糖尿病抑制IPC的心肌保护作用,其机制可能与糖尿病大鼠心肌cAMP信号系统表达受抑制有关.     

大鼠脑缺血后海马CA1区脑红蛋白表达的变化及肢体缺血预处理对其影响

目的 观察青年和老年大鼠脑缺血后海马CA1区脑红蛋白(Ngb)表达的变化及肢体缺血预处理(LIP)对其影响. 方法 将凝闭双侧椎动脉的青年和老年大鼠均随机分为脑缺血组和脑缺血+LIP组.采用反转录聚合酶链反应(RT-PCR)和Western blot法检测海马CA1区NgbmRNA和蛋白表达,硫堇染色观察海马CA1区锥体神经元迟发性死亡(DND)情况. 结果 青年脑缺血组、青年脑缺血+LIP组、老年脑缺血组、老年脑缺血+LIP组的Ngb mRNA和蛋白表达分别为0.16±0.02和0.32±0.07、0.52±0.04和0.91±0.06、0.09±0.01和0.22±0.08、0.21±0.01和0.66±0.06.表明老年大鼠脑缺血后海马CA1区Ngb mRNA和蛋白表达较青年脑缺血大鼠降低(P<0.05),LIP可上调青年和老年大鼠脑缺血后海马CA1区Ngb mRNA和蛋白表达(P<0.05),但对老年大鼠的上调作用低于青年大鼠(P<0.05).硫堇染色显示,海马CA1区神经元密度青年脑缺血组,青年脑缺血+LIP组、老年脑缺血组和老年脑缺血+LIP组分别为(38.8±10.9)、(171.5±16.9)、(21.2±12.2)个/mm和(102.7±15.4)个/mm.表明老年大鼠LIP预防脑缺血引起的海马CA1区锥体神经元DND的作用小于青年大鼠. 结论 老年大鼠脑缺血后Ngb的表达及LIP对其上调作用较青年大鼠明显减弱,这可能是老年大鼠脑缺血后损伤较重和LIP对老年大鼠脑缺血保护作用较弱的原因之一.     

神经调节蛋白-1干预对大鼠心肌梗死后低电压区起搏阈值的影响

目的：探讨神经调节蛋白一1（NRG-1）干预对大鼠心肌梗死后低电压区起搏阈值的影响。方法：采用冠状动脉前降支结扎法建立心肌梗死大鼠模型,34只心肌梗死大鼠被随机均分为两组：NRG-1干预组（接受NRG-1腹腔注射）和对照组（接受同体积生理盐水腹腔注射）。2周后测试大鼠心肌梗死后梗死相关的低电压区的起搏阈值,并检测低电压区Cx43（连接蛋白家族的一种蛋白质）的表达。结果：药物干预2周时,NRG-1组起搏阈值明显低于对照组起搏阈值[（O．7167±0．194）V比（1．466±0．503）V,P=0．002];心肌梗死后低电压区NRG-1组Cx43表达较对照组明显增多[（O．95±0．20）比（0．30±0．15）,P〈0．001]。结论：NRG-1明显降低大鼠心肌梗死后低电压区起搏阈值,其机制可能与增加Cx43表达,改善心肌细胞间电传导有关。     

大鼠缺血预处理对心肌保护作用及脂联素表达的影响

目的探讨心肌缺血预处理(IPC)对成年和老年大鼠的心功能及心肌组织和血浆中脂联素表达的影响。方法取成年和老年大鼠各85只,将IPC成功的成年和老年大鼠各50只中,随机各取40只为IPC组,另10只再建心肌梗死(M1)模型为IPC-M1组;只穿线不阻断血流的成年和老年大鼠各30只中,随机各取20只作为假手术组,另10只建MI模型为单纯MI组。假手术组及IPC组又分别于IPC后0、6、12和24h 4个时间点观察。将未结扎冠状动脉的成年和老年大鼠各5只作为对照组。用M型超声检测心功能,Masson's Trichrome染色,测量MI面积,免疫组织化学法和RT-PCR法测心肌组织脂联素蛋白和mRNA的表达,用ELISA法检测血浆脂联素含量。结果老年大鼠IPC-MI组存活率显著低于单纯MI组和对照组(P<0.05),而成年大鼠3组生存率无变化(P>0.05)。成年大鼠IPC-MI组短轴缩短率较单纯MI组明显升高,MI面积显著减小(P<0.05);与假手术组比较,IPC组6和12h心肌组织脂联素mRNA表达明显升高(P<0.05),血浆脂联素在0、6和12h显著升高(P<0.05)。老年大鼠IPC组各时间点心肌组织脂联素mRNA表达与假手术组无显著差异,血浆脂联素24 h明显升高(P<0.05)。结论成年大鼠IPC后心肌组织和血采脂联素表达均升高,心功能改善,老年大鼠脂联素变化不明显,提示脂联素参与成年大鼠IPC发挥的心肌保护作用。     

