钙分布异常对烧伤早期心肌力学障碍的影响

目的探讨烧伤后早期心肌损伤的机理。方法应用 Ca~(2 )细胞化学探针及 X 线电子探针显微分析测定了烧伤后心肌细胞亚细胞 Ca~(2 )定位、定量变化,心肌力学及心肌组织能量代谢变化。结果烧伤后1小时心肌细胞胞浆 Ca~(2 )急剧升高,且先于线粒体 Ca~(2 )增加;伴心肌收缩、松弛能力下降,室壁应力增加。心肌组织 ATP、能量负荷在伤后6～12小时显著低于对照组。结论烧伤后心肌细胞钙异常分布可能是引起心肌肌原纤维过强收缩.心肌松弛力降低的主要原因之一。     

严重烧伤早期心肌收缩性与钙转运功能变化

目的研究烧伤早期心肌肌浆网（ＳＲ）钙转运功能变化，探讨其在烧伤后心肌收缩功能下降发病中的作用。方法采用３０％ＴＢＳＡⅢ度烧伤大鼠模型，离体心脏灌流，测定伤前及伤后心肌室内压最大变化速率（±ｄｐ／ｄｔｍａｘ）变化，制备心肌肌浆网，应用微孔滤膜过滤技术测定心肌ＳＲ４５Ｃａ２＋转运功能改变。结果与对照组相比，烧伤组左心室±ｄｐ／ｄｔｍａｘ明显降低（Ｐ＜０．０１），心肌ＳＲＣａ２＋－ＡＴＰａｓｅ活性及ＳＲ４５Ｃａ２＋摄取初速度、摄取容量均明显降低（Ｐ＜０．０１），偶联率比对照值大幅度下降。结论烧伤后早期心肌肌浆网Ｃａ２＋转运功能严重障碍，其是烧伤后心肌收缩功能降低的重要因素之一。     

烧伤后大鼠肌组织唾液酸含量的变化

利用大鼠３０％Ⅲ度烧伤模型，探讨了烧伤大鼠心肌组织唾液酸含量的变化。同时还观察了心肌组织三磷酸腺苷酶活性和Ｃａ＾２＋含量改变。结果表明：烧伤后大鼠心肌组织唾液酸显著降低，伤后３小时仅为对照组的５８．８％，同时心肌组织Ｎａ＾＋，Ｋ＾＋－ＡＴＰａｓｅ，Ｍｇ＾２＋－ＡＴＰａｓｅ和Ｃａ＾２＋－ＡＴＰａｓｅ活性降低，而Ｃａ＾２＋含量明显升高。     

大鼠烧伤后心肌局部肾素-血管紧张素系统的改变

目的观察烧伤早期心肌局部肾素血管紧张素系统（ＲＡＳ）变化及其对心肌肌浆网（ＳＲ）钙运转功能的影响,探讨烧伤早期心功能障碍的发病机制。方法大鼠随机分为对照组（８只,不予致伤）,烧伤组（４０只,致３０％Ⅲ度烧伤）,治疗组（４０只,Ｌｉｓｉｎｏｐｒｉｌ灌胃３天后致３０％Ⅲ度烧伤）,测定烧伤前（对照组）及烧伤后３,８,２４ｈ左心功能变化,心肌组织血管紧张素转换酶（ＡＣＥ）活性,血管紧张素Ⅱ（ＡⅡ）及钙离子（Ｃａ２＋）含量变化,测定心肌ＳＲＣａ２＋ＡＴＰａｓｅ活性,及ＳＲＣａ２＋运转功能的变化。结果烧伤组大鼠左心室内压变化最大速率（±ｄｐ／ｄｔｍａｘ）明显降低,心肌组织ＡＣＥ活性、ＡⅡ及Ｃａ２＋含量显著增加,心肌ＳＲＣａ２＋ＡＴＰａｓｅ活性降低,ＳＲＣａ２＋摄取减少。治疗组预防性给予ＡＣＥ抑制剂Ｌｉｓｉｎｏｐｒｉｌ可显著降低烧伤后心肌组织ＡＣＥ活性,减少ＡⅡ产生,Ｃａ２＋含量降低,增加ＳＲＣａ２＋ＡＴＰａｓｅ活性,ＳＲＣａ２＋摄取增加,左心室功能明显改善。结论烧伤早期心肌局部ＲＡＳ迅速激活,抑制ＳＲＣａ２＋运转,可能是心肌ＲＡＳ促进烧伤早期心功能障碍的作用机制之一。     

