Distinct cardiodynamic and molecular characteristics during early and late stages of sepsis-induced myocardial dysfunction

We hypothesized that progressive decline in myocardial performance would correlate with upregulation of markers for apoptotic mechanisms following increased duration of polymicrobial sepsis in the rat. Male Sprague-Dawley rats (350-400 g) were randomized into sham, 1-, 3- and 7-day sepsis groups. Each septic rat received 200 mg/kg cecal inoculum intraperitoneally (i.p). The post-mortem analysis showed a severely inflamed peritoneum with the presence of pus in all septic animals that was directly proportional to the duration of sepsis. We observed 10, 33 and 42% mortality in the 1-, 3- and 7-day sepsis groups, respectively. Septic animals at 3 and 7 days exhibited an increased wet lung/total body weight and heart weight/total body weight. A significant increase in total cardiac troponin I (cTnI) and C Reactive Protein (CRP) and endothelin-1 (ET-1) was also observed with an increased duration of sepsis. Myocardial ET-1 concentration in the 7-day post-sepsis group was significantly elevated compared to the sham and 1-day post-sepsis groups. Sepsis also produced a significant decrease in the mean arterial pressure in the 7-day post-sepsis group and tachycardia in the 1-, 3-, and 7-day post-sepsis groups compared to the sham group. A significant prolongation of the left ventricular isovolumic relaxation rate constant, tau, and left ventricular end-diastolic pressure in the 1-, 3- and 7-day post-sepsis groups compared to the sham group was observed. In addition, a significant decrease in the rates of left ventricular relaxation (-dP/dt) and contraction (+dP/dt) in the 3- and 7-day post-sepsis groups compared to the sham and 1-day post-sepsis group was observed. Sepsis produced a significant upregulation in the expression of myocardial TRADD, cytosolic active caspase-3, the Bax/Bcl(2) ratio, and the mitochondrial release of cytochrome C in the 3- and 7-day post-sepsis groups. We observed a progressive increase in the number of TUNEL positive nuclei, cytosolic caspase-3 activation and co-localization of PARP in the nuclei at 1, 3 and 7 days post-sepsis. These data suggest that the progression of sepsis from 1 day to 3-7 days produce distinct cardiodynamic characteristics with a more profound effect during later stages. The sepsis-induced decline in myocardial performance correlates with the induction of myocardial apoptosis.     

Ascorbate protects against impaired arteriolar constriction in sepsis by inhibiting inducible nitric oxide synthase expression

Compromised microvascular responsiveness is one of the key factors associated with mortality of septic patients. The present study addresses the mechanism of protection by ascorbate against impaired vasoconstriction in septic mice. Sepsis (i.e., cecal ligation and puncture (CLP) model) elevated both plasma protein carbonyl (i.e., an index of oxidative stress) and plasma nitrite/nitrate (NOx) levels, reduced baseline mean arterial blood pressure (MABP), and inhibited the MABP pressor response to angiotensin II (Ang II) at 6 h post-CLP. At the microvascular level, sepsis increased the inducible nitric oxide synthase (iNOS) mRNA level in cremaster muscle arterioles (18-25 microm diameter) at 3 h post-CLP, and impaired vasoconstriction to Ang II in these arterioles at 6 h post-CLP. At 24 h post-CLP, sepsis resulted in 9% survival. An intravenous bolus of ascorbate (200 mg/kg body wt) given 30 min prior to CLP prevented the protein carbonyl and NOx increases, partially restored the baseline arterial pressure, and completely protected against all arteriolar iNOS mRNA increases, arteriolar constriction hyporesponsiveness, and pressor response impairment. Survival increased to 65%. In septic mice, iNOS gene knockout resulted in protection of arteriolar constriction and pressor responses identical to that provided by ascorbate. Ascorbate bolus given 3 h post-CLP protected against the increase in plasma NOx concentration and against the pressor response impairment. We conclude that ascorbate may protect arteriolar vasoconstrictor responsiveness in sepsis by inhibiting excessive NO production.     

