Oral glutamine enhances heat shock protein expression and improves survival following hyperthermia

No pharmacologic agent has shown benefit in treating heatstroke. Previous data indicate that enhanced heat shock protein 70 (HSP-70) expression can improve survival postexperimental heatstroke. Glutamine (GLN) can enhance HSP-70 expression in other injury models. This study assessed if orally administered GLN could enhance tissue HSP expression and could improve survival following whole body hyperthermia. Intestinal permeability and plasma endotoxin were assayed to determine if enhanced HSP expression correlated with improved organ function. GLN (0.65 g/kg) or an iso-nitrogenous control (Travasol; T) was given to rats via gavage twice daily for 5 days pre-heatstroke. Hyperthermia was performed in anesthetized rats by heating animals to 42 degrees C (rectal temperature) for 30 min. HSP-70 analyzed via Western blot. Gut permeability was measured 6 and 24 h post-hyperthermia. Plasma endotoxin was measured 24 h post-hyperthermia. Survival was analyzed for 5 days post-hyperthermia. GLN administration enhanced gut and lung HSP-70 post-hyperthermia. GLN administration led to significantly enhanced gut heat shock factor 1 (HSF-1) activation before heatstroke and at 1 h postheat stress. GLN decreased gut permeability at 6 and 24 h post-hyperthermia versus T. Plasma endotoxin also decreased in GLN-treated rats 24 h post-hyperthermia. Oral GLN therapy significantly improved survival (P < 0.05). Our results indicate that oral GLN can enhance tissue HSP-70 and HSF-1 activation post-hyperthermia. These results also indicate that enhanced HSP-70 may have functional significance as GLN-treated animals had decreased gut permeability, plasma endotoxin, and improve survival following lethal hyperthermia. Enhanced expression of HSP-70 may be an important mechanism leading to enhanced survival via GLN. These data indicate that oral GLN may useful in prevention of mortality from heatstroke in at risk populations.     

Hypertonic saline-dextran improves intestinal perfusion and survival in porcine endotoxin shock

OBJECTIVE: To examine the effects of hypertonic (7.5%) saline-6% dextran 70 (HSD) and isotonic (0.9%) saline-6% dextran 70 (ISD) on cardiovascular function and intestinal perfusion in experimental endotoxin shock. DESIGN: Experimental, randomized, unblinded, interventional study. SETTING: University experimental animal laboratory. SUBJECTS: Anesthetized and mechanically ventilated landrace pigs (n = 24). INTERVENTIONS: Induction of endotoxin (ET) shock by infusion of Escherichia coil lipopolysaccharide endotoxin (serotype 0111: B4) followed by no fluid treatment (control; C) or small-volume (4 mL/kg) treatment with HSD or ISD. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure, central venous pressure, pulmonary artery pressure, pulmonary artery occlusion pressure, cardiac output, portal vein blood flow, intestinal microcirculation, intramucosal (regional) P(CO2), intestinal-arterial gap of CO2, and intramucosal pH were monitored, and blood gases were analyzed. Infusion of ET resulted in hypokinetic shock, which in untreated animals led to cardiovascular deterioration and a survival rate of only 33% at 300 mins after start of ET infusion. ISD treatment transiently improved hemodynamic variables and mucosal blood flow but did not affect the survival rate vs. C. Significant beneficial, long-lasting effects of HSD infusion on hemodynamics, especially on mucosal blood flow and intramucosal pH, were demonstrable, resulting in a survival rate of 86%. The relative risk of death at 300 mins was 1.20 for ISD vs. C and 0.17 for HSD vs. C. CONCLUSION: Small-volume HSD resuscitation is much more effective than ISD resuscitation. Variables that were improved include cardiac output, portal blood flow, and intestinal mucosal blood flow in ET shock, all of which improve survival. Such beneficial effects of HSD on splanchnic perfusion may be of value in treating critically ill septic patients in the intensive care unit.     

