牛磺酸对严重烧伤大鼠心肌损害的保护作用

目的　观察牛磺酸(Tau)对严重烧伤大鼠心肌损害的作用。　方法　将Wistar大鼠随机分为对照组(10只,不致伤)、烧伤组(60只)和Tau治疗组(60只)。后两组大鼠造成30%TBSAⅢ度烫伤(以下称烧伤),烧伤组伤后常规补液,Tau治疗组伤后腹腔注射Tau400mg/kg.于两组烧伤大鼠伤后1、3、6、12、24、48h检测其血浆中心肌肌钙蛋白T(cTnT)、丙二醛(MDA)的含量以及血浆、心肌组织中肿瘤坏死因子α(TNF- α)、血管紧张素Ⅱ(AngⅡ)的含量、心肌钙离子水平,用透射电镜观察心肌组织形态结构变化,并与对照组的上述指标进行比较。将烧伤组大鼠血浆TNF- α、AngⅡ检测结果分别与cTnT检测结果作相关性分析。　结果　烧伤组大鼠伤后3h起血浆cTnT水平较对照组(0.16±0. 03)μg/L显著升高(P<0. 01), 12h达峰值(6. 32±0. 41)μg/L, 48h仍显著高于对照组(P<0. 01).烧伤组伤后3—48h血浆MDA含量及心肌钙离子水平明显高于对照组(P<0. 01 );伤后6—48h血浆和心肌组织TNF- α含量显著高于对照组(P<0. 01);血浆及心肌组织中AngⅡ水平分别于伤后1—24h、3—24h明显高于对照组(P<0. 01).Tau治疗组上述指标在伤后多数时相点明显低于烧伤组(P<0. 01). 烧伤组大鼠伤后早期心肌肌丝断裂溶解、线粒体肿胀、嵴减少,Tau治疗组心肌组织接近正常。烧伤组     

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。     

Nitrosoglutathione improves blood perfusion and flap survival by suppressing iNOS but protecting eNOS expression in the flap vessels after ischemia/reperfusion injury

BACKGROUND: The effects of nitric oxide (NO) on the microcirculation and free tissue survival remain controversial. With the use of a rat inferior epigastric artery flap as an ischemia/reperfusion injury (I/R) model, we investigated whether exogenous NO donation regulates endogenous NO synthase (NOS) expression in the flap vessels and promotes flap survival. METHODS: Thirty minutes before flap reperfusion, normal saline (1 ml), nitrosoglutathione (GSNO 0.2, 0.6, 3 mg/kg), or N(G)-nitro-L-arginine-methyl ester (L-NAME, 450 mg/kg), was injected intravenously into 20 rats. Total plasma NOx (NO(2)-/NO(3)-) was measured to reflect NO production. Immunohistochemical staining was investigated for the endothelin-1 (ET-1) and NOS isoforms expression on the flap vessels. NOS isoforms expression was evaluated by Western blot. Laser-Doppler flowmetry monitored flap perfusion. Survival areas were assessed by gross examination at 7 days postoperatively. RESULTS: Flap ischemia at 12 hours followed by reperfusion resulted in endothelial cell damage, as demonstrated by induction of iNOS and ET-1 expression in the flap vessels. An optimal dose of nitrosoglutathione (0.6 mg GSNO/kg) significantly increased plasma NOx levels (P=.027) and improved flap perfusion by laser Doppler measurement (P=.014), and increased the flap viability area (P<.001). Additionally, it selectively suppressed iNOS induction, but enhanced eNOS expression and decreased ET-1 deposition in the flap vessels. In contrast, an NOS inhibitor, N(G)-nitro-L-arginine methyl ester, inhibited both iNOS and eNOS expression in the flap vessels, decreased endogenous NOx production, and compromised flap viability. CONCLUSION: This study indicates that intravenous administration of exogenous GSNO can appropriately donate NO to suppress iNOS induction and enhance eNOS expression in pedicle vessels, resulting in better blood perfusion and a higher flap survival after I/R injury.     