血管性血友病因子和ADAMTS-13水平与急诊冠状动脉支架置入术后冠状动脉血流的关系

目的 探讨急性ST段抬高型心肌梗死(STEMI)患者血浆血管性血友病因子(vWF)和其裂解酶ADAMTS-13水平与急诊冠状动脉支架置入术后冠状动脉心肌梗死溶栓试验(TIMI)血流的关系.方法 根据支架释放后即刻造影显示的TIMI血流情况,将2007年9月至2009年12月期间在我院行急诊冠状动脉支架置入术的STEMI患者分为TIMI≤2级组(最终入选43例)和TIMI 3级组(最终入选43例),并选择同期冠状动脉造影正常的胸闷、胸痛患者作为阴性对照组(43例).采用双抗体夹心酶联免疫吸附法(ELISA)分别在入院即刻、冠状动脉介入术开始即刻以及介入术后1周检测患者外周血vWF和ADAMTS-13水平.结果 在不同时间TIMI≤2级组和TIMI 3级组血浆vWF水平均显著高于阴性对照组(均P＜0.05).TIMI≤2级组血浆vWF水平在不同时间均显著高于T1MI 3级组[分别为入院即刻(6721.83±1380.58)U/L比(4786.12±2362.01)U/L,P＜0.05;介入术开始即刻(5744.65±1240.71)U/L比(3011.33±2270.40)U/L,P＜0.05;介入术后1周(2001.48±931.70)U/L比(1365.17±724.12)U/L,P＜0.05].3组患者入院即刻和介入术开始即刻血浆ADAMTS-13水平差异无统计学意义.术后1周TIMI ≤2级组ADAMTS-13水平明显高于TIMI 3级组[(406.93±101.44)mg/L比(270.34±115.12)mg/L,P＜0.05].logistic回归分析表明,入院即刻vWF水平(OR:1.917,P＜0.01)和介入术开始即刻vWF水平(OR:2.016,P＜0.01)均是影响支架术后冠状动脉TIMI血流的危险因素.结论 STEMI患者急诊支架术后冠状动脉TIMI血流状况与患者术前血浆vWF水平有关,vWF与ADAMTS-13的失衡可能是急诊支架置入术后冠状动脉血流缓慢的原因之一.