Geranylgeranylacetone attenuates septic diaphragm dysfunction by induction of heat shock protein 70

OBJECTIVE: The purposes of the present study were to evaluate the induction of heat shock protein (HSP) 70 expression in the diaphragm by geranylgeranylacetone (GGA) administration and to determine the effect of HSP70 induction on diaphragm contractility measured in vitro and the production of oxygen-derived free radicals during experimental septic peritonitis. DESIGN: Prospective laboratory study. SETTING: University laboratory. SUBJECTS: One-hundred sixty male Wistar rats. INTERVENTIONS: In experiment 1, rats received GGA intragastrically, and time-dependent induction of HSP70 expression in the diaphragm was determined at 0, 12, 24, and 36 hrs after GGA administration. To evaluate dose-dependent inhibition of GGA-induced HSP70 expression by quercetin, rats were pretreated with progressive doses of quercetin before GGA administration. In experiment 2, rats received gum arabic solution (vehicle), 100, 200, or 400 mg/kg of GGA. In experiment 3, rats were pretreated with quercetin or glycerol before GGA or vehicle administration. Intra-abdominal sepsis was induced by cecal ligation and perforation (CLP) under inhalation anesthesia after GGA or vehicle administration in experiments 2 and 3. MEASUREMENTS AND MAIN RESULTS: Western blot analysis using diaphragm homogenates obtained from normal rats showed that HSP70 expression peaked at 24 or 36 hrs after GGA administration and that pretreatment with >10 mg/kg of quercetin blocked the induction of HSP70 expression by GGA. CLP induced diaphragmatic dysfunction and increased diaphragmatic malondialdehyde concentrations and superoxide dismutase and glutathione peroxidase activities. GGA attenuated CLP-induced diaphragm dysfunction and increased malondialdehyde concentrations in a dose-dependent manner but did not affect superoxide dismutase and glutathione peroxidase activities after CLP. Diaphragm dysfunction and increased diaphragmatic malondialdehyde concentrations after CLP were maintained on quercetin pretreatment despite GGA administration. CONCLUSIONS: GGA induces HSP70 expression in the diaphragm, and this induction attenuates septic diaphragm impairment by inhibiting the production of oxygen-derived free radicals.     

Glucosamine administration improves survival rate after severe hemorrhagic shock combined with trauma in rats

We have previously shown that glucosamine administration resulted in higher cardiac output and improved tissue perfusion after trauma-hemorrhage with resuscitation in rats, which was associated with the increased levels of protein O-linked-N-acetylglucosamine (O-GlcNAc). The purpose of the study was to evaluate the effect of glucosamine on the survival, without resuscitation, in rats. Adult male rats underwent midline laparotomy and 55% of total blood volume was withdrawn for 25 min under isoflurane anesthesia. At the end of the hemorrhage period, 2.5 mL of 150 mM glucosamine or equivalent osmolarity of mannitol solution was injected intravenously for 10 min. The survival time, mean blood pressure, heart rate, and central body temperature were monitored continuously; then, the O-GlcNAc levels in heart, brain, liver, and muscle were measured by means of Western blot analysis. Glucosamine administration significantly increased the survival rate in comparison with mannitol administration (percentage of survival after 2 h, 47% vs. 20%; P < 0.05). The mean arterial pressure was significantly higher in the glucosamine group for 18 min after treatment. The protein O-GlcNAc levels, assessed 30 min after glucosamine treatment, were significantly increased in the heart, brain, and liver. These data demonstrate that i.v. glucosamine administration improves the survival rate after trauma-hemorrhage without resuscitation; this effect may be related to the glucosamine-induced increase in protein O-glycosylation. Furthermore, the increase in mean arterial pressure may suggest a vasoactive and/or positive inotropic effect of glucosamine in hypovolemic shock.     