MAPK p38 antagonism as a novel method of inhibiting lymphoid immune suppression in polymicrobial sepsis

Although studies indicatethat a shift from a Th1 to a Th2 response contributes to a markedsuppression of cell-mediated immunity during sepsis, the mechanism bywhich this occurs remains unknown. Given that the mitogen-activatedprotein kinase (MAPK) p38 plays a critical role in the activation andfunction of immune cells, the aim of this study was to determine thecontribution of MAPK p38 activation to the immune dysfunction seen inpolymicrobial sepsis. To study this, polymicrobial sepsis was inducedin C3H/HeN male mice by cecal ligation and puncture (CLP). Spleniclymphocytes and purified T cells were harvested 24 h post-CLP,pretreated with the specific MAPK p38 inhibitor SB-203580, and thenstimulated with a monoclonal antibody against the T cell marker CD3.The results indicate that interleukin (IL)-2 release is markedlydepressed while the release of the immunosuppressive mediator, IL-10,as well as mRNA levels of IL-10 and IL-4, are augmented after CLP. Inhibition of MAPK p38 suppressed in vitro IL-10 levels as well asIL-10 and IL-4 gene expression while restoring the release of IL-2. Todetermine whether these in vitro findings could be translated to an invivo setting, mice were given 100 mg of SB-203580/kg body wt or salinevehicle (intraperitoneal) at 12 h post-CLP. Examination of ex vivolymphocyte responsiveness indicated that, as with the in vitro finding,septic mouse Th1 responsiveness was restored. In light of our recentfinding that delayed in vivo SB-203580 treatment also improved survivalafter CLP, we believe that these results not only illustrate the roleof MAPK p38 in the induction of immunosuppressive agents in sepsis butdemonstrate that SB-203580 administration after the initialproinflammatory state of sepsis significantly prevents the morbidityfrom sepsis.

     

Rapamycin Protects Sepsis-Induced Cognitive Impairment in Mouse Hippocampus by Enhancing Autophagy

The purpose of this study is to test the hypothesis that the mammalian target of rapamycin (mTOR) signaling pathway might mediate neuroprotection in a mouse model of septic encephalopathy and also to identify the role of autophagy. Mice were subjected to cecal ligation and puncture (CLP) or a sham operation, and all 50 mice were randomly assigned to five groups: sham, CLP+ saline, CLP+ rapamycin (1, 5, 10 mg/kg) groups. Two weeks after the operation, Morris water maze was conducted for behavioral test; Nissl staining was used for observing glia infiltration; immunohistochemical staining and biochemical measures in hippocampi were performed to detect mTOR targets and autophagy indicators. Immunochemistry revealed significant loss of neurons and increased glia infiltration in hippocampus after CLP operation. Inhibition of mTOR by rapamycin rescued cognitive deficits caused by sepsis (p < 0.05). Rapamycin did not affect total mTOR targets, while phosphorylated mTOR targets (p-mTOR-Ser2448, p-p70S6k-Thr389, p-AKT-S473) decreased (p < 0.05) and autophagy indicators (LC3-II, Atg5, Atg7) were increased, and P62 was decreased in rapamycin-treated CLP mice compared with the untreated (p < 0.05) in hippocampus. Rapamycin improves learning after sepsis through enhancing autophagy and may be a potentially effective therapeutic agent for the treatment of sepsis-induced cognitive impairment.     

