Contribution of the sympathetic nervous system on the burn-associated impairment of CCL3 production

Previously, we have reported that the susceptibility of burned patients to infectious complications is increased when the production of CC-chemokine ligand 3 (CCL3) is impaired. In this study, the role of the sympathetic nervous system on impaired CCL3 production and antibacterial resistance following burn injuries was investigated. Normal mice were resistant (65% survival) to cecal ligation and puncture (CLP)-induced sepsis, while the same CLP killed 90% of thermally injured mice (TI-mice). However, TI-mice resisted CLP-induced sepsis (60% survival) when they were previously treated with CCL3 or sympathectomized with 6-hydroxydopamine (6-OHDA). Augmentation of host resistance against CLP-induced sepsis by 6-OHDA was abrogated by anti-CCL3 mAb treatment. Norepinephrine (NE) production was increased in circulation of TI-mice, and treatment of TI-mice with 6-OHDA resulted in the inhibition of NE secretion. CCL3 production was impaired in cultures of T cells from TI-mice or normal T cells treated with NE, even when stimulated with anti-CD3 mAb. However, CCL3 was produced by mAb-stimulated T cells from TI-mice previously treated with 6-OHDA. These results indicated that by inhibiting CCL3 production the sympathetic nervous system contributes to the increased susceptibility of TI-mice to sepsis.