Macrophage migration inhibitory factor counter-regulates dexamethasone-induced annexin 1 expression and influences the release of eicosanoids in murine macrophages.

Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine and glucocorticoid (GC) counter-regulator, has emerged as an important modulator of inflammatory responses. However, the molecular mechanisms of MIF counter-regulation of GC still remain incomplete. In the present study, we investigated whether MIF mediated the counter-regulation of the anti-inflammatory effect of GC by affecting annexin 1 in RAW 264.7 macrophages. We found that stimulation of RAW 264.7 macrophages with lipopolysaccharide (LPS) resulted in down-regulation of annexin 1, while GC dexamethasone (Dex) or Dex plus LPS led to significant up-regulation of annexin 1 expression. RNA interference-mediated knockdown of intracellular MIF increased annexin 1 expression with or without incubation of Dex, whereas Dex-induced annexin 1 expression was counter-regulated by the exogenous application of recombinant MIF. Moreover, recombinant MIF counter-regulated, in a dose-dependent manner, inhibition of cytosolic phospholipase A2α (cPLA2α) activation and prostaglandin E2 (PGE2 ) and leukotriene B4 (LTB4 ) release by Dex in RAW 264.7 macrophages stimulated with LPS. Endogenous depletion of MIF enhanced the effects of Dex, reflected by further decease of cPLA2α expression and lower PGE2 and LTB4 release in RAW 264.7 macrophages. Based on these data, we suggest that MIF counter-regulates Dex-induced annexin 1 expression, further influencing the activation of cPLA2α and the release of eicosanoids. These findings will add new insights into the mechanisms of MIF counter-regulation of GC.

[Analgesic and sedative effects of inhaling a mixture of nitrous oxide and oxygen on burn patient during and after dressing change].

OBJECTIVE: To investigate the analgesic and sedative effects of inhaling a mixture of nitrous oxide and oxygen on burn patient during and after dressing change. METHODS: A total of 240 burn patients hospitalized in the Institute of Burn Research of Changhai Hospital Affiliated to the Second Military Medical University, Department of Burns of the First People's Hospital in Zhengzhou, and Department of Burns and Plastic Surgery of General Hospital of Ningxia Medical University from October 2011 to September 2012 were enrolled in our study, and they were all in accordance with the inclusion criteria. The 240 patients were divided into control group (n = 60, treated with inhalation of oxygen during dressing change) and treatment group (n = 180, treated with inhalation of a mixture of 65% nitrous oxide and oxygen during dressing change) according to the computer-generated list of random number. The other treatments in control group and treatment group were the same. Before, during, and after dressing change, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), oxygen saturation (SO2), and adverse effects were observed. The degree of pain and anxiety felt by the patients were respectively evaluated with the visual analogue scale (VAS) and Chinese version of the burn specific pain anxiety scale (C-BSPAS) at the same time points as above. Data were processed with analysis of covariance, chi-square test, analysis of variance, and rank sum test. RESULTS: There were no significant differences between control group and treatment group in the levels of HR, SBP, DBP, and SO2 before dressing change (with F values respectively 0.76, 0.06, 1.11, 0.70, P values all above 0.05). Compared with those of control group, the levels of HR, SBP, DBP, and SO2 in treatment group were significantly ameliorated during dressing change (with F values respectively 81.78, 146.36, 226.44, 205.62, P values all below 0.01). After dressing change, the levels of DBP in the two groups were close (F = 0.31, P > 0.05), but the levels of HR, SBP, and SO2 showed statistical differences (with F values respectively 7.02, 8.69, 12.23, P < 0.05 or P < 0.01). Before dressing change, the VAS scores were approximate between control group and treatment group (Z = 0.21, P > 0.05). Compared with those in control group (9.4 ± 0.7, 1.7 ± 2.5), the VAS scores were significantly lowered in treatment group during and after dressing change (1.6 ± 1.3, 0.7 ± 1.1, with Z values respectively 11.84, 3.35, P values all below 0.01). There was no significant difference in C-BSPAS score between control group and treatment group before dressing change (Z = 0.62, P > 0.05). Compared with those in control group (75 ± 13, 73 ± 12), the C-BSPAS scores in treatment group were decreased during and after dressing change (9 ± 15, 9 ± 14, with Z values respectively 11.91, 12.28, P values all below 0.01). There were no obvious adverse effects in two groups before, during, and after dressing change. CONCLUSIONS: A mixture of nitrous oxide and oxygen seems to have obvious analgesic and sedative effects on burn patients during dressing change, and it can be widely used.