脑缺血再灌注损伤模型大鼠参附注射液干预后热休克蛋白70的表达

背景：参附注射液可通过改善微循环,增加组织血氧含量发挥对缺血再灌注损伤的保护作用。目的：观察参附注射液对大鼠脑缺血再灌注损伤后热休克蛋白70表达的影响。方法：将SD大鼠随机分为3组：假手术组、大脑中动脉闭塞缺血再灌注损伤模型组、参附注射液组。结果与结论：应用参附注射液1d后,改善了缺血再灌注大鼠脑部神经细胞的排列,减轻了胞体肿胀,核固缩等现象,应用3d后改善更为明显,胞体结构已较清晰,核固缩、溶解程度显著减轻,胞体肿胀现象明显改善。参附注射液组治疗后1,3d热休克蛋白70表达明显高于假手术组与模型组。提示参附注射液对脑缺血再灌注具有显著的保护作用,其作用可能是通过促进热休克蛋白70的表达来实现的。     

脑缺血再灌注损伤模型大鼠参附注射液干预后热休克蛋白70的表达

背景:参附注射液可通过改善微循环,增加组织血氧含量发挥对缺血再灌注损伤的保护作用。目的:观察参附注射液对大鼠脑缺血再灌注损伤后热休克蛋白70表达的影响。方法:将SD大鼠随机分为3组:假手术组、大脑中动脉闭塞缺血再灌注损伤模型组、参附注射液组。结果与结论:应用参附注射液1d后,改善了缺血再灌注大鼠脑部神经细胞的排列,减轻了胞体肿胀,核固缩等现象,应用3d后改善更为明显,胞体结构已较清晰,核固缩、溶解程度显著减轻,胞体肿胀现象明显改善。参附注射液组治疗后1,3d热休克蛋白70表达明显高于假手术组与模型组。提示参附注射液对脑缺血再灌注具有显著的保护作用,其作用可能是通过促进热休克蛋白70的表达来实现的。     

Androstenetriol improves survival in a rodent model of traumatic shock

Trauma results in activation of the hypothalamic-pituitary-adrenal axis to mediate a cascade of neurohormonal changes as a defensive mechanism. Its prolongation, however, leads to a hypermetabolic, hypoperfused, and immunosuppressed state, setting the stage for subsequent sepsis and organ failure. Androstenetriol (5-androstene-3beta, 7beta, 17betatriol - AET), a metabolite of dehydroepiandrosterone, up-regulates the host immune response markedly, prevents immune suppression and controls inflammation, leading to improved survival after lethal infections by several diverse pathogens and lethal radiation. Such actions may be useful in improving survival from traumatic shock. HYPOTHESIS: The neurosteroid AET will increase survival following traumatic shock. METHODS: A combat relevant model of traumatic shock was used. Male Sprague-Dawley rats were anesthetized, catheterized and subjected to soft tissue injury (laparotomy). Animals were allowed to regain consciousness over the next 0.5 h and then bled 40% of their blood volume over 15 min. Forty-five minutes after the onset of hemorrhage animals were randomized to receive either a single subcutaneous dose of AET (40 mg/kg, sc) or vehicle (methylcellulose). Volume resuscitation consisted of l-lactated Ringer's (three times the shed blood volume), followed by packed red blood cells (one-third shed red cell volume). Animals were observed for three days. RESULTS: A total of 24 animals were studied. Of the 12 animals randomized to receive AET, all (100%) survived compared to 9 of 12 animals (75%) randomized to receive the vehicle (p < 0.05). CONCLUSION: AET significantly improved survival when administered subcutaneously in a single dose in this rodent model of traumatic shock. Further survival and mechanism studies are warranted.     

