Differential modulation of TLR2 and TLR4-induced TNF production by murin haemorrhagic shock

Objective. - To investigate the influence of haemorrhagic shock in mice on ex vivo TNF production by whole blood cells (WBC) stimulated through Toll-like receptors (TLR) 4 and 2. Study design and animals. - Experimental study using BALB/c male mice. Methods. - Haemorrhage (0,026 +/- 0,003 ml/g) by transparietal cardiac puncture under general anaesthesia. Measurement of left intraventricular pressure through a direct subcostal cardiac puncture. Possible restitution of shed blood volume (SBV) in retroorbital venous plexus, 60 minutes following haemorrhage. Lethal exsanguination 120 minutes following general anaesthesia (Control group), cardiac puncture (Sham group), blood sample (Haemorrhage group), or 60 minutes following SBV retransfusion (SBV group). Cultures (24 hours) of whole blood from the exsanguination, alone or with Escherichia coli endotoxin (LPS, TLR 4) or with heat-killed Staphylococcus aureus Cowan (SAC, TLR 2). Assessment of TNF levels in the cultures supernatant (Elisa). Results. - Hemorrhage (similar to 30% of calculated blood volume) resulted in arterial hypotension (-50%) which was reversed by SBV retransfusion. TNF production by LPS-stimulated WBC was reduced by haemorrhage (similar to-50%) with or without SBV retransfusion. TNF production by SAC-stimulated WBC remained unchanged. Conclusion. - The reduction of proinflammatory cytokines production by WBC stimulated with pathogen-associated molecular patterns is not a generalized phenomenon following murin haemorrhagic shock. It depends on the used stimulus and studied signalling pathways. (c) 2005 Elsevier SAS. Tous droits reserves.