富氢液对脓毒症小鼠心肌细胞线粒体自噬的影响

为评价富氢液（hydrogen-rich saline,HRS）对脓毒症小鼠心肌细胞线粒体自噬的调节及其对心功能障碍的治疗作用,选取72只雄性C57BL/6J小鼠作为研究对象,采用随机数字表法分为假手术组（Sham组）、假手术+富氢液组（Sham+HRS组）、脓毒症组（CLP组）、CLP+富氢液组（CLP+HRS组）,每组18只。采用盲肠结扎穿孔法建立小鼠CLP模型。Sham+HRS组和CLP+HRS组分别于造模后1、6 h时腹腔注射富氢液10 mL·kg^-1。每组随机取6只小鼠,于造模后24 h时收集小鼠颈动脉血样,采用ELISA法测定血液肿瘤坏死因子α（tumor necrosis factor-α,TNF-α）、白细胞介素（interleukin-1β,IL-1β）、肌钙蛋白I（cardiac troponin I,cTnI）和肌酸激酶同工酶（creatine kinase MB,CK-MB）水平;于造模后24 h时取心肌组织,采用荧光素-荧光酶发光法检测ATP,荧光分光光度法检测线粒体膜电位（mitochondrial membrane potential,MMP）。造模后24 h采用Western blot法测定心肌组织线粒体自噬相关蛋白微管关联蛋白轻链3Ⅱ/轻链3Ⅰ（microtubule-associated protein 1 light/protein 3 light,LC3Ⅱ/LC3Ⅰ）和蛋白62（protein 62,P62）的表达水平。结果显示,与Sham组比较,CLP组血清TNF-α、IL-1β、cTnI和CK-MB水平升高,心肌ATP、MMP水平下降,心肌LC3Ⅱ/LC3Ⅰ表达水平上调,P62表达水平下调,差异有统计学意义（P<0.05）;与CLP组比较,CLP+HRS组血清TNF-α、IL-1β、cTnI和CK-MB含量下降,心肌组织ATP、MMP水平升高,LC3Ⅱ/LC3Ⅰ表达水平进一步上调,P62表达进一步下调（P<0.05）。结果表明,富氢液对脓毒症小鼠心功能障碍的治疗作用可能是通过调节心肌细胞线粒体自噬实现的。研究旨在探讨富氢液对脓毒症小鼠心功能障碍的治疗作用及机制,以期为富氢液的临床转化提供理论依据。     

Glucan phosphate attenuates cardiac dysfunction and inhibits cardiac MIF expression and apoptosis in septic mice

Myocardial dysfunction is a major consequence of septic shock and contributes to the high mortality of sepsis. We have previously reported that glucan phosphate (GP) significantly increased survival in a murine model of cecal ligation and puncture (CLP)-induced sepsis. In the present study, we examined the effect of GP on cardiac dysfunction in CLP-induced septic mice. GP was administered to ICR/HSD mice 1 h before induction of CLP. Sham surgically operated mice served as control. Cardiac function was significantly decreased 6 h after CLP-induced sepsis compared with sham control. In contrast, GP administration prevented CLP-induced cardiac dysfunction. Macrophage migration inhibitory factor (MIF) has been implicated as a major factor in cardiomyocyte apoptosis and cardiac dysfunction during septic shock. CLP increased myocardial MIF expression by 88.3% (P < 0.05) and cardiomyocyte apoptosis by 7.8-fold (P < 0.05) compared with sham control. GP administration, however, prevented CLP-increased MIF expression and decreased cardiomyocyte apoptosis by 51.2% (P < 0.05) compared with untreated CLP mice. GP also prevented sepsis-caused decreases in phospho-Akt, phospho-GSK-3beta, and Bcl-2 levels in the myocardium of septic mice. These data suggest that GP treatment attenuates cardiovascular dysfunction in fulminating sepsis. GP administration also activates the phosphoinositide 3-kinase/Akt pathway, decreases myocardial MIF expression, and reduces cardiomyocyte apoptosis.     

Mechanical ventilation of isolated septic rat lungs: effects on surfactant and inflammatory cytokines.

The effects of mechanical ventilation (MV) on the surfactant system and cytokine secretion were studied in isolated septic rat lungs. At 23 h after sham surgery or induction of sepsis by cecal ligation and perforation (CLP), lungs were excised and randomized to one of three groups: 1) a nonventilated group, 2) a group subjected to 1 h of noninjurious MV (tidal volume = 10 ml/kg, positive end-expiratory pressure = 3 cmH(2)O), or 3) a group subjected to 1 h of injurious MV (tidal volume = 20 ml/kg, positive end-expiratory pressure = 0 cmH(2)O). Nonventilated sham and CLP lungs had similar compliance, normal lung morphology, surfactant, and cytokine concentrations. Injurious ventilation decreased compliance, altered surfactant, increased cytokines, and induced morphological changes compared with nonventilation in sham and CLP lungs. In these lungs, the surfactant system was similar in sham and CLP lungs; however, tumor necrosis factor-alpha and interleukin-6 levels were significantly higher in CLP lungs. We conclude that injurious ventilation altered surfactant independent of sepsis and that the CLP lungs were predisposed to the secretion of larger amounts of cytokines because of ventilation.     