烧伤后大鼠心肌组织唾液酸含量的变化

利用大鼠３０％Ⅲ度烧伤模型，探讨了烧伤大鼠心肌组织唾液酸含量的变化，同时还观察了心肌组织三磷酸腺苷酶（ＡＴＰａｓｅ）活性和Ｃａ（２＋）含量改变。结果表明：烧伤后大鼠心肌组织唾液酸显著降低，伤后３小时仅为对照组的５８．８％。同时心肌组织Ｎａ＋、Ｋ＋－ＡＴＰａｓｅ，Ｍｇ２＋－ＡＴＰａｓｅ和Ｃａ２＋－ＡＴＰａｓｅ活性降低，而Ｃａ２＋含量明显升高。提示：唾液酸含量与心肌膜结构和功能有密切关系。组织唾液酸含量的减少可能是造成烧伤后能量代谢紊乱，ＡＴＰａｓｅ功能降低以及钙超载的重要因素之一。     

丙酮酸提高缺血再灌注心肌收缩功能的作用

缺血再灌注可引起同收缩功能的降低。丙酮酸能通过增加心肌细胞磷酸化电位，降低Ｃａ＾２＋超载，增强肌浆网对Ｃａ＾２＋的摄取和释放，减少无机磷酸盐对心肌收缩的抑制使缺血再灌注心肌收缩功能提高。     

严重烧伤早期心肌收缩性与钙转运动能变化

研究烧伤早期心肌肌浆网钙转运动能变化，探讨其在烧伤后心肌收缩功能下降发病中的作用。方法 采用３０％ＴＢＳＡⅢ度烧伤大鼠模型，离体心脏灌流，测定伤前及伤后心肌室内压最大变化速度变化，制备心肌肌浆网，应用微孔滤膜过滤技术测定心肌ＳＲ＾４５Ｃａ＾２＋转运活性及ＳＲ＾５Ｃａ６２＋摄取初速度，摄取容量均明显降低，偶联率比对照值大幅度下降。     

烧伤小鼠活化T细胞内游离钙浓度、蛋白激酶C活性的变化及意义

采用ＴＢＳＡ１０％Ⅲ度烧伤小鼠模型探讨了烧伤后小鼠活化Ｔ细胞内游离钙浓度（［Ｃａ２＋］ｉ）蛋白激酶Ｃ（ＰＫＣ）活性的变化及其同Ｔ细胞功能之间的关系。结果显示，烧伤后活化Ｔ细胞内［Ｃａ２＋ｉ］降低，ＰＫＣ活性下降，且这一变化同烧伤小鼠Ｔ细胞白介素２（ＩＬ－２）ｍＲＮＡ、ＩＬ－２受体α（ＩＬ－２Ｒα）ｍＲＮＡ水平降低，ＩＬ－２生成减少，ＩＬ－２Ｒα表达受抑，Ｔ淋巴细胞转化降低密切相关。钙离子导入剂Ａ２３１８７及ＰＫＣ激活剂ＴＰＡ在体外可分别提高烧伤小鼠活化Ｔ细胞内［Ｃａ２＋］ｉ、ＰＫＣ活性至正常对照水平，也可明显提高烧伤小鼠Ｔ细胞ＩＬ－２及ＩＬ－２Ｒα的基因表达水平，但不能使之恢复正常。提示活化Ｔ细胞内［Ｃａ２＋］ｉ、ＰＫＣ活性降低是导致烧伤后Ｔ细胞功能受抑的原因之一。     

