共聚焦激光扫描显微镜活体观测川芎嗪和去甲基肾上腺素对生理状态下家兔大脑皮质内微循环的影响

目的 :用共聚焦激光断层扫描显微镜活体观测川芎嗪和去甲基肾上腺素对正常家兔大脑皮质内微循环的影响。方法 :在开放颅窗的家兔动物模型上 ,荧光素标记血浆 ,罗丹明 6G标记WBC ,用共聚焦激光扫描显微镜活体观测正常状态下家兔大脑皮质内 3 0 0 μm深处微循环 ,并经图像分析系统测量数据 ,用SAS软件包进行统计学分析。结果 :川芎嗪对大脑皮质内动脉的作用与去甲基肾上腺素相似 ,认为川芎嗪既可兴奋β受体 ,也可兴奋α受体。去甲基肾上腺素和川芎嗪使平均口径为 12 1.5 6μm ,60 .0 0 μm的动脉血管运动 ,而缘流在血管运动时是保持不变的 ;在毛细血管处可引起不同程度的血管舒缩运动。结论 :在共聚焦激光扫描显微镜活体观测正常状态下家兔大脑皮质内3 0 0 μm深处微循环 ,用去甲基肾上腺素和川芎嗪使平均口径为 12 1.5 6μm ,60 .0 0 μm的动脉血管运动时 ,血液缘流是保持不变的 ;在毛细血管处可引起不同程度的血管舒缩运动     

脑血管内皮形态与血液缘流保护性屏障

用共聚焦激光扫描显微镜,在开放颅窗的大耳白家兔模型上活体观测激光断层扫描光学切片,切片厚2μm或5μm,家兔血浆用荧光素标记、图像分析系统测量分析不同口径血管的轴流、缘流的荧光辉度,并描绘出辉度曲线。结果表明:在大脑皮质内动脉的口径在50μm以上者,辉度曲线呈"平台"形,在20μm以下者,辉度曲线呈"抛物线"形,这与在研究血管内皮形态时提出的"咀液缘流保护性屏障假说"相符合,证明了"血液缘流保护性屏障"的存在,随文附有血管内皮形态学扫描电镜研究资料。     

“血液缘流保护性屏障假说”的证明

在提出“血液缘流保护性屏障假说”的基础上，采用共聚焦激光扫描显微镜（MRC6OO）详细观察了不同口径的家兔大脑皮质内血管内的血液轴流、缘流的荧光辉度，描绘出荧光辉度曲线，测量了在生理、休克状态下，去甲肾上腺素、川芎嗪作用于大脑皮质内微血管时血管口径变化、血管运动及血液缘流厚度的变化，用SAS软件包做统计学分析处理，认为“血液缘流保护性屏障”存在。并已在血管内皮凸凹不平处，缘流层厚，保护作用大，并与脑血管疾病的发牛发展可能有直接关系；血液层流状态人20um以上血管内表现明显，这种状态与血管内皮的光滑程度有关。     

共聚焦激光扫描显微镜(MRC600)活体观测川芎嗪和去甲基肾上腺素对休克状态下家兔大脑皮质内微循环的影响

目的 :共聚焦激光扫描显微镜活体观测川芎嗪和去甲基肾上腺素对休克状态下家兔大脑皮质内微循环的影响。方法 :在开放颅窗的家兔模型上 ,荧光素标记血浆 ,罗丹明 6G标记WBC ,用共聚焦激光扫描显微镜活体观测川芎嗪和去甲基肾上腺素对休克状态下家兔大脑皮质内微循环的影响 ,并经图像分析系统测量数据 ,用SAS软件包进行统计学分析。结果 :①川芎嗪抗休克效果优于去甲基肾上腺素 ;②去甲基肾上腺素在休克状态下对口径为 60 .15 μm的动脉血管处未引起明显的血管运动 ,而川芎嗪能引起血管运动 ,尤以大剂量川芎嗪引起强烈的血管运动 ;③川芎嗪和去甲基肾上腺素增加或保持血液缘流厚度不变 ,可能是两者抗休克机制发挥作用的途径之一 ;④川芎嗪和去甲基肾上腺素引起血管运动 ,尤以中小血管处明显。结论 :川芎嗪抗休克效果优于去甲基肾上腺素。川芎嗪和去甲基肾上腺素增加或保持血液缘流厚度不变 ,可能是两者抗休克机制发挥作用的途径之一     

