夏至草生物碱对失血性休克大鼠淋巴微循环的影响

目的 探讨夏至草生物碱（AHL）对失血性休克大鼠淋巴微循环的影响。方法Wistar大鼠16只。随机分成夏至草生物碱组（AHL组）和生理盐水组（NS组，n=8），经颈总动脉放血复制大鼠失血性休克模型．观察AHL对肠系膜淋巴微循环的影响。结果 失血性休克时，肠系膜淋巴微循环出现明显障碍。AHL可明显使肠系膜淋巴管口径扩张，收缩幅度增大，收缩频率加快，收缩性指数升高，其作用显著优于NS组（P〈0．05）。结论 AHL能明显改善失血性休克大鼠的淋巴微循环障碍。     

P物质增强失血性休克大鼠离体淋巴管的泵功能

目的: 建立离体淋巴管灌流技术,观察P物质(SP)对失血性休克(HS)发展进程中淋巴管收缩性的影响。方法: Wistar雄性大鼠随机分为对照组(仅麻醉与手术)和HS组 。各组在相应时点分离胸导管,制备淋巴管条,在3 cmH₂O跨壁压下离体灌流,分别给予从低到高浓度的SP,测量淋巴管收缩末期口径、舒张末期口径、收缩频率(CF)和被动管径,计算收缩幅度(CA)、泵流分数(FPF)和紧张指数(TI)。结果: SP对各组淋巴管的CF、TI和FPF均有提高作用,且随着SP浓度的增加,这种作用也逐渐增强;SP浓度自3×10^-8 mol/L起,将休克2 h和3 h淋巴管的CF、TI和FPF提高至(或超过)实验前对照组水平。同一浓度下,SP对各组淋巴管CA的影响无统计学差异;但随着SP浓度增高,各组淋巴管CA值出现了下降趋势。结论: SP不仅具有增强生理状态下淋巴管泵功能的作用,更重要的是可增强休克各期淋巴管的泵功能。     

失血性休克大鼠淋巴管对去甲肾上腺素反应性的变化

目的:观察失血性休克(HS)大鼠淋巴管对去甲肾上腺素(NE)反应性的变化,探讨淋巴管反应性在休克发病学中的作用。方法:假手术组(sham)和失血性休克组(HS,股动脉放血使血压维持40mmHg)各8只大鼠行胸导管腹段插管,测压,观察在不同时点股静脉注射NE(5μg/kg)前后淋巴管压力的变化;通过微循环录像系统对每组另8只大鼠回肠下段肠系膜淋巴管(ML)活体标本的自主收缩频率(F)、最大收缩口径(a)、最大舒张口径(b)、静态口径(c)连续记录,计算不同时点给予NE前后淋巴管收缩分数(index I)、总收缩活性指数(indexⅡ)、淋巴管动力学指数(LD-index)的变化(用△表示)。结果:HS组自休克30min起对NE的升压反应开始减弱,呈进行性降低,1h-3h间各时点的升压幅度显著低于sham组。HS组ML在休克1h的△F、△indexⅡ、△LD-index以及1.5h、2.h的△F、△index I、△indexⅡ、△LD-index均显著低于sham组,且在这3个时点的△F、△index I、△indexⅡ、△LD-index均显著低于休克前。结论:大鼠淋巴管的反应性在失血性休克发展进程中呈进行性下降,淋巴管低反应性在休克发病学中可能具有重要作用。     

失血性休克时淋巴微循环的变化

本文应用显微电视录像技术,观察大鼠失血性休克时肠系膜微淋巴管(MLV)的变化,旨在探讨休克时淋巴微循环的变化及其意义。结果发现,失血性休克时MLV静态口径进行性缩小。休克早期,MLV自主收缩性无明显变化,内皮细     