地塞米松对创伤休克大鼠肝脏热休克蛋白70表达的影响

目的 探讨地塞米松对创伤休克肝组织中热休克蛋白70(HSP70)的表达变化以及对肝脏结构和功能的影响.方法 雄性健康Wistar大鼠72只,采用双侧股骨骨折伴失血性休克创伤模型,随机分成止常对照组12只,创伤休克组30只,创伤休克地塞米松组30只,地塞米松采用腹腔注射给药.动态观察伤后0.5、2、4、6、8 h大鼠肝组织HSP70、肝脏病理、肝功能、TNF-α、IL-6等变化.HSP70采用免疫印迹法测定其蛋白含量,并进行计算机图像分析.结果 HSP70伤后2h较正常对照相比差异有统计学意义,伤后6 h达到高峰,伤后8 h仍持续在较高水平.TNF-α、IL-6伤后逐渐升高,并于伤后6 h达到高峰,和正常组相比,差异有统计学意义.光镜下伤后4 h肝窦内淤血明显,有大量炎性细胞浸润;血清ALT、TB伤后4 h开始增高,8 h达到峰值.腹腔注射地塞米松后,HSP70在伤后各个时相点的表达均较创伤休克组明显增强,峰值仍然在伤后6 h.TNF-α、IL-6伤后各个时相点均迅速回落.肝脏大体淤血、肿胀明显减轻;光镜下伤后4 h肝细胞变性明显好转,肝窦内见淤血减轻,仅见少许淋巴细胞及中性粒细胞浸润;血清ALT、TB明显下降.结论 地塞米松可增强HSP70在创伤失血性休克后肝组织中的表达,可减轻创伤失血性休克后肝脏的继发性损害,表明地塞米松对创伤休克后肝脏的保护作用与HSP70密切相关.     

Levosimendan attenuates multiple organ injury and improves survival in peritonitis-induced septic shock: studies in a rat model

Introduction

The aim of this study was to investigate the effects of levosimendan on rodent septic shock induced by cecal ligation and puncture (CLP).

Methods

Three hours after peritonitis-induced sepsis, male Wistar rats were randomly assigned to receive an intravenous infusion of levosimendan (1.2 μg/kg/min for 10 min and then 0.3 μg/kg/min for 6 h) or an equivalent volume of saline and vehicle (5% dextrose) solution.

Results

The levosimendan-treated CLP animals had significantly higher arterial pressure and lower biochemical indices of liver and kidney dysfunction compared to the CLP animals (P < 0.05). Plasma interleukin-1β, nitric oxide and organ superoxide levels in the levosimendan-treated CLP group were less than those in CLP rats treated with vehicle (P < 0.05). In addition, the inducible nitric oxide synthase (iNOS) in lung and caspase-3 expressions in spleen were significantly lower in the levosimendan-treated CLP group (P < 0.05). The administration of CLP rats with levosimendan was associated with significantly higher survival (61.9% vs. 40% at 18 h after CLP, P < 0.05). At postmortem examination, the histological changes and neutrophil filtration index in liver and lung were significantly attenuated in the levosimendan-treated CLP group (vs. CLP group, P < 0.05).

Conclusions

In this clinically relevant model of septic shock induced by fecal peritonitis, the administration of levosimendan had beneficial effects on haemodynamic variables, liver and kidney dysfunction, and metabolic acidosis. (1) Lower levels of interleukin-1β, nitric oxide and superoxide, (2) attenuation of iNOS and caspase-3 expressions, and (3) decreases of neutrophil infiltration by levosimendan in peritonitis-induced sepsis animals suggest that anti-inflammation and anti-apoptosis effects of levosimendan contribute to prolonged survival.     

Diferuloylmethane inhibits neutrophil infiltration and improves survival of mice in high-dose endotoxin shock

Gram-negative septic shock is a systemic inflammatory response of the body caused primarily by the cell wall component (lipopolysaccharide) of the gram-negative bacteria. During high-dose endotoxin shock, neutrophils infiltrate and accumulate in the liver, causing hepatocellular injury. Cell adhesion molecules, specifically intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), play an important role in the infiltration of neutrophils in the liver tissue. In this study, we demonstrate that diferuloylmethane exerts protective effect in high-dose endotoxin shock by improving survival and reducing the severity of endotoxin shock symptoms such as lethargy, diarrhea, and watery eyes following a challenge with lipopolysaccharide. We demonstrate here that diferuloylmethane inhibits the transmigration and infiltration of neutrophils from blood vessels to the underlying liver tissue and, hence, inhibits the damage to the tissue. Diferuloylmethane blocks the induced expression of ICAM-1 and VCAM-1 in liver and lungs. Diferuloylmethane, being a natural compound, may have few side effects and may be useful in attenuating multiple organ injury in pathological conditions arising due to excessive infiltration of neutrophils into the tissues.     