异丙酚和硫喷妥钠对心肌细胞内游离Ca^2＋浓度的影响

目的 观察异丙酚和硫喷妥钠对心肌细胞内游离Ｃａ＾２＋浓度的影响，以探讨静脉麻醉药对心肌细胞内游离Ｃａ＾２＋的作用及其机制。方法 心肌细胞分离培养７～９天，以Ｆｕｒａ－２／ＡＭ荧光指示剂负载后，实验组Ａ加入实验用药孵育１０分钟进行Ｃａ＾２＋测定，实验组Ｂ：加入实验用药１０分钟后，加ＫＣｌ４０ｍｍｏｌ／Ｌ１分钟后进行Ｃａ＾２＋测定。结果 临床剂量的异丙酚和硫喷妥钠对静息心肌细胞内Ｃａ＾２＋浓度无明显影     

烫伤后心肌线粒体呼吸链变化对心肌收缩性的影响

目的 观察重度烧伤对心肌细胞线粒体呼吸链的影响，探讨烧伤后心肌收缩功能下降及心车出量减少的机理。方法 采用３０％Ⅲ度烫伤大鼠模型，用差速离心分离心肌细胞线粒体，以氧电极技术和差光谱法测定琥珀酸呼吸链和还原型辅酶Ｉ（ＮＡＤＨ）呼吸链的电子传递活性，同时监浊心肌力学的变化。结果 烫伤后２ｈＮＡＤＨ－细胞色素Ｃ还原酶及细胞色素氧化酶即低于对照组，烫伤后４ｈ琥珀酸－Ｃｏ．Ｑ还原酶、ＮＡＤＨ－Ｃｏ．Ｑ还原酶     

钙分布异常对烧伤早期心肌力学障碍的影响

OBJECTIVE: To investigate the effect of abnormal Ca2+ distribution on impairment of myocardial mechanics in the early stage of thermal injury. METHODS: Calcium (Ca2+) changes were observed within subcellular distribution in situ in rat heart with calcium cytochemical probe and electron probe microanalysic technique. Meanwhile, myocardial mechanics and energy metabolic changes were investigated after thermal injury. RESULTS: The results demonstrated that levels of cytoplasmic Ca2+ in cardiomyocytes increased at 1 hour, followed by enhanced mitochondrial Ca2+ at 3 hour after burn injury. Parallel to the changes in Ca2+, there were decrease of myocardial contraction, relaxation capacity and increase of ventricular wall stiffness in burned rats. A lower level of heart energy changes was observed from 6 to 12 hours, compared with control group. CONCLUSION: The results indicate that subcellular Ca2+ abnormal distribution in myocardium caused by burn injury may be associated with rigor contraction and decreased relaxation of myocardium.     

内质网应激反应在严重烧伤大鼠心肌细胞凋亡中的作用

目的内质网应激反应(endoplasmic reticulum stress,ERS)介导的凋亡是真核细胞重要凋亡途径之一,通过观察严重烧伤大鼠心肌ERS不同通路蛋白表达变化,探讨其在心肌细胞凋亡中的可能作用。方法雄性7周龄Wistar大鼠64只,体重200～220 g;随机分为两组,每组32只。实验组大鼠背部制备30%体表面积Ⅲ度烫伤;对照组制备假伤模型。伤后1、4、7、14 d两组各处死8只大鼠取心肌组织,透射电镜观察心肌超微结构变化,TUNEL法检测心肌细胞凋亡,Western blot检测ERS相关蛋白,如葡萄糖调节蛋白78(glucose regulated protein 78,GRP 78)、C/EBP同源蛋白(C/EBP-homologous protein,CHOP)、半胱氨酸天冬氨酸蛋白酶12(Caspase 12)剪切体表达变化。结果大鼠均存活至实验结束。透射电镜观察示实验组大鼠心肌细胞呈凋亡改变。伤后各时间点实验组心肌细胞凋亡指数均明显高于对照组(P<0.05),伤后1、4、7 d凋亡指数逐渐升高,14 d时下降,各时间点间比较差异均有统计学意义(P<0.05)。实验组心肌细胞GRP78、CHOP及Caspase 12剪切体蛋白表达持续升高,其中各时间点GRP 78及Caspase 12剪切体表达均较对照组显著升高,差异有统计学意义(P<0.05);除伤后1 d外,其余各时间点实验组CHOP蛋白表达均较对照组升高(P<0.05)。结论严重烧伤后大鼠心肌发生ERS,其中CHOP、Caspase 12介导的凋亡通路活化,ERS可能是心肌细胞凋亡的途径之一。     