一氧化氮在休克大鼠离体淋巴管对P物质反应性中的作用

目的: 应用离体淋巴管灌流技术,观察一氧化氮(NO)在失血性休克(HS)大鼠离体淋巴管对P物质(SP)反应性双相变化中的作用。方法: Wistar雄性大鼠随机分为对照组(仅手术)和休克组(复制HS模型后分为shock 0.5 h、shock 2 h组)。在相应时点分离胸导管,制备淋巴管条,3 cmH₂O跨壁压下行离体灌流,应用一氧化氮合酶(NOS)工具药分别孵育shock 0.5 h和shock 2 h的淋巴管。分别给予从低到高浓度的SP,测量淋巴管收缩末期口径、舒张末期口径、收缩频率(CF)和被动管径,计算收缩幅度(CA)、泵流分数(FPF)和紧张指数(TI),以给予SP前后淋巴管的CF、TI、CA和FPF的差值ΔCF、ΔTI、ΔCA和ΔFPF评价淋巴管对SP的反应性。结果: NO供体L-Arg可显著降低shock 0.5 h淋巴管对多个SP浓度点的ΔCF、ΔTI与ΔFPF;可溶性鸟苷酸环化酶抑制剂ODQ可显著抑制L-Arg的作用,在某些SP浓度点上,使ΔCF、ΔTI和ΔFPF显著高于shock 0.5 h+L-Arg组,ΔCF和ΔFPF高于对照组水平。NOS抑制剂L-NAME可提高shock 2 h淋巴管对多个SP浓度点的ΔCF、ΔTI与ΔFPF,且高于对照组水平;shock 2 h淋巴管与L-NAME和磷酸二酯酶抑制剂氨茶碱(AP)同时孵育后,在SP为1×10^-8 mol/L和3×10^-8 mol/L时,AP显著抑制了L-NAME的作用,使ΔCF、ΔTI与ΔFPF明显降低。结论: NO参与了休克淋巴管反应性的双相调节,其机制可能是通过环鸟苷酸实现的。     

肌球蛋白轻链激酶在失血性休克大鼠离体淋巴管收缩性双相变化中的作用

目的: 探讨肌球蛋白轻链激酶(MLCK)在失血性休克(HS)大鼠离体淋巴管收缩性双相变化中的作用机制。方法: Wistar雄性大鼠随机均分为对照组和HS组(复制HS模型,分为HS 0 h、0.5 h、1 h、2 h和3 h亚组),留取胸导管组织,检测磷酸化MLCK(p-MLCK)含量;制备对照、HS 0.5 h与2 h组的淋巴管条,采用离体淋巴管收缩性观察技术,观察MLCK抑制剂ML-7和激动剂P物质(SP)对HS 0.5 h及2 h淋巴管收缩频率(CF)、收缩末期直径、舒张末期直径和被动直径的影响,计算淋巴管紧张性指数(TI)、收缩幅度(CA)和泵流分数(FPF),评价淋巴管收缩性。结果: HS 0h和0.5 h淋巴管组织p-MLCK蛋白显著高于对照组;随着休克发展,p-MLCK含量逐渐降低。在1、3、5 cmH₂O等多个跨壁压下,HS 0.5 h组淋巴管的CF、TI和FPF均显著高于对照组,ML-7可显著下调这些指标,SP则可明显降低ML-7的作用,使之恢复至HS 0.5 h水平;HS 0.5 h组淋巴管的CF、TI和FPF均显著低于对照组,SP可显著上调这些指标,ML-7则可显著降低SP的作用。HS 0.5 h与2 h离体淋巴管CA与对照组相比无显著变化,SP可降低HS 2 h淋巴管的CA,ML-7可抑制该作用,但二者对HS 0.5 h无明显作用。结论: MLCK作为影响淋巴管平滑肌细胞收缩的关键酶,参与了HS发展进程中淋巴管收缩性的双相调节。     

