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.

TLR4 mediates lung injury and inflammation in intestinal ischemia-reperfusion.

BACKGROUND: Splanchnic ischemia is common in critically ill patients, and it can result in injury not only of the intestine but also in distant organs, particularly in the lung. Local inflammatory changes play a pivotal role in the development of acute lung injury after intestinal ischemia, but the underlying molecular mechanisms are not fully understood. We sought to examine the role of Toll-like receptor 4 (TLR4) in the mouse model of intestinal ischemia-reperfusion (I/R)-induced lung injury and inflammation. MATERIALS AND METHODS: Adult male TLR4 mutant (C3H/HeJ) mice and TLR4 wild-type (WT) (C3H/HeOuJ) mice were subjected to 40 min of intestinal ischemia by clamping the superior mesenteric artery followed by 6 h of reperfusion. Lung histology was assessed and parameters of pulmonary microvascular permeability, inflammatory cytokine expression, and neutrophil infiltration were measured. Activation of mitogen-activated protein kinases (MAPKs) and the transcription factors nuclear factor κB (NF-κB) and activator protein-1 (AP-1) in the lungs were also detected. RESULTS: After intestinal I/R, lungs from TLR4 mutant mice demonstrated a significantly lower histological injury, a marked reduction of epithelial apoptosis associated with the decreased level of cleaved caspase-3 and the increased ratio of Bcl-xL to Bax proteins, and a large reduction in pulmonary vascular permeability and myeloperoxidase (MPO) activity in comparison with WT mice. TLR4 mutant mice also displayed marked decreases in tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-2 (MIP-2) expression. Following intestinal I/R, phosporylation of p38 MAPK and activation of NF-κB and AP-1 were significantly inhibited in lung tissue from TLR4 mutant mice compared with WT controls. CONCLUSIONS: These data suggest that TLR4 plays an important role in the pathogenesis of intestinal I/R-induced acute lung injury and inflammation and that p38 kinase and NF-κB may be involved in TLR4 signaling-mediated lung inflammatory processes during intestinal I/R.

Effects of early excision and grafting on cytokines and insulin resistance in burned rats.

UNLABELLED: Burn wound excision and grafting is a common clinical practice that decreases patient morbidity and mortality. It is not known, however, if the salutary effects of this procedure are related to effects on interleukin 6 (IL-6) and tumor necrosis factor (TNF-) α, and to reducing insulin resistance after burn. Sprague-Dawley rats were randomly divided into three groups: control, burn, burn ± excision groups. Rats in burn group were given a third-degree scald burn covering 30% total body surface area (TBSA) and no wound excision. Rats in burn ± excision group were subjected to a 30% third-degree burn followed by complete excision and allografting of the injury site within 15 min after burn. The rats in control group were treated in the same manner as the burn group, except that they were immersed in a room-temperature water. Glucose tolerance tests (GTT) were observed at 3 days after burn, euglycemic-hyperinsulinemic glucose clamps were performed at 4 days after burn and interleukin 6 (IL-6) and tumor necrosis factor (TNF-) α were determined after euglycemic-hyperinsulinemic glucose clamps. The levels of IL-6 and TNF-α increased after burn. Significant differences in GTT were observed between control and burn groups, and the rate of glucose infused measured in burned rats was significantly decreased compared with that in control at 4 days after burn. Early excision and grafting significantly decreased levels of IL-6 and TNF-α, and further reduced insulin resistance following thermal injury compared with burn group. CONCLUSION: Early excision and grafting appeared to have an effect on inflammatory mediators and further reduced insulin resistance induced by major burns.

[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.

[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.

[Interaction between p38 mitogen-activated protein kinase signal transduction pathway and NF-kappaB/IkappaB system on the proinflammatory cytokines release after burn trauma].