烫伤后心肌线粒体呼吸链变化对心肌收缩性的影响

目的观察重度烧伤对心肌细胞线粒体呼吸链的影响,探讨烧伤后心肌收缩功能下降及心输出量减少的机理。方法采用３０％Ⅲ度烫伤大鼠模型,用差速离心法分离心肌细胞线粒体,以氧电极技术和差光谱法测定琥珀酸呼吸链和还原型辅酶Ｉ（ＮＡＤＨ）呼吸链的电子传递活性,同时监测心肌力学的变化。结果烫伤后２ｈＮＡＤＨ细胞色素Ｃ还原酶及细胞色素氧化酶即低于对照组,烫伤后４ｈ琥珀酸Ｃｏ．Ｑ还原酶、ＮＡＤＨＣｏ．Ｑ还原酶、琥珀酸Ｃｙｔ．Ｃ还原酶也明显低于对照组。同时伴心肌收缩功能的下降。但随烫伤时间的延长（烫伤后６ｈ）呼吸链电子传递活性及心肌力学的变化无继续降低。结论重度烧伤后心肌细胞线粒体呼吸链电子传递活性受到全面损伤,致使心肌氧利用发生障碍,可能是心肌收缩功能下降、心输出量减少的原因之一。     

Cardiovascular distribution of the calcium sensing receptor before and after burns

Due to up-regulation of the parathyroid gland calcium-sensing receptor (CaR), burned children have hypocalcemic hypoparathyroidism, and decreased myocardial contractility. Our aim was to localize the CaR in the heart and measure receptor density changes due to burns. Heart and aorta samples from sheep subjected to 40% burn or sham conditions were probed for CaR via fluorescence microscopy. CaR was localized to endocardial endothelium, myocardial microvasculature, and fibroblasts and vessels of the aortic adventitia. CaR was not found in cardiomyocytes or smooth muscle cells. No differences in density of CaR or beta-adrenergic receptors were noted. No differences in CaR distribution were seen in the myocardium or aorta, in contrast to the parathyroid where burn injury up-regulates CaR. We suggest that CaR has a local, tissue-specific role, and functions in vascular calcium sensing for intravascular calcium deposition or regulation of other calcium channels after trauma or burn.     

伤后即行切痂对烧伤大鼠心肌损伤的防治作用

目的探讨早期一次性切痂对烧伤后心肌损伤的防治作用。方法建立３０％ＴＢＳＡⅢ度烧伤大鼠立即切痂模型,动物随机分为正常对照组、未切痂组和切痂组,于伤后１,３,６,１２和２４ｈ检测血浆肌钙蛋白Ｔ（ＴｎＴ）和肿瘤坏死因子（ＴＮＦ）等指标。结果烧伤后３ｈ血浆ＴｎＴ即显著升高,伤后６ｈ血浆ＴＮＦ显著高于伤前,心肌组织中ＴＮＦ也在伤后１２ｈ显著升高。未切痂组与切痂组比较,伤后１～３ｈ未切痂组ＴｎＴ、ＴＮＦ略低于切痂组,烧伤６ｈ后,未切痂组ＴｎＴ显著高于切痂组,烧伤１２ｈ后,未切痂组ＴＮＦ显著高于切痂组。ＴＮＦ与ＴｎＴ存在显著正相关关系。结论ＴＮＦ是引起烧伤后心肌损伤的重要因素,且与心肌损伤程度密切相关。伤后即行一次性切痂可以减少炎症介质的生成和释放,这可能是其对烧伤后并发心肌损伤具有防治作用的机理之一。     

Effect of sialyl Lewis(x) oligosaccharide on myocardial and cerebral injury in the pig