Glutamine attenuates lung injury and improves survival after sepsis: role of enhanced heat shock protein expression

OBJECTIVE: Heat shock protein (HSP) expression is vital to cellular and tissue protection after stress or injury. However, application of this powerful tool in human disease has been limited, as known enhancers of HSPs are toxic and not clinically relevant. Glutamine (GLN) can enhance HSP expression in non-clinically relevant animal injury models. The aim of this study was to assess the ability of GLN to enhance pulmonary HSP expression, attenuate lung injury, and improve survival after sepsis in the rat. DESIGN: Prospective, randomized, controlled animal trial. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: We utilized a rat model of cecal ligation and puncture to induce sepsis. GLN or saline was administered 1 hr after initiation of sepsis via single tail-vein injection. We analyzed heat shock factor-1 phosphorylation, HSP-70, and HSP-25 via Western blot. Tissue metabolism was assayed by magnetic resonance spectroscopy. Occurrence of lung injury was determined via histopathologic examination. An inhibitor of HSP expression, quercetin, was utilized to assess role of HSP expression in prevention of sepsis-related mortality. MEASUREMENTS AND MAIN RESULTS: GLN, given after initiation of sepsis, enhanced pulmonary heat shock factor-1 phosphorylation, HSP-70, HSP-25, and attenuated lung injury after sepsis. Further, GLN improved indices of lung tissue metabolic function (adenosine 5-triphosphate/adenosine 5-diphosphate ratio, nicotinamide adenine dinucleotide) after sepsis. No significant effect of GLN on lung tissue-reduced glutathione was observed. GLN treatment led to a significant decrease in mortality (33% [6 of 18] GLN-treated rats vs. 78% [14 of 17] saline-treated rats). Administration of the HSP inhibitor quercetin blocked GLN-mediated enhancement of HSP expression and abrogated GLN's survival benefit. CONCLUSIONS: GLN has been safely administered to critically ill patients and shown to improve outcome without clear understanding of the protective mechanism. Our results indicate GLN may prevent the occurrence of lung injury, lung tissue metabolic dysfunction, and mortality after sepsis via enhancement of deficient lung heat shock factor-1 phosphorylation/activation and HSP expression.     

Beneficial effects of dextran 70 versus Ringer's acetate on pulmonary function, hemodynamics and survival in a porcine endotoxin shock model

The effects of Dextran 70 with NaCl as against Ringer's acetate on hemodynamics, gas exchange, oxygen transport and survival were evaluated in a porcine model of pulmonary and circulatory insufficiency induced by a continuous i.v. endotoxin infusion over 6 h. Dextran and Ringer's acetate were infused continuously to maintain baseline mean left atrial pressure (MLAP) throughout the endotoxin period. Twelve pigs receiving endotoxin + Ringer's acetate displayed a progressive 45% decline in cardiac output (Qt) and a two peaked increase in pulmonary vascular resistance (PVR) with a late increase of 250%. Venous admixture (Qva/Qt) increased progressively more than 6-fold and extravascular lung water (EVLW) increased by 55%. Mean arterial blood pressure (MAP) fell by 25%, oxygen delivery by 40%, base excess (BE) ranged between - 4.5 and - 9 mmol.1(-1) at the end of the endotoxin period and 4 of 12 animals died. Polymorphonuclear cell count (PMNs) fell rapidly by 90% and was severely decreased throughout the endotoxin period. Contrastingly, the 12 pigs that received endotoxin + Dextran maintained Qt near baseline and PVR was significantly lower in this group. Qva/Qt increased progressively more than 4-fold, but was significantly lower than in the Ringer's group as was the increase in EVLW (23%). MAP only decreased by 10%, oxygen delivery only decreased by 20%. BE ranged between - 1.0 and - 3.0 at the end of the endotoxin period and all animals survived. PMNs fell by 90% at 0.5 h but subsequently tended to return towards baseline. PMNs were significantly increased compared with the Ringer's group. The amount of Ringer's acetate necessary to maintain a stable MLAP averaged 4.6 times the Dextran volume. The superiority of Dextran as compared with Ringer's acetate in this endotoxemic shock model seems to be consequent to better rheological effects combined with pharmacological interactions with granulocytes.     