Impact of repeated intravenous bone marrow mesenchymal stem cells infusion on myocardial collagen network remodeling in a rat model of doxorubicin-induced dilated cardiomyopathy

Bone marrow mesenchymal stem cells (MSCs) transplantation improved cardiac function and reduced myocardial fibrosis in both ischemic and non-ischemic cardiomyopathies. We evaluated the effects of repeated peripheral vein injection of MSCs on collagen network remodeling and myocardial TGF-β1, AT1, CYP11B2 (aldosterone synthase) gene expressions in a rat model of doxorubicin (DOX)-induced dilated cardiomyopathy (DCM). Thirty-eight out of 53 SD rats survived at 10 weeks post-DOX injection (2.5 mg/kg/week for 6 weeks, i.p.) were divided into DCM blank (without treatment, n = 12), DCM placebo (intravenous tail injection of 0.5 mL serum-free culture medium every other day for ten times, n = 13), and DCM plus MSCs group (intravenous tail injection of 5 × 10⁶ MSCs dissolved in 0.5 mL serum-free culture medium every other day for 10 times, n = 13). Ten untreated rats served as normal controls. At 20 weeks after DOX injection, echocardiography, myocardial collagen content, myocardial expressions of types I and III collagen, TGF-β1, AT1, and CYP11B2 were compared among groups. At 20 weeks post-DOX injection, 8 rats (67 %) survived in DCM blank group, 9 rats (69 %) survived in DCM placebo group while 13 rats (100 %) survived in DCM plus MSCs group. Left ventricular end-diastolic diameter was significantly higher and ejection fraction was significantly lower in DCM blank and DCM placebo groups compared to normal control rats, which were significantly improved in DCM plus MSCs group (all p < 0.05 vs. DCM blank and DCM placebo groups). Moreover, myocardial collagen volume fraction, types I and III collagen, myocardial mRNA expressions of TGF-β1, AT1, CYP11B2, and collagen I/III ratio were all significantly lower in DCM plus MSCs group compared to DCM blank and DCM placebo groups (all p < 0.05). Repeated intravenous MSCs transplantation could improve cardiac function by attenuating myocardial collagen network remodeling possibly through downregulating renin–angiotensin–aldosterone system in DOX-induced DCM rats.     

Therapeutic potential of plasma gelsolin administration in a rat model of sepsis

BackgroundGelsolin is an actin-binding protein found in the cytoplasm and in extracellular fluids including blood plasma. Plasma gelsolin concentration decreases after a wide range of injuries. We hypothesized that the repletion of gelsolin would limit inflammation and tissue injury in a rat model of sepsis using cecal ligation and double puncture (2CLP).MethodsHuman plasma gelsolin (pGSN, 10 mg in 1 ml saline) was administered once immediately following surgery, and control 2CLP (2CLP Alb) and sham animals were injected with 1 ml saline containing equimolar albumin. Treatments were administered intraperitoneally (IP), intravenously (IV), or subcutaneously (SC).ResultsGelsolin levels in the 2CLP Alb group were lower than in sham animals. Administration of pGSN increased levels when administered IV and SC, but not IP. Morbidity scores were significantly less severe in the 2CLP pGSN group than in the 2CLP Alb group when pGSN was administered IV and SC, but not IP. Furthermore, enzymatic activity indicative of tissue damage (lactate dehydrogenase and alanine transaminase) was significantly lower in 2CLP pGSN group when treated SC compared to 2CLP Alb group.ConclusionThese data provide further evidence that exogenous gelsolin can reduce morbidity from sepsis.     