OBJECTIVE: To investigate the interaction between p38 mitogen-activated protein kinase signal transduction pathway and nuclear factor (NF)-kappaB/IkappaB system on the proinflammatory cytokines release after burn trauma. METHODS: Human monocyte line THP-1 were incubated with serum from eight healthy controls, burn sera, burn sera pretreatment with SB203580, and burn sera pretreatment with pyrrolidine dithiocarbamate (PDTC). After 24 hours incubation with serum, tumor necrosis factor (TNF)-alpha and interleukin-1beta (IL-1beta) levels in THP-1 culture supernatants were measured by ELISA. The activities of p38 MAPK and expressions of IkappaBalpha in THP-1 were measured by Western blot analysis. The EMSA method was used to characterize the binding activities of NF-kappaB and activating protein (AP)-1 in THP-1. RESULTS: In comparison with normal controls, burn sera resulted in a significant higher level release of TNF-alpha and IL-1beta in THP-1 [(7.30 +/- 0.84) ng/ml vs (2.20 +/- 0.28) ng/ml, P < 0.05; (2.88 +/- 0.38) ng/ml vs (0.81 +/- 0.14) ng/ml, P < 0.05], which were significantly inhibited by pretreatment with SB203580 or PDTC. Burn sera showed increased activities of p38 MAPK and AP-1 in THP-1 (4728 +/- 582 vs 1291 +/- 163, P < 0.05; 946 +/- 137 vs 361 +/- 40, P < 0.05), which were abolished by pretreatment with SB203580 but not PDTC. The expression of IkappaBalpha in THP-1 incubated with burn sera was significantly decreased than those incubated with control sera (1211 +/- 115 vs 2658 +/- 318, P < 0.05), which were abolished by pretreatment with PDTC but not SB203580. Burn sera also leaded to an increased activity of NF-kappaB in THP-1 (1636 +/- 170 vs 317 +/- 32, P < 0.05), which were abolished by pretreatment with PDTC but not SB203580. CONCLUSIONS: There are no direct interaction between p38 MAPK signal transduction pathway and NF-kappaB/IkappaB pathway. These two pathways, which regulate the production of TNF-alpha and IL-1beta in monocyte following burn trauma, are parallel and independent.

[Role of p38MAPK signal transduction pathway in Kupffer cells production of TNF-alpha and IL-1beta in severely burned rats].

OBJECTIVE: To investigate the role of p38 mitogen-activated protein kinase (MAPK) signal transduction pathway in the Kupffer cells production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in severely burns rats. METHODS: Male health adult Sprague-Dawley rats were randomized into four groups: sham burn rats given vehicle, sham burn rats given the p38 MAP kinase inhibitor SB203580, rats given a 30% total body surface area (TBSA) full-thickness burn and fluid resuscitation plus vehicle, and burn rats given injury and fluid resuscitation plus SB203580. Rats from each group were killed at 24 h after burn or sham burn and Kupffer cells (KCs) were isolated. After 18 h incubation, KCs next were stimulated with 50 ng/ml of LPS for 18 h. After stimulation, supernatants were removed for analysis of TNF-alpha and IL-1beta levels by ELISA. The TNF-alpha and IL-1beta mRNA expressions (by quantitative real-time RT-PCR) and the activities of p38 MAPK and JNK (by Western blot analysis) in KCs were examined. RESULTS: Eighteen hours after 50 ng/ml LPS stimulation, KCs from burn rats released significantly higher levels of TNF-alpha and IL-1beta than did shams. The mRNA levels of TNF-alpha and IL-1beta in KCs increased significantly postburn. Western blot analysis suggested that expression of phosphorylated p38 MAPK and JNK were increased in KCs harvested from burn group after stimulation with LPS compared with those from sham group. In vivo administration of SB203580 markedly suppressed both the release of TNF-alpha and IL-1beta and the mRNA expressions of TNF-alpha and IL-1beta in KCs from both sham and burn rats. p38 MAPK activity in KCs was abolished by administration with SB203580, whereas JNK was not. CONCLUSIONS: p38 MAPK signal transduction pathway mediates KCs production of proinflammatory cytokines TNF-alpha and IL-1beta in severely burned rats.

p38 mitogen-activated protein kinase inhibition attenuates burn-induced liver injury in rats.

This study was made to evaluate the effect of SB203580, a specific p38 MAP kinase inhibitor, on burn-induced hepatic injury as well as the activation of nuclear factor (NF)-kappaB in severely burned rats. Sprague-Dawley rats were divided into three groups: (1) sham group, rats underwent sham burn; (2) burn group, rats given third-degree burns over 30% total body surface area (TBSA) and treated with vehicle plus lactated Ringer solution for resuscitation 4 ml/(kg% TBSA); and (3) burn plus SB203580 group, rats given burn injury and fluid resuscitation plus SB203580 (10 mg/kg i.v., 15 min and 12 h after burn). Hepatocellular injury (measured by serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) and hepatocellular function (determined by the indocyanine green dye retention rate (ICG R15)) were assessed at 24 h post-burn. Liver histologic changes were also analyzed. Burn trauma resulted in increased serum aminotransferases concentrations, decreased ICG R15, elevated serum tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta levels and hepatic TNF-alpha and IL-1beta mRNA expressions, and worsen histologic condition. The level of Nuclear Factor (kappa) inhibitor (IkappaBalpha) in liver was decreased and DNA-binding activity of Nuclear Factor-kappaB (NF-kappaB) was increased after thermal injury. p38 MAP kinase was more significantly activated in liver harvested from burn rats than from shams. SB203580 inhibited the activation of p38 MAP kinase, reduced the levels of TNF-alpha and IL-1beta, and prevented burn-mediated liver injury. Both the IkappaBalpha level and NF-kappaB activity in the liver following burns was not affected by administration with SB203580. These findings suggest that (1) p38 MAP kinase activation is one important aspect of the signaling event that may mediate the release of TNF-alpha and IL-1beta and contributes to burn-induced liver injury and (2) p38 MAP kinase does not influence the activation of NF-kappaB directly in the liver of severely burned rats.