失血性休克大鼠淋巴管低反应性的钙敏机制

目的:观察失血性休克(HS)大鼠离体淋巴管对去甲肾上腺素(NE)反应性以及钙敏感性的变化,探讨淋巴管低反应性的钙敏机制。方法:Wistar雄性大鼠随机均分为sham组(仅手术)和HS组(复制HS模型,分为休克1 h、休克2 h亚组),制备胸导管环(每组均n=48)。采用离体淋巴管张力测定技术,观察淋巴管环对NE反应性以及钙敏性[梯度Ca2+与血管紧张素Ⅱ(AngⅡ)和胰岛素(Ins)分别孵育]变化。结果:与sham组相比,HS1 h组、HS 2 h组大鼠离体淋巴管对NE反应的量效曲线以及HS 2 h组淋巴管对Ca2+的量效曲线明显右移,对NE多个浓度的反应性以及不同Ca2+浓度的收缩力、最大收缩力(Emax)、亲和力指数(pD2)均显著降低。HS大鼠离体淋巴管环与钙敏感性增强剂AngⅡ孵育后,对NE的反应性以及钙敏感性均显著升高,但仍低于sham组;与钙敏感性抑制剂Ins孵育后,对NE的反应性以及钙敏感性均显著降低。结论:HS大鼠离体淋巴管的低反应性与钙失敏有关,这是休克时淋巴管收缩性降低的机制之一。     

自发性高血压幼鼠淋巴微循环自律运动特征

目的:观察幼龄自发性高血压大鼠(SHR)发病早期淋巴微循环的自律运动特征。方法:手术暴露3周龄雄性SHR(SHR组,n=11)和Wistar大鼠(Wistar组,n=11)肠系膜集合淋巴管,采用活体显微录像设备连续视频录像,使用Vastrack自律运动跟踪技术对视频录像进行动态测量分析,比较两组大鼠肠系膜集合淋巴管自律运动收缩频率、相对振幅、收缩时长、舒缩时长、收缩振幅、舒张振幅、收缩速度、舒张速度、收缩/舒张时长比、收缩分数和收缩活力指数的差异。结果:SHR组大鼠淋巴微循环自律运动的相对振幅、收缩振幅、舒张振幅、收缩时长、舒张时长、收缩速度、舒张速度和收缩分数较Wistar组大鼠轻度降低,收缩频率、收缩/舒张时长比和收缩活力指数较Wistar组大鼠小幅上升,但差异均无统计学意义(P0.05)。结论:自发性高血压早期幼鼠集合淋巴管自律运动特征未见显著改变,提示其淋巴微循环尚未发生明显功能紊乱。     

严重烧伤休克大鼠淋巴微循环、细胞因子及淋巴管内皮细胞超微结构的变化

目的研究严重烫伤休克期大鼠淋巴微循环及淋巴液中肿瘤坏死因子-α（TNF—α）、白细胞介素石（IL-6）、白细胞介素-8（IL-8）水平的变化，观察肠系膜淋巴管内皮细胞超微结构变化。方法将Wistar大鼠随机分为A烧伤补液组、B烧伤非补液组和C对照组。在A组和B组动物背部造成30％TBSAⅢ度烫伤，A组补液抗休克，B、C组不予补液。观察大鼠肠系膜淋巴管伤后6、24、48h的运动变化，计算淋巴管收缩频率，检测淋巴液TNF—α、IL-6、IL-8水平的变化。利用扫描电镜观察肠系膜淋巴管内皮细胞超微结构变化。结果烧伤休克淋巴管收缩频率降低，电镜下见肠系膜淋巴管内皮细胞肿胀，内皮细胞连接破坏。淋巴液中TNF-α、IL-6、IL-8的水平升高。与A组比较，B组收缩频率显著降低，淋巴液中TNF—α、IL-6、IL-8的水平显著升高。结论严重烫伤休克大鼠淋巴管扩张，运动减少。肠系膜淋巴管内皮细胞损伤，淋巴液中TNF—α、IL-6、IL-8的水平升高。液体复苏能够改善淋巴循环。     