Adipose-derived mesenchymal stem cells ameliorate the inflammatory reaction in CLP-induced septic acute lung injury rats via sTNFR1

We hypothesized that the adipose-derived mesenchymal stem cells (ADMSCs), which secrete high amounts of soluble molecules, such as soluble tumor necrosis factor receptor 1 (sTNFR1), may ameliorate sepsis-induced acute lung injury (ALI). A total of 120 male adult Sprague–Dawley rats were separated into four groups: the sham control (SC), sepsis induced by cecal ligation and puncture (CLP), CLP–ADMSCs, and CLP–sTNFR1 small interfering RNA (siRNA) groups; CLP groups underwent CLP and then received 1 × 10⁶ ADMSCs with or without knockdown of sTNFR1 intravenously at 1 hr after surgery. Rats were killed at 3, 6, 24, and 48 hr after the SC or CLP procedures. 5-Ethynyl-2′-deoxyuridine-labeled ADMSCs extensively colonized the lungs at 6, 24, and 72 hr after injection. The lung wet/dry (W/D) weight ratios in the CLP group were higher than those in SC group; however, ADMSCs ameliorated the W/D weight ratios following CLP, and this effect was abolished by sTNFR1 siRNA treatment. The levels of serum sTNFR1 and interleukin-10 (IL-10) were higher in the CLP–ADMSCs group and lower in the SC group than in other groups; interestingly, these levels were higher in CLP and CLP–sTNFR1 siRNA groups than in SC group. Tumor necrosis factor-α and IL-6 levels increased significantly after CLP, and ADMSCs could alleviate these changes, but the effect was weakened by sTNFR1 siRNA treatment. The lung cell apoptosis and edema levels were consistent with IL-6 levels among all groups. Therapeutically administered ADMSCs secrete sTNFR1, which most likely protects against ALI in septic rats by ameliorating inflammation and lung edema.     

脓毒症小鼠心肌损伤与中性粒细胞浸润的关系

目的:探讨脓毒症小鼠心肌损伤与中性粒细胞浸润的关系。方法:复制脓毒症动物模型,分对照组、假手术组、造模组,并设不同的时间点(2h、4h、8h、12h)。采用双抗夹心酶联免疫法(ELISA)检测血清肌钙蛋白(IcTnI),并测心肌组织髓过氧化物酶(MPO)活性。结果:正常组与假手术组各时间点血清cTnI、心肌组织MPO活性均无显著性差异。造模组心肌组织MPO活性较正常组和假手术组均有明显升高(P<0.05),且随着时间进展而增加;造模组血清cTnI浓度随着时间进展而增加,2小时与正常组及假手术组无显著性差异(P>0.05),4小时后显著高于正常组和假手术组(P<0.05);血清cTnI浓度与心肌组织MPO活性呈显著正相关(r=0.700,P=0.000)。结论:脓毒症心肌损伤时,心肌组织存在中性粒细胞浸润,中性粒细胞浸润程度与心肌损伤显著正相关。     

Transgenic Expression of FoxM1 Promotes Endothelial Repair following Lung Injury Induced by Polymicrobial Sepsis in Mice

Enhancing endothelial barrier integrity for the treatment of acute lung injury (ALI) is an emerging novel therapeutic strategy. Our previous studies have demonstrated the essential role of FoxM1 in mediating endothelial regeneration and barrier repair following lipopolysaccharide-induced lung injury. However, it remains unclear whether FoxM1 expression is sufficient to promote endothelial repair in experimental models of sepsis. Here, employing the FoxM1 transgenic (FoxM1 Tg) mice, we showed that transgenic expression of FoxM1 promoted rapid recovery of endothelial barrier function and survival in a clinically relevant model of sepsis induced by cecal ligation and puncture (CLP). We observed lung vascular permeability was rapidly recovered and returned to levels similar to baseline at 48 h post-CLP challenge in FoxM1 Tg mice whereas it remained markedly elevated in WT mice. Lung edema and inflammation were resolved only in FoxM1 Tg mice at 24 h post-CLP. 5-bromo-2-deoxyuridine incorporation assay revealed a drastic induction of endothelial proliferation in FoxM1 Tg lungs at 24h post-CLP, correlating with early induction of expression of FoxM1 target genes essential for cell cycle progression. Additionally, deletion of FoxM1 in endothelial cells, employing the mouse model with endothelial cell-restricted disruption of FoxM1 (FoxM1 CKO) resulted in impaired endothelial repair following CLP challenge. Together, these data suggest FoxM1 expression in endothelial cells is necessary and sufficient to mediate endothelial repair and thereby promote survival following sepsis challenge.     