腺苷对营养性肥胖大鼠腺系膜微循环影响的初步观察

目的探讨腺苷(CPA)对大鼠营养性肥胖小肠肠系膜微循环的影响。方法大鼠分为普通饲料喂养组(A组),高能饲料喂养肥胖模型组(B组),CPA+普通饲料喂养组(C组)、CPA+高能饲料喂养模型组(D组)。检测大鼠体质量、小肠肠系膜微循环的指标,计算Lee’s指数。结果(1)A组大鼠体质量增加了(35.4±27.9)%;B组大鼠体质量增加(84.0±33.8)%,B组大鼠体质量增长率大于A组(P<0.01);D组大鼠体质量增加(75.2±16.0)%均小于B组(P<0.01),但D组与C组大鼠体质量之间差异无明显意义(P>0.05);D组大鼠体质量增长(75.2±16.0)%明显高于A组(P<0.05)。(2)B组Lee’s指数为3.180±0.159大于A组(P<0.05),D组3.031±0.075小于B组(P<0.05);D组与C组、D组与A组Lee’s指数之间差异无显著意义(P>0.05)。(3)大鼠小肠肠系膜微循环:A组血管口径(5.18±0.56)μm;B组血管口径(8.25±0.63)μm,B组明显大于A组(P<0.05);D组血管口径(5.25±0.25)μm明显小于B组(P<0.05);A组血管血流速度(678.46±45.38)μm/s,B组血流速度为(423.78±51.21)μm/s显著降低(P<0.01),血流流态从线流改变为线粒流;D组血流速度为(663.49±51.46)μm/s较B组明显提高(P<0.01),血流流态为线流;D组与C组、D组与A组微循环指标之间无明显差异(P>0.05)。结论腺苷(CPA)可抑制因饮食结构改变而导致的大鼠肥胖发生;并能有效地改善因肥胖症导致的小肠肠系膜微循环障碍。     

共聚焦激光扫描显微镜(MRC600)活体观测家兔大脑皮质内微循环的动物模型制作方法及其应用探讨

目的 :用共聚焦激光扫描显微镜活体观测家兔大脑皮质内微血管构筑及其微循环提供更近似于人类的动物模型。方法 :在开放颅窗的家兔动物模型上 ,荧光素标记血浆 ,罗丹明 6G标记WBC ,用共聚焦激光扫描显微镜活体观测正常状态下家兔大脑皮质内微循环 ,并经图像分析系统测量数据 ,用SAS软件包进行统计学分析。结果 :本研究探索用开放颅窗的家兔动物模型进行大脑皮质微循环的研究取得成功 ,作者认为采用开放颅窗的家兔动物模型使观察大脑皮质的深度达 2 5 0～ 30 0 μm ,对大脑皮质内微血管构筑及微循环进行活体观测 ,可进行连续断层扫描 ,或在同一层面进行连续定位扫描监测 ,所摄取图像经监视器及计算机摄入并存盘待分析 ,用图像分析系统进行观测血管口径 ,血流速度 ,血液流态 ,白细胞 ,红细胞运动等微循环指标 ,也可用标准Bio Radthruview软件三维重建 ,观察各种血管形态 ,研究大脑皮质微血管构筑。结论 :开放颅窗的家兔动物模型是更近似于人类的动物模型 ,适合用于脑血管疾病发病机理的研究     

微循环荧光造影的安全性及其控制

用围堤式颅窗软脑膜微循环观察方法探讨了微循环荧光造影的安全性。发现：５０Ｗ超高压汞灯的激发光（波长峰值４９０ｎｍ）照射９０ｍｉｎ对血管内皮和平滑肌均有损伤作用。可使微动脉对乙酰胆碱和硝普钠的扩张反应减弱（血管内径变化分别由３７．５％±７．９％降至２３．８％±１１．９％，由４１．１％±２０．８％降至３６．７％±１１．１％，（Ｐ＜０．０５）。单独注射荧光素钠对血管反应性无影响。在激发光持续照射下注射５％荧光素钠０．２ｍｌ进行微循环荧光造影６次（１次／１５ｍｉｎ），血管明显损伤，微动脉对乙酰胆碱和硝普钠的扩张反应分别由４３．５％±１６．９％降至２２．０％±１３．３％，５５．４％±１７．９％降至２５．１％±１４．０％，Ｐ＜０．０５，且伴有严重的血栓形成。认为：控制激发光照射时间以及荧光素钠的浓度和剂量，可以防止上述损伤的发生。     