急性内毒素血症早期大鼠肠系膜淋巴管的动态观察

目的利用活体微循环显微闭路电视系统,研究内毒素作用下肠系膜淋巴管的运动变化,探讨内源性NO对淋巴管的作用.方法Wistar大鼠分三组,于股静脉一次性推注:(1)内毒素(脂多糖,1ipopolysaccharide,LPS);(2)一氧化氮合酶(NOS)抑制剂N-硝基-L-精氨酸甲基酯(L-NAME);(3)LPS及L-NAME.观察注药前和注药后2 h内的肠系膜淋巴管管径、收缩频率等指标.结果(1)LPS组:肠系膜淋巴管管径较注药前扩大,运动频率减少,总收缩活性指数变小;(2)L-NAME组:淋巴管管径变细、运动频率增加、收缩分数变大;(3)LPS L-NAME组:淋巴管管径、运动频率、运动指数2 h内变化不显著.结论内毒素血症早期肠系膜淋巴管扩张、收缩减弱,同时应用L-NAME可抑制该变化,单独应用L-NAME则使淋巴管缩窄、收缩加强,提示NO可能在维持正常淋巴管运动及内毒素血症早期淋巴循环变化过程中起重要作用.     

熊胆冻干粉针剂对失血性休克大鼠肠系膜微循环的影响

目的 :观察熊胆注射液对失血性休克大鼠平均动脉血压 (MABp)和存活时间的影响及其对失血性休克大鼠肠系膜微循环的作用。方法 :将Wistar系失血休克大鼠随机分 2组 :实验组 (BBI组 )静脉滴注 18mg/kg熊胆注射液 36ml/kg ;对照组 (NS组 )给予等容量的生理盐水。分别记录放血前、放血 6 0min、给药抢救 30min、 6 0min时MABp和各微循环指标的动态变化以及存活时间。结果 :(1)休克时各组MABp显著降低 ,BBI组给药后血压回升作用显著 ,与NS组比较给药抢救 30min、 6 0min时分别为P <0 .0 5、P <0 .0 1;存活时间BBI组明显延长 ,与NS组比较P <0 .0 1)。 (2 )在休克时二组肠系膜微血管血液速度均显著变慢 ,从放血前的线流变为粒流、泥流 ,红细胞聚集甚至停流。微血管口径均显著变细 ;微血管活动数均显著减少 ,而给药后微血管血流速度加快 ,微血管流态改善 ,变为粒线流及线粒流 ;微血管口径舒张 ;微血管活动数增加 ,BBI组与NS组比较均有显著性差异 (P <0 .0 5 )。结论 :18mg/kg熊胆注射液对失血性休克大鼠有明显的回升血压作用并延长存活时间 ;有舒张肠系膜微血管 ,改善微循环 ,减轻组织细胞缺血缺氧状态的作用。     

Regional and species differences in vascular reactivity to extracellular potassium

In-vitro vasoreactivity to extracellular potassium (Ko+) was tested in isolated human pial and mesenteric arteries as well as basilar and mesenteric arteries from rabbits and rats. Contractions were induced by stepwise increases in [K+]o and were measured isometrically with a force-displacement transducer, in small-volume organ baths. Significant differences between species as well as between regions were found. The threshold of [K+]o for eliciting contraction in human cerebral arteries in hyperosmotic solutions was 10 mM, in rabbit cerebral arteries 17 mM and in rat cerebral arteries 27 mM. The threshold concentration for contraction in mesenteric arteries was significantly higher compared to cerebral arteries in humans and rabbits, but lower in rats: 20 mM in humans, 26 mM in rabbits and 25 mM in rats. In all species the contractile amplitudes were significantly higher in both cerebral and mesenteric arteries when [K+]o was increased under isotonic conditions in the buffer solution than when hyperosomolality was created. This difference increased with increasing hyperosmolality. In hyperosmotic solutions, the EC50 for [K+]o was lower in cerebral and mesenteric arteries from man than in vessels from rabbit and rat. When the solutions were isotonic, this pattern was seen only in mesenteric arteries. It is concluded that significant species and regional differences in vascular responses to [K+]o exist. Considering that [K+]o is increased in cerebral ischaemia, the observed significantly lower threshold for K+-induced contractions in human cerebral arteries may be of importance, especially in human cerebral ischaemic events.     