Is gut the major source of proinflammatory cytokine release during polymicrobial sepsis?

Although studies have shown that the gut is capable of being a cytokine-producing organ and that the proinflammatory cytokines TNF-alpha, IL-1beta, and IL-6 are upregulated following the onset of sepsis, it remains unknown whether the gut is indeed the major source of the increased cytokine production under such conditions. To determine this, male rats were subjected to cecal ligation and puncture (CLP, a model of polymicrobial sepsis) or sham operation followed by the administration of normal saline solution subcutaneously (i.e., fluid resuscitation). Systemic and portal blood samples were taken simultaneously at 2, 5, 10, or 20 h after CLP or sham operation. Plasma levels of TNF-alpha, IL-1beta, and IL-6 were determined using an enzyme-linked immunosorbent assay. In additional animals, the small intestine was harvested at 10 h after CLP or sham operation and examined for TNF-alpha, IL-1beta, and IL-6 gene expression by RT-PCR. The results indicate that the levels of TNF-alpha, IL-1beta, and IL-6 in both systemic and portal blood samples were significantly elevated during sepsis with the exception that the increase in IL-1beta was not significant at 2 h after CLP. However, there were no significant differences in the levels of those proinflammatory cytokines between systemic and portal blood at any points after the onset of sepsis. Moreover, there were no significant alterations in the proinflammatory cytokine gene expression in the small intestine at 10 h after CLP. Since the levels of TNF-alpha, IL-1beta, and IL-6 were not significantly increased in portal blood as compared to systemic blood and since there was no upregulation of gene expression for these cytokines, it appears that organs other than the gut are responsible for the upregulated proinflammatory cytokines during polymicrobial sepsis.     

Adjuvant Potential of Selegiline in Attenuating Organ Dysfunction in Septic Rats with Peritonitis

Selegiline, an anti-Parkinson drug, has antioxidant and anti-apoptotic effects. To explore the effect of selegiline on sepsis, we used a clinically relevant animal model of polymicrobial sepsis. Cecal ligation and puncture (CLP) or sham operation was performed in male rats under anesthesia. Three hours after surgery, animals were randomized to receive intravenously selegiline (3 mg/kg) or an equivalent volume of saline. The administration of CLP rats with selegiline (i) increased arterial blood pressure and vascular responsiveness to norepinephrine, (ii) reduced plasma liver and kidney dysfunction, (iii) attenuated metabolic acidosis, (iv) decreased neutrophil infiltration in liver and lung, and (v) improved survival rate (from 44% to 65%), compared to those in the CLP alone rats. The CLP-induced increases of plasma interleukin-6, organ superoxide levels, and liver inducible nitric oxide synthase and caspase-3 expressions were ameliorated by selegiline treatment. In addition, the histological changes in liver and lung were significantly attenuated in the selegiline -treated CLP group compared to those in the CLP group. The improvement of organ dysfunction and survival through reducing inflammation, oxidative stress and apoptosis in peritonitis-induced sepsis by selegiline has potential as an adjuvant agent for critical ill.     