[The modulating role of p38 mitogen-activated protein kinase in the expression of tumor necrosis factor-alpha in hepatic cells and its role in hepatic injury in severely burned rats].

OBJECTIVE: To investigate The modulating role of p38 mitogen-activated protein kinase (MAPK) in the expression of tumor necrosis factor-alpha in hepatic cells and its role in hepatic injury in severely burned rats. METHODS: Twenty-four adult healthy male SD rats were randomly divided into three groups (8 rats in each group): sham group, burn group, and burn with SB203580 group. A rat model of full-thickness burn injury covering 30% total body surface area (TBSA) was reproduced. The specific inhibitor of p38MAPK (SB203580 in 10 mg/kg) was given to the rats in the burn with SB203580 group at 15 minutes and 12 hours after burn. The serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured at 24 postburn hours (PBHs). The TNF-alpha mRNA expression in the liver was determined by real-time reverse transcription polymerase chain reaction, and the expression levels of p38MAPK and phosphor-p38MAPK in the liver were determined by Western blot analysis. RESULTS: The serum levels of AST and ALT, and the expression of TNF-alpha mRNA in liver cells were significantly higher in burn group than those in sham and SB203580 groups (P < 0.05 or 0.01), but there was no difference between the two latter groups. It was indicated by Western blot results that there was no difference of p38MAPK expression in rat liver among the three groups (P > 0.05). The phospho-p38MAPK expression ratio among sham, burn and burn with SB203580 groups was 1.00:3.90:1.10. The phospho-p38MAPK expression was significantly lower in burn with SB203580 group than that in burn group (P < 0.01), but there was no significant difference compared with that in sham group (P > 0.05). CONCLUSION: The postburn activated p38MAPK in rat liver after severe burn injury enhances the expression of TNF-alpha mRNA and participates in the development of postburn hepatic injury.

[Role of p38 mitogen-activated protein kinase signal transduction pathway in the acute lung injury of severely burned rats].

OBJECTIVE: To investigate the role of p38 mitogen-activated protein kinase (MAPK) signal transduction pathway in the acute lung injury of severely burned rats. METHODS: Forty-eight adult healthy rats were randomly divided into three groups: sham group, burn control group, and burn + SB203580 group. A third-degree burns over 30% total body surface area rat model was used and pulmonary capillary permeability, lung water content, pulmonary histology and p38 MAPK activity were measured at 24 hours postburn. RESULTS: Burn trauma resulted in increased pulmonary capillary leakage permeability (42.5 +/- 4.7 vs. 12.1 +/- 1.4, P < 0.01), elevated lung water content (P < 0.05), and worsen histologic condition. There was a significant activation of p38 MAPK at 24 hours postburn compared with control. SB203580 inhibited the activation of p38 MAPK, reduced the pulmonary capillary leakage permeability (24.7 +/- 2.9 vs. 42.5 +/- 4.7, P < 0.01), decreased lung water content, and prevented burn-mediated lung injury. CONCLUSION: The activation of p38 MAPK is one important aspect of the signaling event that contributes to burn-induced lung injury.

Expression and regulation of vascular cell adhesion molecule-1 in human umbilical vein endothelial cells induced by sera from severely burned patients.

