Real-time myocardial contrast echocardiography for assessing perfusion and function in healthy and infarcted wistar rats

Real-time myocardial contrast echocardiography (MCE) is a noninvasive perfusion imaging method, whereas technical and resolution problems impair its application in small animals. Hence, we investigated the feasibility of MCE in experimental cardiovascular set-ups involving healthy and infarcted myocardium in rats. Twenty-five male Wistar rats were examined under volatile anesthesia (2.5% isoflurane) with high-resolution conventional 2-D echocardiography (2DE) and real-time MCE (Sonos 7,500 with 15MHz-transducer, Philips Medical Systems, Andover, MA, USA) in short-axis view. Contrast agent (SonoVue, Bracco, Milan, Italy) was infused as a bolus into a sublingual vein. Background-subtracted contrast signal intensity (SI) was measured off-line in six end-systolic segments and fitted to an exponential curve (gamma variate). Derived peak SI was subsequently calculated and compared with wall motion and common functional measured quantities (left ventricular end-diastolic diameter [LVEDD], area shortening [AS]). Recordings were performed before and 14 days after left anterior descending (LAD) ligature. Infarction induced anterior wall motion abnormalities (WMA) in all animals (16 akinetic, 9 hypokinetic), increased LVEDD (9.1 +/- 0.6 vs. 7.9 +/- 0.6 mm, p < 0.001), reduced AS (36.1 +/- 10.0 vs. 59.5 +/- 4.1%, p < 0.001) and reduced anterior segmental SI (0.4 +/- 0.4 dB akinetic / 1.7 +/- 1.7 dB hypokinetic vs. 15.8 +/- 10.9 dB preinfarct, p < 0.001 / p < 0.001). Segmental SI in normokinetic segments remained unchanged. Area at risk (perfusion defect) correlated well with WMA (r = 0.838). These data confirmed high-resolution real-time MCE as a rational tool for assessing myocardial perfusion of Wistar rats. It may therefore be a useful diagnostic tool for in-vivo cardiovascular research in small animals.     

促红细胞生成素对大鼠心肌缺血-再灌注心律失常的影响

目的:观察促红细胞生成素(erythropoietin,EPO)对大鼠心肌缺血-再灌注心律失常的影响并探讨其作用机制。方法:采用结扎左冠状动脉前降支30min再灌注120min的方法建立大鼠心肌缺血-再灌注损伤模型。将60只SD大鼠随机分为3组(假手术组、缺血-再灌注组、EPO治疗组)。连续监测肢体Ⅱ导联心电图记录再灌注心律失常情况;测定再灌注末心肌组织丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)、Na+-K+-ATP酶和Ca2+-ATP酶的变化。结果:EPO降低再灌注室性心律失常的发生率与持续时间,使心律失常评分显著降低;EPO减少再灌注末心肌MDA含量,提高心肌GSH-Px、CAT、Na+-K+-ATP酶和Ca2+-ATP酶的活性,对心肌SOD活性无影响。结论:EPO具有抗心肌缺血-再灌注室性心律失常的作用,其机制可能与减轻氧自由基及钙超载的损害有关。     

Protective Effects of Estradiol on Myocardial Contractile Function Following Hemorrhagic Shock and Resuscitation in Rats

Background:

Hemorrhagic shock (HS) results in myocardial contractile dysfunction. Studies showed that 17β-estradiol protects the myocardium against contractile dysfunction. The study investigated the cardioprotective effects of treatment with 17β-estradiol before resuscitation following 1 h of HS and resuscitation.

Methods:

Male Sprague-Dawley rats were assigned to 2 sets of experimental protocols: Ex vivo and in vivo treatment and resuscitation. Each set had three experimental groups (n = 6 per group): Normotensive (N), HS and resuscitation (HS-R) and HS rats treated with 17β-estradiol (E) and resuscitated (HS-E-R). Rats were hemorrhaged over 60-min to reach a mean arterial blood pressure of 40 mmHg. In the ex vivo group, hearts were resuscitated by perfusion in the Langendorff system. In the 17β-estradiol treated group, 17β-estradiol 280 µg/kg was added for the first 5 min. Cardiac function was measured. Left ventricular generated pressure (LVGP) and +dP/dt were calculated. In the in vivo group, rats were treated with 17β-estradiol 280 µg/kg s.c. after 60-min HS. Resuscitation was performed in vivo by the reinfusion of the shed blood for 30-min to restore normotension.

Results:

Treatment with 17β-estradiol before resuscitation in ex vivo treated and resuscitated isolated hearts and in the in vivo treated and resuscitated rats following HS improved myocardial contractile function. In the in vivo treated group, LVGP and +dP/dt max were significantly higher in 17β-estradiol treated rats compared to the untreated group (LVGP 136.40 ± 6.61 compared to 47.58 ± 17.55, and +dP/dt 661.85 ± 49.88 compared to 88.18 ± 0.85). Treatment with 17β-estradiol improved LVGP following HS.