Abstract：

Objective To investigate the relationship between post-stenting coronary thrombolysis in myocardial infarction (TIMI) flow and plasma von Willebrand factor (vWF) and its cleaving protease(ADAMTS-13) levels in patients with ST segment elevation myocardial infarction (STEMI). Methods STEMI patients who underwent primary percutaneous coronary intervention ( PCI ) and stenting between September, 2007 and December, 2009 were enrolled. According to the post-stenting TIMI flow, patients were divided to TIMI≤2 group (n =43) and TIMI 3 group (n =43). Patients with chest pain or dyspnea and normal coronary angiographic results served as control group ( n = 43 ). The levels of vWF and ADAMTS-13 were measured by ELISA at three time points: immediatly after admission, beginning of PCI and 1 week after PCI. Results Levels of vWF in STEMI patients at all 3 time points were significantly higher than in control patients, and the level of vWF was significantly higher in TIMI ≤2 group than in TIMI 3 group [at admission: (6721.83 ± 1380.58) U/L vs. (4786. 12 ±2362.01) U/L, P ＜0.05; at the beginning of PCI: (5744.65 ±1240. 71) U/L vs. (3011.33 ±2270.40) U/L, P＜0. 05 and at 1 week after PCI: (2001.48 ± 931.70) U/L vs. ( 1365. 17 ± 724. 12 ) U/L, P ＜ 0. 05]. ADAMTS-13 levels were similar among groups at admission and at beginning of PCI, however, the level of ADAMTS-13 at 1 week after PCI was significantly higher in TIMI≤2 group than that in TIMI 3 group [(406. 93 ± 101.44 )mg/L vs. ( 270. 34 ± 115.12) mg/L, P ＜0. 001]. Logistic regression analysis showed that both vWF at admission(OR=1.917, P＜0.01) and vWF at the beginning of PCI (OR=2.016, P＜0. 01) were risk factors of TIMI≤2. Conclusion Increased vWF during peri-PCI periods was associated with post-stenting coronary TIMI ≤2 after primary PCI in STEMI patients, and the imbalance between vWF and ADAMTS-13 may thus play an important role in the development of slow flow post PCL     

鼠龄对急性心肌梗死大鼠Bcl-2和Bax表达的影响

目的 建立成年和老年Wistar大鼠急性心肌梗死模型,比较鼠龄对大鼠冠状动脉(冠脉)结扎后不同时间点的凋亡指数及凋亡相关蛋白Bcl-2和Bax表达的影响.方法 115只6～24月龄大鼠中,95只结扎冠脉左前降支,80只(成年、老年大鼠各40只)术后存活,根据鼠龄分为老年心肌梗死组(40只)和成年心肌梗死组(40只),按结扎前降支后的1 h、3 h、5 h、1 d和7 d各分为5组(每组8只).假手术老年组和假手术成年组各10只.心肌梗死组分别于冠脉结扎后1、3、5 h和1、7d时记录血流动力学参数,包括心率、左室收缩压(LVSP)、左室终末舒张压(LVEDP)和左室内压最大收缩和舒张速率(±dp/dtmax).采用伊文蓝-红四氮唑(TTC)染色和原位末端标记(TUNEL)法检测心肌坏死和凋亡程度.免疫组化染色检测心肌内Bcl-2和Bax的形成.结果 大鼠心肌在冠脉结扎后的1 h内即有凋亡出现,并且凋亡达高峰的时间老年心肌梗死组较成年心肌梗死组早.在冠脉结扎3 h,老年心肌梗死组与成年心肌梗死组的凋亡指数分别为(51.90±23.15)%与(18.67±17.15)%,差异有统计学意义(P<0.01).Bcl-2蛋白的表达值老年假手术组和成年假手术组分别为(2.7±0.9)分和(1.8±0.8)分,差异有统计学意义(P<0.05).Bax蛋白的表达两组分别为(6.2±2.9)分和(4.2±1.5)分,差异有统计学意义(P<0.05).结论 老年大鼠抵抗心肌缺血的能力差,鼠龄可能会改变Bcl-2和Bax蛋白的表达而增加心肌细胞凋亡.     

