Interaction between p38 mitogen-activated protein kinase signal transduction pathway and NF-kappaB/IkappaB system on the proinflammatory cytokines release after burn trauma / 中华外科杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

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 / 中华烧伤杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSION</b>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.</p>

Activation of p38 MAPK signal transduction pathway by burn serum and the expression of VCAM-1 in HUVECs induced by NF-kappaB / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the influence of burn serum on the expression of vascular cell adhesion molecule-1 (VCAM-1) of human umbilical vein endothelial cells (HUVECs) andits signal transduction mechanism.</p><p><b>METHODS</b>HUVECs cultured in vitro were employed for the experiment, and were divided into normal control (NC, with addition of normal serum), burn serum (BS, with addition of burn serum), SB203580 (with addition of 10 micromol/L SB203580 treatment 1 hour before burn serum treatment) and PDTC [with 10 mmol/L pyrrolidine dithiocarbamate (PDTC) 1 hour before burn serum treatment] groups. Protein and mRNA expression of VCAM-1 in HUVECs was measured by flow cytometry and reverse transcription polymerase chain reaction (RT-PCR) respectively at 0, 6, 12, 24 and 36 hours after burn serum treatment. The expression of VCAM-1 on HUVEC surface and the soluble VCAM-1 (sVCAM-1) content in HUVECs culture supernatants were measured by ELISA at 24 hours after the serum stimulation. Adherence of peripheral blood mononuclear leukocytes (PBMC) adherence to HUVECs was also observed in vitro.</p><p><b>RESULTS</b>The expression of VCAM-1 mRNA increased obviously in BS group after the burn serum stimulation and reached peak level at 24 post stimulation hour (PSH), and it decreased thereafter. The above expression was significantly decreased in SB203580 and PDTC groups at 24 PSH, but there was no difference compared with normal control (P > 0.05). The VCAM-1 expression on the membrane of HUVEC was evidently higher in BS group (66.5 +/- 6.2) than that in NC group (19.1 +/- 1.9, P < 0.05) at 24 PSH, but it was decreased significantly in SB203580 (21.7 +/- 2.3) and PDTC (23.1 +/- 2.4) groups and there was no significant difference compared with NC group (P > 0.05), and which was evidently lower than that in BS group (P < 0.05). The VCAM-1 content in the supernatant of BS group (125 +/- 10 ng/L) was obviously higher than that in NC (23 +/- 3 ng/L), SB203580 (27 +/- 5 ng/L) and PDTC (29 +/- 5 ng/L) groups. (P < 0.05). The number of PBMCs adherent to HUVECs in BS group [(197 +/- 11)%] was much larger than that in NC group [(100 +/- 4)%], SB203580 group [(113 +/- 7)%] or PDTC group [(97 +/- 112)%] at 24 PSH (P < 0.05), but no difference between NC group and SB203580, PDTC groups (P > 0.05).</p><p><b>CONCLUSION</b>Burn serum can enhance the expression of VCAM-1 in HUVECs through p38 MAPK signaling pathway, and the activation of NF-kappaB was also involved in this process.</p>