硫酸镁对弥漫性脑损伤脑组织的保护作用及机制

目的 探讨硫酸镁对于弥漫性脑损伤脑组织可能的保护机制.方法 依据Marmarou's弥漫性脑损伤动物模型有改进,采用成年健康SD雄性大鼠,体质量325～375 g,共50只.其中,外伤组25只,干预组25只(两组外伤后12、24、48、72 h,1周,每组各5只).干预组应用微泵给予硫酸镁静脉注射治疗,外伤后大鼠自由进食水,按时间段处死大鼠,提取大鼠皮层脑组织,应用实时逆转录.聚合酶链反应(realtime RT-PCR)检测外伤组与干预组不同时间段ET-1 mRNA、iNOS mRNA表达,另取脑组织应用脑组织干湿重比表示脑组织含水量.结果 ET-1 mRNA表达干预组较外伤组干预组降低,应用成组t检验分析方法检验可得:6、12、24、48 h组组间差异有统计学意义(P<0.01),72 h,1周组间比较差异无统计学意(P>0.05).iNOS mRNA表达干预组较外伤组降低,干预组与外伤组相应时间组组间差异有统计学意义(P<0.01).结论 应用微泵静脉注射硫酸镁早期减少了ET-1 mRNA、iNOS mRNA的表达,从而使ET-1、iNOS、NO合成减少,减轻了脑组织缺血缺氧及对脑细胞的毒性,从而使干预组弥漫性脑损伤大鼠脑组织含水量较单纯外伤组弥漫性脑损伤大鼠脑组织含水量减少的原因.     

Effect of uric acid on liver injury during hemorrhagic shock

BACKGROUND: It remains unproven whether nitric oxide (NO) exerts a toxic effect on hepatocytes directly or through the formation of a more toxic compound during hemorrhagic shock (HS). NO reacts at a very high rate constant with superoxide to give peroxynitrite, a potentially toxic molecule. In this study, we investigated whether or not peroxynitrite contributed to tissue injury in the liver during HS. METHODS: Male Sprague-Dawley rats were subjected to decompensated HS followed by resuscitation. In addition to the time course of tissue injury and inducible NO synthase (iNOS) messenger RNA (mRNA) expression in the liver during HS, we investigated the effect of N6-(iminoethyl)-L-lysine(LNIL) (a specific inhibitor of iNOS) and also that of uric acid (a natural scavenger of peroxynitrite) on tissue injury and nitrotyrosine formation (a footprint of peroxynitrite) in the liver. RESULTS: The liver injury, evaluated by plasma aminotransferase levels and histology, became evident at the end of the shock period and had significantly increased 1 hour after the start of resuscitation (Shock-1 h). There was no iNOS mRNA expression in the liver at baseline, and it had clearly increased by Shock-1 h. Treatment with LNIL or uric acid significantly attenuated the tissue injury with a prominent reduction in nitrotyrosine formation in the liver. CONCLUSIONS: These lines of evidence suggest that one of the mechanisms by which NO production causes liver injury during HS may be its reaction with superoxide to form peroxynitrite.     

电场在电损伤中的作用机制

目的 研究高压电场在电损伤中的作用机制。方法 将36只新西兰大白兔，分为7组。除第1组12只白兔外，其余6组每组4只。使用已建立的非热电损伤模型，2～4组做肌纤维平行电场实验，5～7组做肌纤维垂直电场实验。各组分别在伤后0、2、24h行解剖探查及深烧伤指数(IDBI)分型；1组在伤后2h行^99mTc同位素扫描与1照相，伤后0、2h行组织学和超微结构等观察。结果 1组白兔局部皮肤无明显损伤，小极板深部组织坏死，大腿内侧持续肌肉痉挛；平行电场损伤重于垂直电场损伤；电流密度大、软组织量少、和电场轴线中心部位损伤相对较大；^99mTc检查灌注相和血池相明显改变，光镜下观察肌纤维水肿、坏死；电镜下胞膜双层脂质分子间水肿分离，但膜无微孔，核变短，核膜部分溶解、核内糖原颗粒增加，线粒体和内质网肿胀，肌丝溶解，肌丝间隙扩大及糖原颗粒减少。结论 构成高压电场的各因素导致选择性的电场内组织细胞、亚细胞和分子水平的非热损伤，并成为其进行性坏死的主要因素。     