OBJECTIVE: The purpose of this study was to determine the expression and regulation of vascular cell adhesion molecule (VCAM)-1 in human umbilical vein endothelial cells (HUVECs) induced by sera from severely burned patients. DESIGN: Controlled laboratory study. SETTINGS: Research laboratory in a university hospital. SUBJECTS: HUVECs. INTERVENTIONS: HUVECs were incubated with serum from eight healthy controls and eight patients with thermal injuries of >50% total body surface area. The experiment was repeated after pretreatment with pyrrolidine dithiocarbamate, an inhibitory effect on nuclear factor-kappaB activation, SB203580, a specific p38 mitogen-activated protein kinase inhibitor, and PD98059, a mitogen-activated protein/extracellular signal-regulated kinase inhibitor. MEASUREMENTS AND MAIN RESULTS: Protein and messenger RNA expression of VCAM-1 was measured by flow cytometry and reverse transcription-polymerase chain reaction respectively. Soluble VCAM-1 level in HUVECs culture supernatants was measured by enzyme-linked immunosorbent assay. Sera from severely burned patients showed a stimulatory effect on VCAM-1 messenger RNA levels and an increased VCAM-1 expression on the endothelial cell surfaces. The soluble form of VCAM-1 molecules was also elevated by the stimulation of burn sera. In vitro peripheral blood mononuclear leukocytes adherence to HUVECs incubated with burn sera was significantly increased compared with those incubated with control sera. Finally, these events were significantly inhibited by pretreatment with antioxidants pyrrolidine dithiocarbamate or SB203580, whereas PD98059 had no significant effect. CONCLUSIONS: These findings suggest that sera from severely burned patients induced up-regulation of VCAM-1 expressions in HUVECs, and this process might be largely dependent on oxidant-mediated nuclear factor-kappaB activation and p38 mitogen-activated protein kinase pathways.

[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.

Role of p38 mitogen-activated protein kinase in Kupffer cell secretion of the proinflammatory cytokines after burn trauma.

This study was designed to investigate the role of p38 mitogen-activated protein (MAP) kinase on Kupffer cells (KCs) secretion of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta and hepatic injury following burn trauma. Sprague-Dawley rats were randomized into four groups: (1) sham burn rats given vehicle, (2) sham burn rats given the p38 MAP kinase inhibitor SB203580 (10mg/kg i.v., 15min and 12h after sham burn), (3) rats given a 30% total body surface area (TBSA) full-thickness burn and fluid resuscitation plus vehicle, and (4) burn rats given injury and fluid resuscitation plus SB203580. Rats from each group were killed at 24h post-burn to examine plasma aspartate transaminase (AST) and alanine transaminase (ALT) and KCs were isolated. The KCs secretion of TNF-alpha and IL-1beta and p38 MAP kinase activity (by Western blot analysis) were also examined. These studies showed by more significant activation of p38 MAP kinase in KCs harvested from burn rats than from shams. Burn trauma resulted in hepatic dysfunction and promoted KCs secretion of TNF-alpha and IL-1beta. SB203580 inhibited p38 MAP kinase activity, reduced KCs secretion of proinflammatory cytokines, and alleviated burn-mediated hepatic dysfunction. These data suggest p38 MAP kinase activation is one important aspect of the signaling event that may mediate the KCs secretion of proinflammatory cytokines TNF-alpha and IL-1beta following burn trauma.

Role of p38 mitogen-activated protein kinase in lung injury after burn trauma.

This study was undertaken to evaluate the effect of SB203580, a specific p38 mitogen-activated protein (MAP) kinase inhibitor, on burn-induced lung injury as well as the release of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in rats to characterize the role of p38 MAP kinase in lung injury after burn trauma. Sprague-Dawley rats were divided into three groups: 1) sham group, or rats who underwent sham burn; 2) control group, or rats given third-degree burns over 30% total body surface area (TBSA) and lactated Ringer solution for resuscitation; and 3) SB203580 group, or rats given burn injury and lactated Ringers solution with SB203580 inside for resuscitation. Pulmonary injury was assessed at 24 h by pulmonary capillary permeability determined with fluorescein isothiocyanate-labeled albumin and lung histologic analysis. TNF-alpha and IL-1beta protein in bronchoalveolar lavage fluid and serum were measured by enzyme-linked immunosorbent assay and p38 MAP kinase was activity determined in lung by Western blot analysis. These studies showed that significant activation of p38 MAP kinase at 24 h postburn compared with control. Burn trauma resulted in increased pulmonary capillary leakage permeability, elevated levels of TNF-alpha and IL-1beta in bronchoalveolar lavage fluid and serum, and worsened histologic condition. SB203580 inhibited the activation of p38 MAP kinase, reduced the levels of TNF-alpha and IL-1beta, and prevented burn-mediated lung injury. These data suggest that p38 MAP kinase activation is one important aspect of the signaling event that may mediate the release of TNF-alpha and IL-1beta and contributes to burn-induced lung injury.