Improved rat model for cerebral vasospasm studies

Abstract

While the rat has been used extensively in subarachnoid hemorrhage (SAH)-cerebral vasospasm studies, concerns exist whether this animal represents a usable model because its time course and pattern of cerebral vasospasm following SAH is not comparable to that observed in man. At present, our knowledge of the rat model is based almost exclusively on studies using a 'single hemorrhage' method. Since there is a positive correlation between severity of cerebral vasospasm, and volume of subarachnoid blood, an obvious question is whether the rat will show modifications in vascular responses when insulted by a second SAH. Here, an SAH was produced in rats using a 'double hemorrhage' method. Following SAH, cerebral arteries showed pathological alterations, significant decreases in luminal perimeter, and increases in arterial wall thickness, over a 7-day post-SAH period. The above vascular features are considered to be indicative of cerebral vasospasm and their presence over a 7-day post-SAH period represents a significant time extension when compared to a single hemorrhage. These modified vascular responses made the double hemorrhaged rat a much-improved animal model. [Neurol Res 2001; 23: 761-766]     

Physiological levels of β-amyloid induce cerebral vessel dysfunction and reduce endothelial nitric oxide production

Abstract

β-amyloid (Aβ), the major component of senile plaques in Alzheimer's disease (AD), normally circulates in the blood at nanomolar levels but is elevated in AD. Previous studies have found that high concentrations (10^-5 -10^-4 M) of Aβ result in neuronal cell death. Here we show that physiological levels of soluble Aβ can induce dysfunction in perfused rat cerebral vessels and in cultured endothelial cells. At concentrations of 10^-9 -10^-6 M, Aβ induced a significant concentration-dependent reduction of NO production in endothelial cells. At 10^-8 M, Aβ significantly decreased the sensitivity of cerebral vessels to acetylcholine (ACh), an endothelium dependent vasodilator. At 10^-7 M and higher concentrations, Aβ significantly reduced the maximum response of vessels to ACh, and induced significant endothelial cell death. Aβ (10^-9 -10^-5 M) did not cause any detectable change in nitric oxide synthase levels. The results suggest that a modest increase in the concentration of Aβ above its normal physiological level in the circulation, as found in the early stages of AD, results in decreased NO production and vessel sensitivity to endothelium-dependent vasodilation that could lead to constricted blood vessels and ischemia in the surrounding tissue. Further increases in Aβ concentration, which may occur in the later stages of AD, result in cell death and decreased maximum vasodilator response of cerebral vessels. [Neurol Res 2001; 23: 506-512]     

Expression of Adhesion Molecules and Leukocyte Recruitment into Gastric Mucosa Following Ischemia-Reperfusion

Leukocyte infiltration is an important step inpostischemic tissue damage. This study aimed todetermine the expression of adhesion molecules and theirrelationship with leukocyte infiltration in thepostischemic gastric mucosa. Gastric tissue was obtainedfrom rats subjected to 30 min gastric ischemia followedby reperfusion. Sections were stained with specificantibodies against (1) L-selectin and (2) LFA-1 on leukocytes, (3) ICAM-1 on endothelial cells,(4) PMNs, and (5) monocytes. Stained cells or bloodvessels in mucosal tissue were counted using imageanalysis. Results showed that from 5 min of reperfusion, numbers of L-selectin-positive cells decreased,whereas LFA-1-positive cells and PMNs increased comparedwith controls. ICAM-1 expression did not increase until60 min of reperfusion. Monocyte numbers were unaffected by reperfusion. We conclude thatgastric ischemiareperfusion results in a rapid influx ofLFA-1-positive cells, the majority of which are PMN.L-Selectin is shed from these cells allowing them to adhere to the microvasculature viaconstitutively expressed ICAM-1.     

血瘀证兔血清对培养的血管内皮细胞活性因子基因表达的影响

【目的】探索血瘀证形成和发展过程中血管内皮细胞活性因子内皮素和一氧化氮 (NO)改变的分子机理。【方法】用半定量RT -PCR方法 ,观察血瘀证兔模型血清对体外培养的血管内皮细胞内皮素 (ET)和组成型NO合成酶 (constitutivenitricoxidesynthase ,cNOS)基因表达的影响。【结果】血瘀证动物模型血清导致体外培养的内皮细胞中ET - 1mRNA表达升高 (P <0 .0 1) ,cNOSmRNA表达下降 (P <0 .0 1) ,两者呈显著负相关 (r=- 0 .857,P <0 .0 1)。【结论】血管内皮细胞中ET基因高表达及cNOS基因低表达导致的二者平衡失调在血瘀证形成和发展过程中起着重要作用。     