[Lay emphasis on the treatment of massive burn casualties in conflagration].

Burn surgery belongs to disaster medicine. Burn is a common trauma that occurs in social activities of human beings in all ages, either in the time of peace or war. During the development of human medicine in modern times, the summary of experience in treating massive burn casualties due to severe fire accidents has effectively promoted the renovation of treating technology and theory of burns and the development of burn surgery. The results of treatment of burn injury in casualties occurred in the fire of Cocoanut Grove night club in Boston in 1942, and the high-rise apartment house fire in Shanghai in 2010 were summarized and analyzed in this article, emphasizing the correlating issues of inhalation injury.

Role of inhibition of p38 mitogen-activated protein kinase in liver dysfunction after hemorrhagic shock and resuscitation.

BACKGROUND: The liver is one of the organs most frequently affected by trauma and hemorrhagic shock; the exact role of p38 mitogen-activated protein kinase (MAPK) activation in response to hepatic hemorrhagic shock/resuscitation (HS/R) remains unclear. MATERIALS AND METHODS: C57Bl/6 mice were divided into four groups: sham-operated group, SB-only group, control group, and SB + HS/R group. Hepatocellular injury (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) and tumor necrosis factor (TNF-α) and interleukin (IL-1ß) messenger ribonucleic acid (mRNA) expression in the liver were assessed 6 h after resuscitation, p38 MAPK activation in the liver was assessed at 30 min after resuscitation. RESULTS: p38 MAPK activation was higher in the control group than other groups 30 min after resuscitation. p38 MAPK activation level in the SB + HS/R group did not change significantly compared with that of sham and SB-only groups, but was significantly lower than that in the control group. The TNF-α mRNA expression in the control group was significantly higher than that in the sham group. The TNF-α mRNA levels after HS/R in the SB + HS/R group were significantly lower than those in the control group and were roughly the same as those in the sham and SB-only groups. IL-1ß mRNA expression showed similar changes in the four groups. Serum ALT and AST levels in the control group were significantly higher than those in the sham group. The increase in serum ALT and AST levels after HS/R in the SB + HS/R group was significantly less pronounced than that in the control group and markedly higher than that in the sham group. CONCLUSIONS: p38 MAPK was phosphorylated during the HS/R process. Inhibiting the activation of p38 MAPK may attenuate HS/R injury to the liver.

Increased hsp70 of glucocorticoid receptor complex induced by scald and heat stress and its possible effect on the affinity of glucocorticoid receptor.

BACKGROUND: Glucocorticoid (GC) insensitivity/GC resistance is an important etiological and prognostic factor in multiple diseases and pathophysiological processes such as scald, shock and asthma. The function of GC was mediated by glucocorticoid receptor (GR). Scald not only decreased the expression of GR but also reduced the affinity of GR, which played an important role in GC resistance in scalded rats. Whereas the molecular mechanism responsible for the decrease of GR affinity resulted from scald remains unclear. Recent studies showed that the changes of heat shock proteins (hsp) especially hsp90 and hsp70 of GR heterocomplex were associated with GR low affinity in vitro. METHODS: The affinity of GR in hepatic cytosols and in the cytosols of SMMC-7721 cells were determined by radioligand binding assay and scatchard plot. GR heterocomplex in cytosols were captured by coimmunoprecipation and the levels of hsp90 and hsp70 of GR complex were detected by quantitative Western blotting. RESULTS: Similar with that of hepatic cytosol of scalded rats, a remarkable decrease of GR affinity was also found in the cytosol of heat stressed SMMC-7721 cells. The level of hsp70 of GR complex in hepatic cytosol of scalded rats (30% total body surface area immersion scald) and in cytosol of heat stressed human hepatocarcinoma cell line SMMC-7721 were both increased by 1.5 fold, whereas no change of hsp90 in GR heterocomplex was found. According to the correlation analysis, there may be a positive relationship between increased hsp70 of GR complex and decreased GR affinity in the cytosols. CONCLUSIONS: The primary results indicated that the level of hsp70 of GR heterocomplex was increased in the hepatic cytosol of scalded rats and the cytosol of heat stressed SMMC-7721 cells. The increase of hsp70 of GR complex might be associated with the decrease of GR affinity.