Contribution of Na+/Ca2+ exchanger to the regulation of myogenic tone in isolated rat small arteries.

The contribution of the Na+/Ca2+ exchanger to the myogenic vascular tone was examined in rat isolated skeletal muscle small arteries (ASK) with pronounced myogenic tone and mesenteric small arteries (AMS) with little myogenic tone. Myogenic tone was assessed by the vascular inner diameter at transmural pressures of 40 and 100 mmHg. To depress the Na+/Ca2+ exchanger, the extracellular Na+ concentration ([Na+]o) was lowered from 143 to 1.2 mM by substituting choline-Cl for NaCl. The ASK developed significant myogenic tone and constricted further in low [Na+]o. Nifedipine (1 microM) reduced both myogenic tone and low [Na+]o-induced contraction. Because the membrane potential of ASK was not changed by low [Na+]o (-35 +/- 2 mV at 143 mM [Na+]o, -37 +/- 3 mV at 1.2 mM [Na+]o), depolarization-induced Ca2+ influx was not a cause of the low [Na+]o-induced contraction. The AMS did not develop significant myogenic tone. Although low [Na+]o also constricted AMS, the magnitude of constriction was significantly weaker than that in ASK (17 +/- 4 vs. 47 +/- 6%, P < 0.01, at 58 mM Na+). With Bay K 8644, AMS developed myogenic tone, and low [Na+]o-induced constriction was significantly increased. In conclusion, Na+/Ca2+ exchanger may play an important role in regulating myogenic tone, likely via mediating Ca2+-extrusion.     

Effects of gender on intracellular [Ca2+] in rat cardiac myocytes

The present study investigated the effects of gender on intracellular [Ca2+] ([Ca2+]i) in freshly isolated rat cardiac myocytes. Changes in [Ca2+]i in response to varied extracellular [Ca2+], different stimulus frequencies and addition of caffeine and isoprenaline were monitored using fura-2 in both male and female cardiac myocytes. Increasing extracellular [Ca2+] and stimulus frequency resulted in significant increases in peak [Ca2+] and the amplitude of the Ca2+ transient in both male and female cardiac myocytes. However, as extracellular [Ca2+] was raised, peak [Ca2+] and the amplitude of the Ca2+ transient increased significantly more in male than female cardiac myocytes. In addition a significant difference between male and female cells at each stimulus frequency was apparent. The time course of decay of the Ca2+ transient was significantly slower in female cardiac myocytes when compared with male cardiac myocytes, along with significantly slowed times to peak shortening and 50% relaxation, and a reduced extent of shortening. There was no significant difference in the amplitude of caffeine-induced [Ca2+]i responses between male and female cells, however, [Ca2+]i increased more readily in male cells than in female cells when isoprenaline was added. The data demonstrate that, under a variety of conditions, intracellular [Ca2+] rises to higher levels in cardiac myocytes from male as compared to female rats.     

淋巴液对失血性休克大鼠肠系膜微循环变化的影响

大鼠３０只，分为肠淋巴液治疗组及生理盐水对照组，复制重度失血性休克模型后，应用显微电视录像技术观察淋巴液对肠系膜微血管及微淋巴管的作用。结果：治疗组的存活时间显著长于对照组。输入淋巴液后，血压显著回升，肠系膜一、二级细动脉、细静脉口径和微淋巴管的静态口径均恢复正常，流态改善，微淋巴管收缩性恢复正常。提示肠淋巴液可以改善休克时的血液和淋巴循环障碍，对休克具有较好的治疗作用