Mesenteric lymph duct ligation improves survival in a lethal shock model

The goal of this study was to test the hypothesis that factors released from the gut and carried in the mesenteric lymph contribute to mortality in a lethal gut I/R model. To test this hypothesis, a lethal splanchnic artery occlusion (SAO) shock model was used in male Sprague-Dawley rats. In the first set of experiments, ligation of the mesenteric lymph duct (LDL), which prevents gut-derived factors carried in the intestinal lymphatics from reaching the systemic circulation, significantly improved 24-h survival after a 20-min SAO insult (0% vs. 60% survival; P < 0.05). This increase in survival in the LDL-treated rats was associated with a blunted hypotensive response. Because increased iNOS-induced NO levels have been implicated in SAO-induced shock, we measured plasma nitrite/nitrate levels and liver iNOS protein levels in a second group of animals. Ligation of the mesenteric lymph duct significantly abrogated the SAO-induced increase in plasma nitrite/nitrate levels and the induction of hepatic iNOS (P < 0.05). In an additional series of studies, we documented that LDL increased not only 24-h but also long-term 7-day survival. During the course of these studies, we made the unexpected finding that Sprague-Dawley rats from different animal vendors had differential resistance to SAO, and that the time of the year that the experiments were carried out also influenced the results. Nonetheless, in conclusion, these studies support the hypothesis that factors carried in the mesenteric lymph significantly contribute to the development of irreversible shock after SAO.     

Hypertonic saline solution increases the expression of heat shock protein 70 and improves lung inflammation early after reperfusion in a rodent model of controlled hemorrhage

Hypertonic saline solution (HS solution, NaCl 7.5%) has shown to restore hemodynamic parameters in hemorrhagic shock and to decrease the inflammation triggered by ischemia-reperfusion injury (I-R). Therefore, our objective was to investigate the effects of HS solution on the mechanisms involved in I-R, in an experimental model of controlled hemorrhagic shock. Wistar rats (280-350 g) were submitted to controlled bleeding, keeping the mean arterial pressure around 40 mmHg, for 1 h. After that, rats were randomized and treated with HS solution (4 mL/kg) or normal saline (34 mL/kg). There were no differences in hemodynamic parameters between both groups for at least 2 h after shock. No difference either was observed in reactive oxygen species generation (measured indirectly by malondialdehyde concentration) or cytokines (interleukins 6 and 10) production (measured by enzyme-linked immunosorbent assay). Quantitative analysis of lung tissue showed a smaller neutrophil infiltration in animals that received HS solution. Moreover, the animals in the HS group showed an increased expression of heat shock protein 70. Therefore, we concluded that treatment of hemorrhagic shock with HS solution can decrease pulmonary inflammation and increase cellular protection by up-regulating heat shock protein 70 expression.     

Serum levels of heat shock protein 70 in patients with preeclampsia: a pilot-study

OBJECTIVE: To evaluate the serum levels of heat shock protein (Hsp) 70 in patients with severe preeclampsia (PE) in comparison to controls. The pathophysiology of PE can be explained, in part, by alterations of endothelial function caused by endothelial cell activation and injury. HSP 70 is essential for cellular recovery, survival and maintenance of homeostasis. STUDY DESIGN: In a matched pair study, serum levels of Hsp 70 were measured in 55 patients with late (group A, n = 24) and early (group B, n = 31) onset of severe PE, and in 55 normotensive controls (group C, n = 24 and group D, n = 31) matched for gestational age. Early onset of severe PE was defined as onset of disease at less than 34 weeks of gestation (34 + 0). Serum levels were determined using a sandwich enzyme-linked immunosorbent assay. RESULTS: The overall median serum levels of Hsp 70 were 2.82 ng/mL (SD +/- 8.33) in preeclamptic women, and 1.01 (SD +/- 1.38) ng/mL in controls (P = 0.08). The median serum levels of Hsp 70 were 0.52 ng/mL (SD +/- 1.14) in group A and 0.86 (SD +/- 1.29) ng/mL in group C (P = 0.15). The median serum levels of Hsp 70 were 4.94 ng/mL (SD +/- 10.46) in group B and 1.33 (SD +/- 2.28) ng/mL (P = 0.04) in group D. The difference between group A and B was also statistically significant (P = 0.01). CONCLUSION: Our study revealed higher serum levels of Hsp 70 in patients with early onset of severe PE. Further studies are recommended in order to elucidate the possible role of Hsp 70 in the pathophysiology of PE.     

