Dynamics of neutrophilic NF-kB translocation in relation to IL-8 mRNA expression after major trauma

Abstract.

Objective:

Systemic inflammation subsequent to polytrauma is connected to neutrophil (PMN) dysregulation characterized by reduced NF-kB-translocation and cytokine expression. The dynamics of NF-kB-activation as well as its down-stream regulation of IL-8-expression in PMN following major trauma remain unclear. The aim of this pilot study was to analyse NF-kB nuclear translocation in relation to IL- 8-mRNA-expression in PMN after major trauma.

Patients and methods:

PMN were isolated from blood samples of 15 major trauma patients (New Injury Severity Score, NISS > 16) drawn within 90 min and subsequently 6, 12, 24, 48, 72 h after trauma. NF-kB-translocation was analysed by Electrophoretic Mobility Shift Assay, EMSA and quantified by densitometry [arbitrary units], IL-8-mRNA-expression by RT-PCR, [copies/50 ng RNA]. Additionally, NF-kB-translocation and IL-8-expression in PMN of healthy volunteers were analysed natively (-control) and after LPS stimulation (+control).

Results:

NF-kB-translocation and IL-8-mRNA-expression was significantly increased in polytrauma patients (n=15; NISS: 34 ± 8 [mean ± SEM]) initially. In non-survivors, NFkB- translocation was significantly increased on admission and subsequently reduced within 6 h, while it increased in the survivors group. After 24 h, a second significant increase in NF-kB-activity and IL-8-expression was found in survivors that was subsequently reduced in both groups.

Conclusion:

This pilot study has shown that a concomitant initial increase in transcriptional NF-kB-activity and IL-8 mRNA expression was observed in the early posttraumatic period which preceded the down-regulation of the innate immune system.