Conclusions:

The results indicate that treatment with 17β-estradiol before resuscitation following HS protects the myocardium against dysfunction.     

脑源性神经营养因子缓释微球对周围神经损伤大鼠的神经保护作用

目的 观察脑源性营养因子缓释微球(BDNF-PLGA缓释微球)对大鼠周围神经损伤的保护作用。方法 采用复乳化溶剂挥发法制备BDNF-PLGA缓释微球。40只SD大鼠随机分为假手术组、模型组、BDNF组和BDNF-PLGA缓释微球组;除假手术外,其它30只SD大鼠,制备坐骨神经钳夹损伤模型。术后神经损伤局部注射BDNF-PLGA缓释微球,观察大鼠的大体形态、步态、关节活动等情况;术后4周进行神经行为学评分,检查神经传导速度(NCV)、波幅、潜伏期和复合肌肉动作电位(CMAP)的幅度,以及组织病理学观察。结果 BDNF-PLGA缓释微球组明显改善坐骨神经损伤大鼠的步态、关节活动等一般状况。BDNF-PLGA缓释微球可有效地改善大鼠损伤神经功能,到第4周时已基本恢复正常,对神经功能恢复明显快于BDNF组。与模型组比较,BDNF-PLGA缓释微球组显著提高大鼠NCV,增大电位波幅,缩短潜伏期(P<0.01)。术后4周,BDNF-PLGA缓释微球组的大鼠坐骨神经NCV、波幅和潜伏期,CMAP波幅及恢复率均显著优于BDNF组。BDNF-PLGA缓释微球明显改善坐骨神经髓鞘和轴突结构破坏,髓神经纤维的髓鞘肿胀、碎裂,神经纤维中的空泡及空泡变性等组织病理学改变。结论 BDNF-PLGA缓释微球对周围神经损伤具有显著的保护作用。     

阿司匹林对局灶性脑缺血-再灌注大鼠神经调节蛋白1和存活素表达的影响

目的观察大鼠局灶性脑缺血-再灌注后(CI/RP)神经调节蛋白1(NRG-1)和存活素(Survivin)的表达规律及阿司匹林对其表达的影响。方法取健康雄性SD大鼠60只,将其随机分为阿司匹林组和对照组,每组30只。每组按再灌注时间分为6、24h及3、5、7d亚组,每个亚组6只大鼠。采用线栓法制作大脑中动脉阻塞(2h)模型。阿司匹林组于再灌注后即刻及每日清晨腹腔注射阿司匹林(80mg/kg,溶解于1.5ml的10%L-赖氨酸等渗盐水溶液中)1次。对照组在相同时间点注射10%L-赖氨酸1.5ml。观察再灌注后不同时间大鼠神经功能缺损评分及NRG-1、存活素的表达。结果①再灌注后24h,3、5、7d神经功能缺损评分,阿司匹林组分别为1.47±0.11、1.22±0.08、0.85±0.15、0.59±0.12,对照组为1.87±0.18、1.45±0.14、1.05±0.08、0.75±0.15,两组比较差异均有统计学意义(P<0.05)。②CI/RP后各时间点阿司匹林组和对照组大鼠梗死侧神经元的细胞核及细胞质均有NRG-1和存活素的表达。梗死中心区两种阳性细胞表达数在再灌注后6h最多,随后逐渐减少,7d最少;梗死...     

精索静脉曲张对大鼠睾丸内分泌功能的影响

目的：探讨精索静脉曲张(VC)对大鼠睾丸支持细胞分泌功能的影响。方法选择 SD 雄性大鼠40只,随机分为实验组和对照组,每组20只。实验组建立 VC 模型,对照组不缩窄精索静脉。造模后12周,检测两组睾丸组织内雄激素结合蛋白、抑制素 B 和睾酮浓度。结果两组睾丸组织雄激素结合蛋白表达情况比较差异无统计学意义(P >0.05);实验组抑制素 B 及睾酮水平均低于对照组(P <0．05)。结论 VC 可使睾丸支持细胞抑制素 B 和睾酮分泌减少,影响精子发育、成熟,导致男性不育。     

磷酸肌酸对大鼠子宫缺血再灌注损伤的影响

目的：探讨外源性磷酸肌酸预处理对大鼠子宫缺血再灌注损伤的保护作用及其机制。方法选择 SD雌性大鼠45只,随机分为假手术组、缺血再灌注组和干预组,每组15只。干预组于缺血前30 min 经腹腔注射磷酸肌酸注射液10 mg/ kg,测定子宫组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平,并观察子宫病理组织学改变。结果与假手术组比较,缺血再灌注组和干预组大鼠子宫组织 SOD 活性明显降低,MDA 含量明显增加(P <0．05);与缺血再灌注组比较,干预组 SOD 活性升高,MDA 含量降低(P <0．05)。干预组病理组织学观察炎性反应较缺血再灌注组明显减轻。结论磷酸肌酸对大鼠子宫缺血再灌注损伤有保护作用,其机制可能与其增强 SOD 活性有关。     