热休克蛋白70对大鼠体外心脏细胞功能的影响

目的观察重酒石酸去甲肾上腺素诱导后热休克蛋白70在体外心脏中的表达,并探讨热休克蛋白70对大鼠体外心脏细胞功能的影响.方法实验于2003-03/09在华中科技大学同济医学院药理实验室进行.取成年雄性Wistar大鼠12只,随机分为2组,每组6只[1]生理盐水组腹腔注射生理盐水0.4 mL,注射后24 h取体外心脏,常规建立Langendorff体外心脏灌注模型,灌注15 min转为工作心15 min后停灌45 min,恢复灌注15 min改为工作心30 min.[2]重酒石酸去甲肾上腺素组腹腔注射重酒石酸去甲肾上腺素3.1μmol/kg(0.53 mg/kg),24 h后取体外心脏,方法同生理盐水组.采用Western blot法测定心肌细胞中热休克蛋白70含量及生化指标.结果12只大鼠全部进入结果分析.[1]热休克蛋白70含量(吸光度)重酒石酸去甲肾上腺素组明显高于生理盐水组(t=10.16,P＜0.01).[2]生化指标重酒石酸去甲肾上腺素组三磷酸腺苷含量、超氧化物歧化酶活性、心肌线粒体Ca2+-ATPase活性、心肌线粒体合成三磷酸腺苷能力优于生理盐水组[(13.67±2.60),(5.36±0.89)μmol/g;(2.44±0.14),(4.64±0.29)μkat/g;(6.77±0.90),(2.54±0.28)μkat/g;(124.22±13.58),(61.25±5.84)mmol/g;尸均＜0.01],丙二醛含量、肌酸激酶和乳酸脱氢酶漏出率、心肌细胞内Ca2+含量、心肌线粒体Ca2+含量低于生理盐水组(P＜0.01).结论重酒石酸去甲肾上腺素诱导的热休克蛋白70的高表达对缺血再灌注未成熟心肌细胞功能具有明显的保护效应,可以减轻细胞内和线粒体内Ca2+超载而发挥其细胞保护效应,减轻再灌注损伤.     

热休克蛋白70对大鼠体外心脏细胞功能的影响

目的：观察重酒石酸去甲肾上腺素诱导后热休克蛋白70在体外心脏中的表达,并探讨热休克蛋白70对大鼠体外心脏细胞功能的影响.方法：实验于2003-03/09在华中科技大学同济医学院药理实验室进行.取成年雄性Wistar大鼠12只,随机分为2组,每组6只：[1]生理盐水组：腹腔注射生理盐水0.4 mL,注射后24 h取体外心脏,常规建立Langendorff体外心脏灌注模型,灌注15 min转为工作心15 min后停灌45 min,恢复灌注15 min改为工作心30 min.[2]重酒石酸去甲肾上腺素组：腹腔注射重酒石酸去甲肾上腺素3.1μmol/kg（0.53 mg/kg）,24 h后取体外心脏,方法同生理盐水组.采用Western blot法测定心肌细胞中热休克蛋白70含量及生化指标.结果：12只大鼠全部进入结果分析.[1]热休克蛋白70含量（吸光度）：重酒石酸去甲肾上腺素组明显高于生理盐水组（t=10.16,P＜0.01）.[2]生化指标：重酒石酸去甲肾上腺素组三磷酸腺苷含量、超氧化物歧化酶活性、心肌线粒体Ca^2＋-ATPase活性、心肌线粒体合成三磷酸腺苷能力优于生理盐水组[（13.67&;#177;2.60）,（5.36&;#177;0.89）μmol/g;（2.44&;#177;0.14）,（4.64&;#177;0.29）μkat/g;（6.77&;#177;0.90）,（2.54&;#177;0.28）μkat/g;（124.22&;#177;13.58）,（61.25&;#177;5.84）mmol/g;P均＜0.01],丙二醛含量、肌酸激酶和乳酸脱氢酶漏出率、心肌细胞内Ca^2＋含量、心肌线粒体Ca^2＋含量低于生理盐水组（P＜0.01）.结论：重酒石酸去甲肾上腺素诱导的热休克蛋白70的高表达对缺血再灌注未成熟心肌细胞功能具有明显的保护效应,可以减轻细胞内和线粒体内Ca^2＋超载而发挥其细胞保护效应,减轻再灌注损伤.     