烟碱对大鼠脑微循环中白细胞运动的影响

目的 :观察烟碱对大鼠脑微循环中白细胞运动状态的影响。方法 :采用围堤式颅窗直视大鼠大脑软脑膜微循环 ,若丹明 6G标记循环血白细胞 ,微循环仪观察软脑膜微血管 (直径 2 5～ 40 μm ,长度 10 0μm)内白细胞的运动状态。结果 :烟碱能浓度依赖性的运动大鼠脑微血管内白细胞在内皮表面的滚动和粘附 ,预先皮下注射烟碱受体拮抗剂美加明可使滚动和粘附的白细胞分别降至 14 .2± 1.1个和 1.3± 0 .7个 (对照组为 10 .2± 1.2个 )。抗E 选择素单抗能明显阻断烟碱依赖所至的白细胞滚动 ,使滚动白细胞数目从 14 .2± 1.7个减为 2 .8± 0 .8个 ,而抗αvβ3整合素抗体能使粘附的白细胞数目从 10 .6± 1.0个降至 3 .8± 1.3个。结论 :烟碱可改变大鼠脑膜微循环中白细胞的运动状态 ,使白细胞在血管内皮表面滚动或粘附于其表面 ;烟碱的作用与激活脑烟碱受体有关 ;E 选择素介导烟碱引起的白细胞滚动 ,而αvβ3整合素则与烟碱引起的白细胞与血管内皮的粘附有关。     

复苏液体温度对失血性休克兔微循环的影响

目的 :观察输注不同温度液体时失血性休克模型兔微循环变化的特点 ,探讨液体复苏时不同温度液体对改善微循环、提高抗休克疗效的作用。方法 :新西兰雄兔 3 0只 ,随机分为 4组制作休克模型 ,休克模型稳定 3 0min后按相同速度相同液量分别给予低温 ( 10 .7± 1.6℃ )、常温 ( 2 0 .6± 1.3℃ )及温热 ( 3 9.5± 1.3℃ )平衡液和自体血 ;在休克前、休克及液体复苏 1h、2h和 4h监测球结膜微循环血流流态、血管口径、毛细血管数目变化。结果 :⑴各组流态随着液体输注逐渐改善 ,温热组流态恢复明显早于其他两组。⑵温热组在液体复苏 1h、2h和 4h的血管管径均明显大于其他两组 ,组间相比有显著性差异 (P <0 .0 5 )。⑶低温组在液体复苏 1h和 2h血管数目明显减少 ,常温组和温热组血管数目均呈逐步增加趋势。结论 :输注温热液体可加快血流速度 ,扩张局部毛细血管 ,减少血管数目的下降 ,从而改善微循环障碍 ,提高休克后液体复苏的效果     

增龄与血流动力学、血液流变学、微循环学变化规律的探讨

目的探讨增龄与血流动力学、血液流变性、微循环的变化规律。方法1705例健康人按年龄分组 ,分别测量不同年龄段颈总动脉血流量 ,血流速度 ,血管口径 ,血管壁波动范围 ,血液流变学指标的变化及甲襞微循环变化的各项指标。结果青壮年组与老年组比较血流动力学各项指标均有显著性差异 ;血液流变学及甲襞微循环各项指标均随增龄有明显变化。结论血流动力学、血液流变性、微循环的变化与增龄密切相关。     

刺激中缝背核观察尼莫地平及颈交感神经对家兔脑皮质微血流的影响

目的 :探讨电刺激兔中缝背核 (DRN)对家兔脑皮质微血流的影响及其机理。方法 :应用氢清除法测定局部脑组织血流 (rCBF)及观测软脑膜血管微循环。结果 :电刺激DRN后脑皮质rCBF减少 44 .2 % (P<0 .0 1) ,软脑膜微动脉管径缩小 ,血流速度减慢 ,而尼莫地平可取消其作用。切断颈交感神经后再刺激DRN ,rCBF减少 15 .8% (P <0 .0 5 )。结论 :电刺激DRN可导致脑皮质微动脉收缩 ,局部血流减少。尼莫地平可解除脑皮质微血管痉挛。切断颈交感神经有降低rCBF的作用。     