Notoginsenoside R1 attenuates renal ischemia-reperfusion injury in rats.

Ischemia-reperfusion (I/R) injury of the kidney is a complex pathophysiological process and a major cause of acute renal failure. It has been shown that I/R injury is related to inflammatory responses and activation of apoptotic pathways. Inhibition of certain elements of inflammatory responses and apoptotic pathway seemed to ameliorate renal I/R injury. As an effective element of Panax notoginseng, NR1 has antioxidant, anti-inflammatory, antiapoptotic, and immune-stimulatory activities. Therefore, we speculate that NR1 can attenuate renal I/R injury. Ischemia-reperfusion injury was induced by renal pedicle ligation followed by reperfusion along with a contralateral nephrectomy. Male Sprague-Dawley rats were randomized to four groups: sham group, I/R control group, NR1-1 group (rats treated with NR1, 20 mg.kg.d) and NR1-2 group (rats treated with NR1, 40 mg.kg.d). All animals were killed 72 h after I/R induction. Blood and renal tissues were collected. Renal dysfunction was observed by the level of serum creatinine and histological evaluation. Apoptosis and inflammatory response in the tissue of kidney were detected mainly with molecular biological methods. NR1 attenuated I/R-induced renal dysfunction as indicated by the level of serum creatinine and histological evaluation. It prevented the I/R-induced increases in the levels of proinflammatory cytokine TNF-alpha, myeloperoxidase activity, phosphorylation of p38, and activation of nuclear factor kappaB with cell apoptosis in the kidney and enhanced expression of antiapoptosis cytokine bcl-2. Treatment with NR1 improves renal function after I/R associated with a significant reduction in cell apoptosis and inflammatory responses, which may be related to p38 and nuclear factor kappaB inhibition.

[Repair of deep burn and traumatic wounds in lower extremities with combined transplantation of multiple pedicled skin flaps].

OBJECTIVE: To summarize the clinical experience in repair of deep burn and traumatic wounds with combined transplantation of different types of pedicled skin flaps in lower extremities. METHODS: Two hundred and thirty-six patients with 271 deep wounds in lower extremities after burn or trauma were repaired with muscular skin flaps, local fascial flaps and island flaps with vascular pedicle (more than 20 types) in our department from Jan. 1998 to Sept. 2008. RESULTS: Complete necrosis of skin flaps occurred in 1 case, congestion and necrosis over the edge of skin flaps occurred in 3 cases, which were healed after grafting, and other skin flaps survived well with soft texture. Skin flaps were too bulky in 26 cases, among them 17 cases were thinned, and the appearance of other skin flaps were satisfactory. In 68 patients with functional region injury were recovered to certain extent without contracture. CONCLUSIONS: Skin flaps with pedicles, multiple transplantations if necessary, can repair deep wounds satisfactorily in lower extremities after deep burn or trauma injury.

Activation of p38 MAPK by reactive oxygen species is essential in a rat model of stress-induced gastric mucosal injury.

Stress ulceration is a common complication in critically ill patients and can result in significant upper gastrointestinal bleeding associated with a high morbidity and mortality. At present, little is known of the molecular mechanisms underlying the incidence of this type of gastric damage. In the present study, we investigated the temporal activation of the redox-sensitive p38 signaling transduction cascade and its roles in a well-defined experimental model of cold immobilization stress-induced gastric ulceration. Exposure of Sprague-Dawley rats to 6 h of cold immobilization stress led to a rapid activation of p38 in the gastric mucosa at as early as 15 min after stress, and this activation was maximal after 1.5 h of stress and still persisted until the end of stress. Selectively blocking p38 by pretreatment with SB 239063, a potent and selective p38 inhibitor, suppressed the stress-promoted TNF-alpha, IL-1beta, and CINC-1 production and then prevented the subsequent neutrophil infiltration, gastric mucosal epithelial necrosis and apoptosis, and the ulcerative lesions formation. Prior administration of the free radical scavengers, tempol and N-acetyl-L-cysteine, abolished the stress induction of p38 activation and the resulting mucosal inflammation and gastric injury. These results demonstrate that reactive oxygen species-mediated p38 activation plays an essential role in the pathogenesis of stress-induced gastric inflammatory damage in the rat model of cold immobilization stress. Our findings suggested that inhibition of p38 activation might be a potential strategy for the prophylaxis and treatment of stress ulceration.