大鼠角膜碱烧伤后热休克蛋白70的表达(英文)

背景:角膜碱烧伤后损伤修复受许多因素的影响,热休克蛋白可促进变性、损伤蛋白质的迅速恢复或清除。目的:观察大鼠角膜碱烧伤后热休克蛋白70的表达及其与角膜损伤修复的关系。方法:检查大鼠眼无炎症及其他病变后,奥布卡因滴眼液点眼2次,棉签吸除结膜囊液体,将统一规格直径5mm的滤纸片浸泡于1mol/L NaOH溶液中10s,然后置于大鼠角膜中央30s制作大鼠角膜碱烧伤模型。分别于碱烧伤后6h,1,3,7,14,21d取材。结果与结论:RT-PCR、免疫组织化学染色、Western blot结果均显示热休克蛋白70mRNA和蛋白在角膜碱烧伤后1d即开始升高,7d时达高峰,14d后开始下降。苏木精-伊红染色及电镜观察显示角膜损伤在烧伤后6h即较明显,烧伤后7d逐渐恢复。提示大鼠角膜碱烧伤后热休克蛋白70的表达与碱烧伤后角膜损伤修复过程一致,参与了大鼠角膜碱烧伤后细胞的自我保护及修复过程。     

Adrenomedullin reduces vascular hyperpermeability and improves survival in rat septic shock

Objective Current therapies of sepsis and septic shock require administration of a large volume of fluid to maintain hemodynamic stability. The vasoregulatory peptide adrenomedullin has been shown to prevent the transition to the fatal hypocirculatory septic state by poorly understood mechanisms. We tested the hypothesis that therapeutic administration of adrenomedullin would reduce vascular hyperpermeability, thereby contributing to improved hemodynamics and survival. Design Prospective randomized controlled animal study. Subjects Male Sprague–Dawley rats (270 g). Interventions We used 4.8 × 10³ U/kg of Staphylococcus aureus α-toxin, a pore-forming exotoxin, to induce vascular leakage and circulatory shock in rats. The infusion rate was 24 μg/kg per hour. Adrenomedullin was started 1 h after α-toxin administration. Measurement and results Infusion of α-toxin in rats induced cardiocirculatory failure resulting in a 6-h mortality of 53%. α-Toxin provoked massive vascular hyperpermeability, which was indicated by an enrichment of Evans blue dye albumin in the tissues of lung, liver, ileum and kidney. Plasma fluid loss led to a significant hemoconcentration. Hemodynamic impairment observed after α-toxin infusion was closely correlated to vascular hyperpermeability. Therapeutic administration of 24 μg/kg per hour adrenomedullin reduced 6-h mortality from 53% to 7%. Stabilization of the endothelial barrier by adrenomedullin was indicated by reduced extravasation of albumin and plasma fluid and may have contributed to hemodynamic improvement. Conclusions These data suggest that adrenomedullin-related reduction of vascular hyperpermeability might represent a novel and important mechanism contributing to the beneficial effects of this endogenous vasoregulatory peptide in sepsis and septic shock. Electronic supplementary material The online version of this article () contains supplementary material, which is available to authorized users. Bettina Temmesfeld-Wollbrück and Bernhard Brell contributed equally to this study