BACKGROUND: Although administration of the sialyl Lewis(x) oligosaccharide may reduce myocardial injury after ischemia-reperfusion, its effect on coronary and cerebral microvascular regulation and its clinical application during cardiac operation have not been examined. METHODS: Pigs were placed on normothermic cardiopulmonary bypass after 30 minutes of left anterior descending coronary artery occlusion. The hearts were then arrested with cold high potassium cardioplegia. After 1 hour the cross-clamp was removed and the pigs were weaned from cardiopulmonary bypass and perfused for an additional 1 hour. CY-1503 (a sodium salt of the sialyl Lewis(x) oligosaccharide, n = 6) was administered before reperfusion. Six other pigs received saline vehicle. Endothelium-dependent relaxation of precontracted coronary and brain arterioles (70 to 180 microm) to adenosine 5'-diphosphate and endothelium-independent relaxation to sodium nitroprusside were studied in vitro with videomicroscopy. Control values were obtained from uninstrumented pigs. Myeloperoxidase activity in the myocardium and brain was measured to quantify neutrophil infiltration. Cardiac function and perfusion were assessed by left ventricular systolic pressure, maximum rate of increase of left ventricular pressure, left anterior descending coronary artery blood flow and percent segmental shortening, and cerebral vascular resistance, internal carotid artery blood flow, and the constitutively expressed and inducible isoform of nitric oxide synthase mRNA were measured. RESULTS: The impaired myocardial contractile function after ischemia and cardioplegia was not improved by administration of CY-1503. The reduced endothelium-dependent relaxation responses of coronary and brain arterioles during ischemia followed by cardioplegia and cardiopulmonary bypass were improved with CY-1503, but the altered pattern of organ perfusion was not improved. Myeloperoxidase activity was increased in the heart after ischemia-cardioplegia and in the brain after cardiopulmonary bypass. CY-1503 reduced myeloperoxidase activity in both the myocardium and in the brain. Expressions of myocardial inducible isoform or constitutively expressed nitric oxide synthase were not altered in the heart. CONCLUSIONS: Although the sialyl Lewis(x) oligosaccharide does reduce neutrophil infiltration and endothelial injury in the coronary and cerebral microcirculation after cardiopulmonary bypass, it does not have significant beneficial acute effects on organ perfusion or function in the myocardium or brain.     

烧伤合并内毒素血症TNFαmRNA原位表达与早期心肌损害的实验研究

目的观察TNFαmRNA及其蛋白在心肌细胞的原位表达,探讨烧伤合并内毒素血症早期心肌损害的可能机制。方法采用20％TBSAⅢ度烧伤复合内毒素血症多脏器损害模型,时相点设为伤后0.5、1、3、6、12、24和48h。将178只大鼠随机分为烧伤复合内毒素注射组(烧注组)、单纯烧伤(单烧组)、单纯内毒素注射组(单注组)和正常对照组。采用光、电镜观察,ELISA及免疫组化,原位杂交染色,等观察大鼠心肌形态功能变化、血清TNFα含量变化、TNFαmRNA及其蛋白在心肌细胞的定位及分布。结果烧注组致伤早期心肌出现一系列损害性改变,如波浪变性、收缩带形成、肌纤维断裂和灶性胞浆内溶解等。左室收缩压(LVSP)及室内压最大变化速率(±dp/dtmax)显著下降(P＜0.01)。血清TNFα水平于1h明显升高(P＜0.01),3～6h达高峰。TNFαmRNA主要定位于心肌细胞和部分炎细胞。而单因素组病变程度轻,心肌损害不明显,血清TNFα峰值滞后以及心肌组织TNFαmRNA表达相对较弱。结论烧伤合并内毒素血症状态下,心肌本身可表达TNFαmRNA及其蛋白,并可能作为机体TNFα产生来源之一,参与早期心肌结构与功能损害的发生发展。     

腺苷预处理对体外循环术后心肌肌钙蛋白变化的影响

目的 探讨腺苷预处理对心脏直视手术的心肌保护效果。方法 ３０例择期心瓣膜置换术患者随机分成实验组和对照组，每组１５例。实验组在术前行腺苷预处理。分别于转流前、主动脉阻断３０分钟和６０分钟、主动脉开放后３０分钟及术后２４小时采血测定心肌肌钙蛋白Ｔ（ｃＴｎＴ）、心肌酶谱和丙二醛。结果 腺苷预处理ｃＴｎＴ和心肌酶外漏明显减少，丙二醛生成减少。结论 腺苷预处理能减轻心肌肌缺血再灌注损伤。