心肌脂联素信号通路增强可能是心肌缺血预处理保护心肌的部分新机制

目的 探讨脂联素(APN)信号通路在心肌缺血预处理中的作用及机制。方法 建立对照组,心肌缺血预处理(ischemic preconditioning,IPC)和缺血/再灌注(myocardial ischemia/reperfusion,MI/R)损伤小鼠模型,每组8只C57BL/6J小鼠。ELISA法检测血浆APN水平,超声检测心功能,TTC法观察心肌梗死面积,TUNEL染色检测心肌细胞凋亡,Western blot检测APN受体（adiponectin receptor,AdipoR）, 腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK)分子的表达。结果 与对照组血浆APN〔(19.08±2.15)μg/ml〕相比,IPC组和MI/R组缺血30 min后血浆APN水平降低（P<0.01）;与IPC组血浆APN〔(15.4±2.09)μg/ml〕相比,MI/R组血浆APN水平降至更低〔(13.95±1.75)μg/ml〕（P<0.05）;与对照组左室射血分数(76.37±7.24)相比,MI/R组和IPC组左室射血分数（57.15±7.32和66.37±6.09）均降低（P<0.05）;与MI/R组左室射血分数相比,IPC组左室射血分数升高（P<0.01）;与对照组左室短轴缩短率(52.13±4.80)相比,MI/R组和IPC组左室短轴缩短率（37±8.14和44.9±6.52）降低（P<0.01）;与MI/R组左室短轴缩短率相比,IPC组左室短轴缩短率升高（P<0.01）;与对照组左室舒张末内径〔(3.13±0.59)mm〕相比,MI/R组和IPC组左室舒张末内径增加〔(3.50±0.48)mm和(3.23±0.50)mm〕（P<0.05）;与MI/R组左室左室舒张末内径相比,IPC组左室舒张末内径减少（P<0.01）;与对照组左室收缩末内径（1.95±0.59）mm相比,MI/R组和IPC组左室左室收缩末内径增加分别为〔(2.26±0.48)mm和(2.15±0.21)mm〕（P<0.05）;与MI/R组左室左室收缩末内径相比,IPC组左室收缩末内径减少（P<0.01）;与对照组心肌梗死面积相比,MI/R组和IPC组心肌梗死面积增加（45.7±3.92,40.9±4.1）（P<0.01）;与MI/R组心肌梗死面积相比,IPC组心肌梗死面积增加减少（P<0.05）;与对照组TUNEL阳性细胞相比,MI/R组和IPC组TUNEL阳性细胞增加（12.16±1.93和8.96±1.49）（P<0.01）;与MI/R组TUNEL阳性细胞相比,IPC组TUNEL阳性细胞减少（P<0.05）;与对照组Caspase-3活力〔(1.93±1.82)nmol/(h·mg)〕相比,MI/R组和IPC组Caspase-3活力增加〔(5.82±2.72和4.68±2.31）nmol/（h·mg）〕（P<0.01）;与MI/R组Caspase-3活力相比,IPC组Caspase-3活力减少（P<0.05）;与对照组心肌AdipoR1的表达(0.86±0.26)相比,MI/R组和IPC组心肌AdipoR1表达减少（0.57±0.15和0.72±0.22）（P<0.05）;与MI/R组心肌AdipoR1的表达相比,IPC组心肌AdipoR1的表达增加（P<0.05）;而AdipoR2的表达没有变化;与对照组心肌pAMPK/AMPK的表达(1.6±0.24)相比,MI/R组和IPC组心肌pAMPK/AMPK的表达减少（1.04±0.13和1.28±0.13）（P<0.05）;与MI/R组心肌pAMPK/AMPK的表达相比,IPC组心肌pAMPK/AMPK的表达增加（P<0.01）。结论 缺血预处理减轻心肌再灌注损伤机制部分可能在于心肌APN/AdipoR/AMPK信号通路增强。     

过氧化物酶增殖物激活受体γ在不同月龄大鼠肾脏中的表达

目的 观察过氧化物酶增殖物激活受体γ(PPARγ)在大鼠肾脏衰老过程中的表达分布,探讨其可能作用机制.方法 分别以3月龄、12月龄和24月龄SD大鼠为模型,采用Western印迹、免疫组化、原位杂交的方法检测PPARγ蛋白、核酸在不同年龄大鼠肾组织中的表达.结果 PPARγ蛋白在肾组织表达,3月龄大鼠为0.94±0.05,明显高于24月龄大鼠0.78±0.02(t=7.08,P＜0.01),亦高于12月龄大鼠0.87±0.04,但差异无统计学意义(t=2.49,P＞0.05).免疫组化结果显示,PPARγ蛋白在各年龄组大鼠肾小管、集合管上皮细胞中均有分布,主要分布于细胞核内,在老年大鼠肾小球系膜细胞及壁层上皮细胞内也有阳性染色.原位杂交结果显示,PPARγ mRNA的表达分布与免疫组化结果一致.半定量分析显示,在大鼠肾组织的衰老过程中,PPARγ基因表达呈下降趋势.结论 PPARγ作为核转录因子参与了大鼠肾脏衰老过程调控.