OBJECTIVETo investigate the effects of burn serum on nuclear translocation of monocytic NF-kappaB heterodimers p50/p65 and the degradation of inhibiting kappaB (IkappaBalpha), so as to further explore the role of burn serum on the activation of monocytes.

METHODSPeripheral blood monocytes (PBMCs) isolated from healthy volunteers were employed as the target cells. The cells were stimulated by the serum from healthy volunteers and burn patients, and by burn serum together with pyrrolidine dithiocarbamate (PDTC). Sera from normal healthy volunteers were taken as control. The nuclear translocation of monocytic p50 and p65 at 30th, 60th, 120th and 480th post stimulation minutes (PSM) was observed with laser confocal microscopy. The degradation of monocytic IkappaBalpha protein at 30th, 60th, 90th and 120th PSM was determined by Western blot.

RESULTSCompared to that in control group, the nuclear translocation of monocytic p50 and p65 took place 30 min after the PBMCs were stimulated by burn serum, peaking at 30 to 60 min, but it gradually recovered to pre-stimulation state at 2 hrs with decreased intra-nuclear collection. Meanwhile, the IkappaBalpha degradation occurred within 30 min after PBMCs being stimulated by burn serum, and it peaked at 60 mins. However, IkappaBalpha gradually reappeared in the cytoplasm after 2 hrs of stimulation. PDTC (an antioxidants) could effectively inhibit monocytic IkappaBalpha degradation and nuclear translocation of NF-kappaB induced by burn serum.

CONCLUSIONBurn serum could induce nuclear translocation of p50 and p65 components of NF-kappaB in monocytes into the nucleus and degradation of IkappaBalpha, leading ultimately to the secretion of cytokines from the PBMCs.