[Role of c-Jun NH (2)-terminal kinase in insulin resistance after burn].

OBJECTIVE: To investigate the role of c-Jun NH (2)-terminal kinase (JNk) in insulin resistance after burn and its mechanism. METHODS: Twenty-four Sprague-Dawley rats were randomized to control, burn and burn + anisomycin groups. The rats in control group received sham burn trauma, and burn and burn + anisomycin groups received 30% total body surface area (TBSA) full thickness burn injury. Anisomycin (5 mg/kg) together with 250 microl dimethyl sulfoxide (DMSO) was injected to the rats in anisomycin group intravenously, and only 250 microl DMSO in the other two groups. Euglycemic-hyperinsulinemic glucose clamps was performed 2 hours after the injection. The changes of phospho-serine 307, phospho-tyrosine of insulin receptor substrate (IRS)-1 and phospho-JNK in muscle tissues were determined and compared using immunoprecipitation and Western blot analysis or immunohistochemistry in the three groups. RESULTS: The infusing rates of total 10% glucose (mg x kg(-1) x min(-1)) in control, burn and burn + anisomycin group were 12.3 +/- 0.4, 6.6 +/- 0.3, 6.5 +/- 0.4, respectively. The level of IRS-1 Serine 307 phosphorylation and phospho-JNK in muscle increased significantly, while insulin-induced tyrosine phosphorylation of IRS-1 decreased markedly after burn. CONCLUSIONS: The activation of JNK elevates the level of IRS-1 phospho-serine 307 and might play a role in insulin resistance after burn in rats.

Sustained activation of nuclear factor-kappaB by reactive oxygen species is involved in the pathogenesis of stress-induced gastric damage in rats.

OBJECTIVE: Stress ulceration is a common complication in critically ill patients, but the mechanisms involved are poorly understood. In this study we investigated the temporal activation of the redox-sensitive transcription factor nuclear factor-kappaB and its roles in an experimental model of cold immobilization stress-induced gastric mucosal lesions. DESIGN: Prospective, controlled, and randomized animal study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: The rats were subjected to cold immobilization stress for a total of 6 hrs. The temporal profiles of nuclear factor-kappaB activation and expression of tumor necrosis factor-alpha, interleukin-1beta, cytokine-induced neutrophil chemoattractant-1 (CINC-1), intercellular adhesion molecule-1 (ICAM-1), and inducible nitric oxide synthase (iNOS) were determined in the gastric corpus mucosa of stressed rats. To study the roles of nuclear factor-kappaB activation, rats received an intravenous bolus of a specific nuclear factor-kappaB inhibitor Bay 11-7082 (20 mg/kg) 1 hr before stress. For antioxidant administration, rats were treated with intravenous injection of a free radical scavenger pyrrolidine dithiocarbamate (50, 100, and 200 mg/kg) 1 hr before stress. MEASUREMENTS AND MAIN RESULTS: Exposure of rats to 6 hrs of stress led to a rapid and persistent activation of nuclear factor-kappaB, which was associated with transient degradation of inhibitory protein IkappaBalpha and slower but sustained degradation of IkappaBbeta. Nuclear factor-kappaB activation preceded the induction of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs, all of which were linearly increased with the duration of stress. Bay 11-7082 selectively blocked the stress-induced nuclear factor-kappaB activation and up-regulation of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs. Inhibition of expression of these proinflammatory genes prevented the increases in myeloperoxidase activity (an indicator of neutrophil infiltration) in gastric mucosa and the development of gastric damage. Pyrrolidine dithiocarbamate dose-dependently inhibited the stress-induced nuclear factor-kappaB pathway activation and consequential proinflammatory gene expression, neutrophil infiltration, and gastric damage, suggesting the involvement of reactive oxygen species in these processes. CONCLUSIONS: Sustained activation of nuclear factor-kappaB by reactive oxygen species is an important in vivo mechanism mediating stress-induced gastric inflammatory damage in rats.

[Mechanism of p38 mitogen-activated protein kinase in postburn acute pulmonary injury in scalded rats].

