Mechanism of altered TNF-alpha expression by macrophage and the modulatory effect of Panax notoginseng saponins in scald mice.
OBJECTIVE
To explore the mechanism of altered tumor necrosis factor-alpha (TNF-alpha) expression by peritoneal macrophages (PMPhi) and Panax notoginseng saponins (PNS) modulation in light of NF-kappaB signal transduction in severely scalded mice.


METHODS
Eighteen percent total body surface area (TBSA) full-thickness scalded mice were used. PMPhi was collected at different time intervals (0, 2, 6, 12, 24 and 48 post-burn hour (PBH)) separately. The following parameters were measured: TNF-alpha mRNA and IL-10 mRNA expression (reverse transcription-polymerase chain reaction, RT-PCR), protein kinase C (PKC) activity (isotope incorporation analysis), NF-kappaB activity (electrophoretic mobility shift assay, EMSA), IkappaB-alpha expression (Western blot).


RESULTS
After scald, increased expression of TNF-alpha mRNA of PMPhi peaked at 12 PBH. Meanwhile, expression of IL-10 mRNA dropped to the lowest level at 12 PBH. NF-kappaB activity was markedly activated and reached its peak at 2 PBH. Membrane PKC activity was up-regulated after scald and showed a positive correlation with the change of TNF-alpha mRNA. Expression of IkappaB-alpha first decreased at 2 PBH and then increased to high level at 24 PBH. When 12 PBH was chosen as the time point for in vitro intervention with the application of specific NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC), PKC inhibitor H-7 and PNS, both TNF-alpha mRNA expression and NF-kappaB activity decreased significantly.


CONCLUSIONS
These results indicate that abnormal expression of TNF-alpha mRNA of macrophages might be regulated by PKC-NF-kappaB signaling following severe burn. PNS might play an anti-inflammatory effect by inhibiting NF-kappaB activity and TNF-alpha mRNA expression.
Wang
Yong
Y
Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
Peng
Daizhi
D
Huang
Wenhua
W
Zhou
Xin
X
Liu
Jin
J
Fang
Yongfei
Y
D000818:Animals; D015153:Blotting, Western; D002056:Burns / Q000378:metabolism*; D004586:Electrophoresis; D005260:Female; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D053723:Panax notoginseng; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012503:Saponins / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D016328:NF-kappa B; D012333:RNA, Messenger; D012503:Saponins; D014409:Tumor Necrosis Factor-alpha