Early enhanced local neutrophil recruitment in peritonitis-induced sepsis improves bacterial clearance and survival

Neutrophils are critical for the rapid eradication of bacterial pathogens, but they also contribute to the development of multiple organ failure in sepsis. We hypothesized that increasing early recruitment of neutrophils to the focus of infection will increase bacterial clearance and improve survival. Sepsis was induced in mice, using cecal ligation and puncture (CLP); blood samples were collected at 6 and 24 h; and survival was followed for 28 d. In separate experiments, peritoneal bacteria and inflammatory cells were measured. Septic mice predicted to die based on IL-6 levels (Die-P) had higher concentrations of CXCL1 and CXCL2 in the peritoneum and plasma compared with those predicted to live (Live-P). At 6 h, Live-P and Die-P had equivalent numbers of peritoneal neutrophils and bacteria. In Die-P mice the number of peritoneal bacteria increased between 6 and 24 h post-CLP, whereas in Live-P it decreased. The i.p. injection of CXCL1 and CXCL2 in naive mice resulted in local neutrophil recruitment. When given immediately after CLP, CXC chemokines increased peritoneal neutrophil recruitment at 6 h after CLP. This early increase in neutrophils induced by exogenous chemokines resulted in significantly fewer peritoneal bacteria by 24 h [CFU (log) = 6.04 versus 4.99 for vehicle versus chemokine treatment; p < 0.05]. Chemokine treatment significantly improved survival at both 5 d (40 versus 72%) and 28 d (27 versus 52%; p < 0.02 vehicle versus chemokines). These data demonstrate that early, local treatment with CXC chemokines enhances neutrophil recruitment and clearance of bacteria as well as improves survival in the CLP model of sepsis.     

Effect of ascorbic acid on hepatic vasoregulatory gene expression during polymicrobial sepsis

The aim of this study was to investigate the effects of ascorbic acid on hepatic vasoregulatory gene expression during polymicrobial sepsis. Rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). Rats received either vehicle (n = 10) or ascorbic acid (AA, 100 mg/kg, n = 10) intravenously immediately after the CLP procedure. Serum aminotransferase levels and hepatic lipid peroxides markedly increased 24 h after CLP and this increase was attenuated by AA treatment. The hepatic concentrations of reduced glutathione decreased in CLP animals. This decrease was inhibited by AA. CLP significantly increased the mRNA level of ET-1 (p < 0.01) and ETB receptor (p < 0.01) in livers; an increase that was prevented by AA treatment. There were no significant changes in ETA mRNA expression among any of the experimental groups. There were significant increases in the mRNA expression of nitric oxide synthases (p < 0.01) and heme oxygenase-1 (p < 0.01) in livers from CLP animals. This increase was prevented by AA treatment. The expression of tumor necrosis factor-alpha and cyclooxygenase-2 mRNAs significantly increased 4.9-fold (p < 0.01) and 4.4-fold (p < 0.01) in livers from CLP animals, respectively. This increase was attenuated by AA treatment. Our data suggest that AA reduces oxidative stress and lipid peroxidation, regulates the hepatic vasoregulatory gene expression in polymicrobial sepsis and thus it could reduce hepatic microvascular dysfunction during sepsis.     

MiR-146b protect against sepsis induced mice myocardial injury through inhibition of Notch1

Myocardial dysfunction is a major cause of death in sepsis. MicroRNA-146b (miR-146b) has been reported to be related to myocardial disease. However, the role of miR-146b in sepsis as well as myocardial injury is still unclear. Septic cardiac dysfunction in mice was induced by cecal ligation and puncture (CLP) and miR-146b was found increased significantly in the myocardium tissue of CLP mice. It was found that up-regulation of miR-146b by agomiR injection suppressed expression of IL-1β in mice as well as myocardium apoptosis in CLP mice. However, suppression of miR-146b by antagomiR injection had inverse effects. Notch1 was identified as a target gene of miR-146b by bioinformatics analysis. And it was verified that in cardiomyocytes, the decrease of miR146b led to increase of both the mRNA and protein level of Notch1 and vice versa. In septic mice serum stimulated cardiomyocytes, up-regulation of miR-146b decreased the level of Notch1 and Hes1. The knockout of Notch1 in transgenic mice showed that the deficiency of Notch1 improved myocardial injury induced by CLP operation. The apoptosis of cardiomyocytes was relieved and the expression of IL-1β was decreased. In conclusion, miR-146b targets to Notch1 and protected cardiomyocytes against inflammation and apoptosis.