OBJECTIVE: To investigate the role of p38 mitogen-activated protein kinase (MAPK) signal transduction pathway in the production of the proinflammatory factors such as tumor necrosis factor (TNF-alpha) and interleukin 1beta (IL-1beta) in lungs and in the pulmonary endothelial cell injury in severely scalded rats. METHODS: Forty eight adult healthy SD rats were randomly divided into three groups with 16 rats in each group, i.e. sham, burn and burn with SB203580 treatment groups. The changes in the TNF-alpha and IL-1beta contents in serum and bronchoalveolar lavage fluid (BALF), the von Willebrand factor (vWF) contents in plasma and pulmonary microvessels and pulmonary activating protein (AP-1) activity were determined at 24 postburn hours (PBH). RESULTS: Compared with those in sham group, the TNF-alpha and IL-1beta contents in serum and BALF and the vWF content in plasma (194.2% +/- 28.3% vs 93.2% +/- 14.3%) at 24 PBH in burn group increased significantly (P < 0.01), whereas vWF content in pulmonary microvessel decreased obviously (1.1 +/- 0.3 vs 3.3 +/- 0.4, P < 0.01). In addition, the pulmonary AP-1 activity also increased at 24 PBH. Nevertheless, all the above indices improved obviously in burn with SB203580 (inhibitor of p38 MAPK signal transduction pathway) treatment group when compared with those in burn group. CONCLUSION: AP-1 might mediate the production of proinflammatory factors, such as TNF-alpha and IL-1beta in lungs leading to pulmonary vascular endothelial injury, after being activated by activated p38 MAPK.

[Clinical observation of the long-term effects of rhEGF on deep partial-thickness burn wounds].

OBJECTIVE: To evaluate the safety and long-term effect of recombinant human epithelial growth factor (rhEGF) on deep partial-thickness burn wounds. METHODS: Thirty-seven burn patients were enrolled in this study and were observed by randomized, double-blinded and placebo-controlled protocol. An area of deep partial-thickness burn wounds from each patient was divided into control (C) and treatment (T) portions. The wound in C was treated with normal saline while that in T with rhEGF. The patients were followed-up for 1 and 4 years after wound healing. The healed wounds were evaluated by modified Vancouver scar scale in terms of scar index (SI). RESULTS: 1 year after wound healing, it was found that the SI in T group (7.19 +/- 1.67) was obviously lower than that in C group (8.92 +/- 1.78, P < 0.01). The SI in T group (6.12 +/- 1.54) was still evidently lower than that in C group (8.09 +/- 1.81, P < 0.01) four years after wound healing. There were no signs of development of tumor or cancer in all the tested burn wound areas. CONCLUSION: External application of rhEGF might be beneficial to the healing quality of deep partial-thickness burn wound with less scar formation and better long-term effects, and it is safe.

[Inhibition of nimodipine on production of proinflammatory by Kupffer cells in severe burned rats].

OBJECTIVE: To study whether nimodipine, a dihydropyridine-type calcium channel blocker, can inhibit the production of interleukin-1beta(IL-1beta), interleukin-6(IL-6) by Kupffer cells(KC) and down-regulate its level of plasma after severe burn injury. METHODS: KC of normal rats were isolated with portal vein catheter, intrahepatic digestion and density gradient centrifugation. Intracellular calcium concentration ([Ca2+]i) in individual KC after stimulated with postburn serum was assessed fluorometrically with microspectrofluorimeter. Level of IL-1beta and IL-6 in the supernatant of KC cultured with postburn serum were detected by enzyme-linked immunosorbent assay(ELISA). SD rats underwent 30% total body surface area(TBSA) full thickness burn 6 hours later, KCs was isolated and their mRNA were extracted. Level of IL-1beta mRNA and IL-6 mRNA were detected by ribonuclease protection assay(RPA). Levels of plasma IL-1beta and IL-6 were also detected. Role of nimodipine on above-mentioned effects were observed. RESULTS: Compared with that of control group, levels of [Ca2+]i of KCs and IL-1beta and IL-6 supernatant in burn group increased significantly(all P<0.01). At present of 1 micromol/L nimodipine, however, the [Ca2+]i, IL-1beta, IL-6 values decreased significantly(all P<0.01). The level of plasma cytokines and KC mRNA in burn group also increased significantly. After intravenously injection with nimodipine (40 microg x kg(-1) x h(-1)), the numerical values decreased significantly(all P<0.01). CONCLUSION: Kupffer cells of rats are activated to secret IL-1beta and IL-6 after severe burn injury and this process is realized through calcium ion signal transduction channel. Nimodipine can inhibit IL-1beta and IL-6 production of KC by preventing its mRNA transcription, down-regulating its level of plasma.