Soluble adhesion molecule profile in normal pregnancy and pre-eclampsia

Objective: An exaggerated inflammatory response has been implicated as the cause of endothelial cell dysfunction and the maternal syndrome of pre-eclampsia. Adhesion molecules play a central role in the adherence of leukocytes to endothelial cells and the subsequent migration of white blood cells into perivascular tissue. Cellular forms of adhesion molecules mediate specific steps of leukocyte-endothelial cell interaction, and have been implicated in the pathophysiology of pre-eclampsia. Soluble forms of these molecules can be detected in plasma, and their concentrations are thought to reflect the degree of activation of a particular cell type. Elevations in soluble P-selectin (sP-selectin) reflect platelet activation; changes in soluble L-selectin (sL-selectin) suggest leukocyte activation; and an increase in soluble forms of E-selectin (sE-selectin), vascular cell adhesion molecule 1 (sVCAM-1), intercellular adhesion molecule 1 (sICAM-1) and platelet endothelial cell adhesion molecule (sPECAM-1) indicate endothelial cell activation/dysfunction. The objective of this study was to determine whether normal pregnancy and pre-eclampsia were associated with changes in the concentrations of soluble selectins and members of the immunoglobulin superfamily of adhesion molecules. Study design: A cross-sectional study was conducted to determine the plasma concentrations of sL-selectin, sE-selectin, sP-selectin, sVCAM-1, sICAM-1 and sPECAM-1 in peripheral blood obtained from non-pregnant women (n = 20), normal pregnant women (n = 100) and patients with pre-eclampsia (n = 55). Concentrations of soluble adhesion molecules were determined with enzyme-linked immunoassays. Parametric statistics were used for data analysis. Results: Normal pregnancy was associated with a significant increase in the maternal plasma concentration of sP-selectin, a decrease in sL-selectin, and no change in sE-selectin, sVCAM-1, sICAM-1 and sPECAM-1. In contrast, pre-eclampsia was associated with a significant increase in sP-selectin, sE-selectin and sVCAM-1, a decrease in sL-selectin, but no change in sICAM-1 and sPECAM-1 concentrations. Conclusions: The increased concentration of sP-selectin and decreased sL-selectin, as well as the lack of change in endothelial cell-associated soluble adhesion molecules suggest that pregnancy is associated with platelet and leukocyte activation, but not endothelial cell activation. In contrast, pre-eclampsia appears to be characterized by activation of platelets, leukocytes and endothelial cells.     

血瘀证兔模型血管内皮细胞中一氧化氮合酶 的基因表达及其分泌一氧化氮的变化

【目的】了解实验性血瘀证动物模型血管内皮细胞中一氧化氮合酶(NOS)的基因表达及其分泌NO的变化。【方法】用半定量RT-PCR方法检测模型组体内血管内皮细胞及体外培养的细胞中组成型一氧化氮合酶mRNA的表达,并相应测定分泌的NO水平。【结果】与对照组比较,模型组兔体内血管内皮细胞中组成型NOS(cNOS)基因表达以及血浆和原代培养液中NO水平皆明显下降(P＜0.01),同期血浆中NO含量与内皮细胞中cNOSmRNA的表达水平呈正相关(r=0.739,P＜0.01)。两组间体外培养的传代细胞中cNOS基因表达及培养液上清中NO含量无明显差异(P＞0.05),但NO水平都比各自原代培养液中的明显升高(P＜0.01,P＜0.05)。【结论】短期内血瘀证兔模型体内内源性NO水平降低主要是cNOS基因表达下降导致的,随时间的延长,不排除诱导型NOS(iNOS)及体内其他因素对分泌NO的综合影响。     

川芎嗪对家兔血管内皮细胞修复的影响

【目的】观察川芎嗪对血管损伤后内皮细胞修复的作用 ,探讨其作用机理与环节 ,为显微血管外科提供新的用药依据。【方法】新西兰大耳白兔 2 4只 ,行右侧股动脉切断后即刻端端吻合造模 ,术后随机分成川芎嗪治疗组、肝素治疗组及空白对照组予处理 ,术后 1、 3、 7、 14d分别切取大白兔吻合段动脉 ,作电镜扫描检测 ,观察内皮细胞的生长情况并作组间比较。【结果】在促进血管吻合术后血管内皮细胞的修复 ,促进血流通畅方面川芎嗪组与肝素组相当 (P >0 .0 5) ,两者均优于空白组 (P <0 .0 5)。【结论】川芎嗪能促进血管损伤后内皮细胞的修复 ,在显微血管外科具有肯定的使用价值。     

应用钛环钉行人工血管旁路术的实验研究

目的　探讨应用钛环钉行人工血管旁路术后人工血管及髂动脉腔表面内皮细胞形态学变化。方法　选用14 只健康雄性恒河猴,用3 mm 直径的ePTFE 人工血管置换左髂总动脉,近端用60 无创缝线吻合,远端用73Ⅱ型血管吻合器吻合。术后4 周,取出吻合口行光镜及电镜检查。结果　钛环钉组血管损伤反应轻,吻合口有完整内膜覆盖;而缝线组损伤反应重,吻合口内膜覆盖不完整,有血栓样组织沉积。结论　钛环钉组吻合口在术后4 周均形成完整的内膜,对预防吻合口早期血栓形成及晚期内膜增生有重要意义     

调平康片联合开搏通治疗原发性高血压临床研究

为评价中药复方调平康片联合小剂量开搏通治疗原发性高血压的综合疗效。采用随机，双盲、对照方案将６１例合格高血压（ＥＨ）患者随机分为两组，分别予以调平康片加开搏通（中西药组），安慰剂加开搏通（西药组）治疗。     

血瘀证动物细胞损伤模型的研制

[目的]探索建立血瘀证细胞损伤模型的方法。[方法]用两种方法,即用血瘀证兔模型血管内皮细胞直接培养的方法和用血瘀证兔模型血清损伤培养的血管内皮细胞方法,研制血瘀证细胞损伤模型。[结果]第一种方法原代培养物血管内皮细胞出现了病理性损伤及内分泌功能的改变,初步表明能直接反映体内的病理状态,但其病理特征并未随细胞传代得以保留;第二种方法培养的细胞同样体现了类似前者的病理状态,且更易于复制。[结论]初步表明所建立的细胞损伤模型从功能和结构上都反映了务大辩论辛整体动物模型及部分临床病人的病理特征,可应用于探讨血瘀证实质和活血化瘀作用机理的研究。