大鼠卵巢组织冷冻复苏及自体异位移植研究

目的：探讨直接覆盖玻璃化冷冻(direct cover vitrification, DCV)在冷冻大鼠卵巢组织中的效果,并对自体异位移植后卵巢组织存活状况及内分泌情况进行分析。方法性成熟的 Wistar 大鼠50只随机分为 A、B、C、D 组, A 和 B 组各20只,C 和 D 组各5只。 A 组为新鲜卵巢组织移植;B 组卵巢组织经 DCV 冷冻保存2周复苏后移植;C 组为去势对照;D 组为假手术对照。自体异位移植6周后检测大鼠血清中雌二醇(E2)水平,计算卵泡密度,观察移植卵巢组织形态学及增殖细胞核抗原(proliferating cell nuclear antigen, PCNA)的表达情况。结果大鼠卵巢组织移植存活的卵巢组织周围可见血管供应,移植失败的卵巢组织呈纤维化状态,与周围组织血供不明显。 B 组卵巢组织移植存活率低于 A 组(P <0．05)。 B 组卵巢组织中卵泡密度均低于 A、D 组,且 A 组低于 D 组(P <0．05)。 A、B 组血清 E2水平高于 C 组,低于 D 组(P <0．05)。 A、B 组卵巢组织 PCNA 阳性率均低于 D 组,且 B 组低于 A 组(P <0．05)。结论大鼠卵巢组织经 DCV 法冻融自体异位移植后部分卵泡能存活并可恢复内分泌功能。     

降钙素对白介素-1β诱导的大鼠软骨细胞炎性反应的作用

目的：探讨降钙素对白介素-1β(IL-1β)诱导的大鼠骨关节炎(OA)中基质金属蛋白酶-13(MMP-13)、Ⅱ型胶原、p38及P-p38表达的影响。方法分离SD大鼠关节软骨,消化、培养。采用甲苯胺蓝染色鉴定软骨细胞。将第2代软骨细胞分为空白对照组、IL-1β诱导组和IL-1β+降钙素治疗组,空白对照组和IL-1β诱导组分别给予完全培养基、含10 ng/ml IL-1β的完全培养基,IL-1β+降钙素治疗组先加入含10 ng/ml IL-1β的完全培养基15 min,再加入50 ng/ml降钙素,均培养24 h。用透射电镜观察细胞的超微结构,蛋白免疫印迹检测MMP-13、Ⅱ型胶原、p38、P-p38表达。实时荧光定量PCR检测MMP-13、Ⅱ型胶原 mRNA的表达。结果3组软骨细胞p38蛋白及mRNA表达水平比较差异无统计学意义(P>0．05)。 IL-1β诱导组和IL-1β+降钙素治疗组P-p38、MMP-13蛋白及mRNA表达水平均高于空白对照组,但IL-1β+降钙素治疗组低于IL-1β诱导组( P<0．05);IL-1β诱导组和IL-1β+降钙素治疗组Ⅱ型胶原蛋白及mRNA表达水平低于空白对照组(P<0．05),IL-1β+降钙素治疗组高于IL-1β诱导组,但差异无统计学意义(P>0．05)。结论 IL-1β可以体外诱导大鼠软骨细胞形成OA病变。降钙素对IL-1β诱导的大鼠OA模型中软骨细胞损伤具有一定的改善作用,其机制之一可能是通过抑制p38信号通路的激活降低MMP-13的表达,减少Ⅱ型胶原的降解,从而延缓OA进程。     

泽丹冲剂对盆腔炎性大鼠子宫TGF-β_1、Smad_3的影响研究

目的:研究泽丹冲剂对慢性盆腔炎大鼠子宫组织TGF-β1、Smad3表达的影响,阐明以利湿化瘀法为主的泽丹冲剂作用机制。方法:大鼠双侧宫腔内注射大肠杆菌混悬液(浓度约为6×106)0.2mL建立慢性盆腔炎大鼠模型。造模成功后,随机分成泽丹冲剂高、中(8g·kg、4g·kg)剂量组,妇乐颗粒组(2.5g·kg),模型组和正常组。灌胃给药21d后,采用Western Blot法检测大鼠子宫组织TGF-β1、Smad3表达。结果:与模型组比较,泽中、高剂量组,妇乐组子宫组织TGF-β1、Smad3表达均明显降低(P0.05),但泽中、高剂量组优于妇乐组(P0.05)。结论:泽丹冲剂通过降低TGF-β1、Smad3的异常高表达,减轻慢性盆腔炎大鼠子宫组织的纤维化及粘连,因而对慢性盆腔炎具有良好的治疗作用。