OBJECTIVETo investigate the effect of NF-kappaB activation on the early expression of proinflammatory cytokines in myocardium and early myocardial dysfunction in burn rats.

METHODSOne hundred and seventy Wistar rats were enrolled in the study and randomly divided into three groups, i. e. control( C, n = 20, with isotonic saline solution) , burn ( B, n = 90, with isotonic solution after burns) and pyrrolidine dithiocarbamate (PDTC, n =60, with isotonic saline and 250 mg/kg PDTC after burns) groups. The rats in B and PDTC groups were inflicted with 35% TBSA full-thickness burns on the back. The activity of myocardial NF-kappaB was determined by electrophoretic mobility shift assay at 1 , 3, 6, 12,24 postburn hours (PBH), with expression of integral absorbance ( A ) value . The expression of myocardial tumor necrosis factor alpha ( TNF-alpha) mRNA was assessed by reverse transcription polymerase chain reaction( RT-PCR) and in situ hybridization at 6, 12 PBH, with expression ofA value. The left ventricular systolic pressure( LVSP) , the left ventricular end diastolic pressure (LVEDP) ,the maximum rate of rise of left ventricular pressure ( +/- dp/dt max) were also observed at 3, 6, 12,24 PBH. RESULTS The activity of myocardial NF-KB in B group was markedly increased at 1 PBH [ (20. 3+/-3. 4) x 104A ] ,which was obviously higher than that in C group (2. 2 +/- 0. 4) x 104A , P <0.01]. It peaked at 3 PBH, and was still evidently higher than that in C group at 24 PBH ( P <0. 01). The expression of TNF-alpha mRNA was obviously higher than that in C group at 3 PBH ( P < 0. 01) , peaking at 6 PBH, and it was mainly expressed in myocardium. The expression of LVSP and +/- dp/dt max were lower, but LVEDP was higher than that in C group during 3 -24 PBH ( P <0.01).