大鼠烧伤后早期心肌组织核因子κB活化对细胞因子表达及心肌功能的影响

目的观察核因子(NF)κB活化在大鼠烧伤后早期心肌组织表达肿瘤坏死因子(TNF)α及心肌功能损害中的作用,进一步阐明烧伤后早期心肌功能损害的发生机制。方法将170只Wistar大鼠随机分为对照组(20只)、烧伤组(90只)、吡咯烷二硫代氨基甲酸盐(PDTC)组(60只)。后两组大鼠均于背部造成35％TBSAⅢ度烧伤后,立即腹腔注射等渗盐水,且PDTC组同时皮下注射PDTC 250 mg／kg。对照组除不烧伤外,其余处理同烧伤组。伤后3、6、12、24 h采用八导生理记录仪记录左心室收缩压(LVSP),左心室舒张末期压(LVEDP),室内压最大上升、下降速率( dp／dtmax、-dp／dtmax);逆转录聚合酶链反应和原位杂交法观察心肌组织TNF-αmRNA的表达。伤后1、3、6、12、24 h采用凝胶电泳迁移率变动分析法检测心肌组织NF-κB活性,以积分吸光度(A)值表示。对照组作相同检测。结果伤后3～24 h烧伤组大鼠LVSP、±dp／dtmax低于对照组(P<0．01),而LVEDP高于对照组(P<0．01)。伤后3 h烧伤组大鼠心肌组织TNF-αmRNA表达明显高于对照组, 6 h达峰值(P<0．01),它在心肌细胞中表达尤为明显。伤后1 h烧伤组大鼠心肌组织NF-κB活性迅速升高[积分A值为(20．3±3．4)×104],明显高于对照组积分A值(2．2±0．4)×104,3 h时达峰值,24 h时仍高于对照组(P<0．01)。与烧伤组比较,PDTC组上述指标有较明显的改善(P< 0．01)。结论大鼠严重烧伤后心肌组织NF-κB被活化,使其表达和释放促炎细胞因子,在心肌功能损害发生过程中起重要作用。     

Endothelin-1, inducible nitric oxide synthase and macrophage inflammatory protein-1alpha in the pathogenesis of stress ulcer in neurotraumatic patients

BACKGROUND: To prospectively identify histologically and endoscopically the effect of omeprazole on the expression of endothelin-1 (ET-1), inducible nitric oxide synthase (iNOS) and macrophage inflammatory protein-1alpha (MIP-1alpha) in the gastric mucosa of neurosurgical patients with stress ulcer. METHODS: Twenty-five patients with severe acute intracranial lesions caused by trauma were enrolled in this study. A 40 mg intravenous bolus of omeprazole (OME) was given daily for 7 days. The intragastric pH was continuously recorded for 24 hours on day 1 and 8. Endoscopic evaluation of the gastric corpus, antrum, and duodenal bulb was performed in the ICU, within 24 hours after brain injury, and at follow-up on the 7th day after admission. Paired biopsies were obtained for histologic examinations and immunohistochemical analysis was performed using a LSAB method for MIP-1alpha, ET-1, and iNOS. RESULTS: There were 72% and 70% of gastroduodenal mucosal lesions at the initial and follow-up endoscopies, respectively. However, the severity of mucosal lesions showed significant improvement in most patients at follow-up (p < 0.05). Mean percentages of time intragastric pH were greater than or equal to 4.0 were 20 +/- 11% and 70 +/- 17% on day 1 and 8, respectively (p < 0.05). The incidences of ET-1, iNOS and MIP-1alpha expression were not significantly different between the patients before and after OME prophylaxis. CONCLUSIONS: Prophylactic OME is effective in reducing the severity of stress ulcerations in severe neurotraumatic patients. High incidence of tissue ET-1 expression combined with increased activity of iNOS and MIP-1alpha may be responsible for the gastric mucosal injury. We also show that OME fails to counter the enhancement in the mucosal expression of ET-1, iNOS, and MIP-1alpha caused by severe brain damage.     

烫伤大鼠心肌细胞丝裂素活化蛋白激酶的活化及胞内分布规律的研究

目的　观察大鼠严重烫伤后早期心肌细胞中丝裂素活化蛋白激酶 [MAPKs,包括 p38激酶、细胞外信号调节激酶 (ERKs)和应激活化蛋白激酶 (JNK) ]的活化及胞内分布规律 ,探讨其与心肌损伤的关系。　方法　制作严重烫伤大鼠模型 ,于伤后 1、3、6、12、2 4h取其全血及心肌组织标本 ,并取正常大鼠的相应标本为对照。常规检测各血清标本中肌酸激酶同工酶 MB(CK MB)的活力 ;采用Western印迹法 ,检测各心肌组织标本中MAPKs各成员的活化情况 ,并对其组织切片行免疫组化染色。　结果　伤后 p38激酶、ERK均发生活化并伴核转位 ,以 1、3、6h最明显 (P <0 .0 1) ;伤后 1～ 2 4hJNK均未见活化。血清CK MB含量于伤后 3h升高 ,12h达高峰 (P <0 .0 5～ 0 .0 1)。　结论　p38激酶和ERK信号通路可能在严重烧伤后早期心肌细胞发生的损伤性反应中起重要作用 ,而前者可能是烧伤引发心肌损伤的主要信号转导通路之一。