Patterns of vascular sprouting in the postnatal development of the cerebral cortex of the rat

Light microscopic histochemistry for alkaline phosphatase was employed in a study of the development of vascular sprouting, with respect to time and distribution, in the rat cerebral cortex. Sprouts were counted in the full thickness of the cerebral cortex at each day from birth to 21 days of age. Several distinct bursts of sprouting activity were observed at specific times and levels of cortex. From birth to 4 days of age, sprouting was intense in the superficial third of the cortex. At 7 to 8 days, a burst of sprouting was found which was greatest in the middle third. Additional bursts of sprouting appeared at 10 and 14 days. Developing vessels with characteristics of arteries, capillaries, or sprouts were alkaline-phosphatase positive, while veins were not. It is concluded that alkaline phosphatase is a useful marker for identification of both mature and immature vasculature, as it reveals patent and nonpatent vessels, and the sprouts which are precursors of the mature vascular bed. New vessels developing in the cortex arise mainly from blind sprouts of capillaries, evidently in response to the metabolic demands imposed by the maturational process. At birth, the majority of intracortical vessels are capillaries. By 10 days of age, most perforating vessels from the surface have taken on arterial or venous characteristics. The findings are discussed in connection with morphological and biochemical differentiation and the pattern of vascularization in the mature cerebral cortex.     

Structural alterations in the human brain in acute alcohol intoxication

Various regions of the brain were studied in 14 patients who suddenly died and in 20 patients who died from ethanol intoxication. Severe circulatory disorders with pronounced vascular pathology, blood diseases, degenerative and necrotic neurocytic changes were shown to develop in ethanol intoxication. The area of neurocytes in the hemispheric cortex, thalamus, and cerebellum reduced due to the death of some of them. In the medulla, they were found to be more resistant to ethanol. The diameter of capillaries in the studied regions of the brain decreased due to the fall in cerebral arterial tonicity, the number of these vessels on the standard area increased, which is due to the compensatory dilatation of reserve capillaries.     

An integrative hypothesis concerning the pathogenesis and progression of Alzheimer''s disease

Observations, in Alzheimer's disease, in the pattern of nerve cell damage and loss, the pathology, microchemistry and immunology of senile plaques and neurofibrillary tangles and alterations in blood vessels are drawn together into a hypothesis that attempts to explain the pathogenesis and progression of the disorder. At the heart of this hypothesis lies a defect in blood brain barrier function and/or structure within the cerebral cortex and this defect may be the cause of the cerebral vessel amyloidosis common in many patients with Alzheimer's disease. Age-related alterations in blood brain barrier allow for damage to nerve terminals and limited formation of senile plaques within cerebral cortex; neurofibrillary tangles are formed within cortical and subcortical nerve cells which project to or near damaged vessels/senile plaques. Uptake of “neurotoxin” at affected terminals and retrograde transport to perikarya causes neurofibrillary tangles to be formed; their accumulation leads to perikaryal changes culminating in cell death and loss. Loss of cells in cortically projecting areas of subcortex such as nucleus basalis, locus caeruleus and dorsal raphe, which terminate on cerebral vessels, causes further blood brain barrier dysfunction, new plaque formation and continued cell loss in cortex and subcortex. Once started, such a process could be self-perpetuating and the initial site of damage could lie within the amygdala/hippocampus with putative pathogenic agent accessing the brain via the olfactory pathways.     

Protease nexin-1. Localization in the human brain suggests a protective role against extravasated serine proteases.

Protease nexin-1 (PN-1) is a potent thrombin inhibitor that is identical to the glia-derived neurite-promoting factor or glia-derived nexin. Here we report immunocytochemical studies of adult human cerebral cortex that revealed the presence of strong immunoreactivity for PN-1 in capillaries and in the smooth muscle cells of arteries and arterioles. Expression of PN-1 was also abundant in astroglial processes in the parenchyma and in perivascular astroglial endfeet of human cerebral cortex. In situ hybridization with an 35S-labeled RNA antisense probe for PN-1 resulted in significant labeling of astrocytes and blood vessels. Because thrombin is known to cause retraction of neurites and modification of astrocytic morphology at low concentrations, PN-1 around blood vessels may play a major protective role against extravasation of thrombin and possibly other serine protease into the human brain.