Influence of resuscitation volume on blood cells TNF production in a murine model of haemorrhage.

The influence of haemorrhage and resuscitation on Tumour Necrosis Factor (TNF) production by whole blood cultures under endotoxin (Escherichia coli LPS) stimulation was investigated in male BALB/c mice. Haemorrhagic shock was induced by removing 0.026 +/- 0.003 mL of blood/g via a cardiac puncture, resulting in a 50% decrease in arterial pressure and a metabolic adidosis. Animals were resuscitated successfully (normotensive) despite a residual base deficit and hyperlactatemia, 60 min after the haemorrhage by the restitution of shed blood volume (SBV) with or without an additional volume of crystalloid (Lactated Ringer's solution) equal to 50, 100 (isovolumetric resuscitation) or 200% of SBV. Pulmonary failure (hypoxia-hypercarbia) and myocardial injury (troponin I release) was observed in this last group. TNF production by whole blood cultures stimulated ex vivo by LPS was estimated 60 min after the end of resuscitation. Haemorrhage resulted in a 48-60% decrease in TNF production. This decrease so-called 'leukocyte deactivation' was not modified by the restitution of SBV with or without crystalloid except for isovolumetric resuscitation which resulted in the cytokine level returning to control in the absence of clear cardiopulmonary dysfunction. In the present murine model of haemorrhage, modifying resuscitation volume influences in vitro TNF production in whole blood cultures challenged by LPS.