Antihistaminergic pretreatment prevents tissue extravasation of albumin from intra-abdominal trauma in rats.

Intra-abdominal surgery causes a loss of plasma into tissues within and around the abdomen, endangering tissue viability. Mast cells, containing histamine, are abundant in the abdominal cavity. In a model of mechanical intra-abdominal trauma, we investigated whether pretreatment with histaminergic H1 and H2 receptor blockers counteracts this extravasation. In Wistar rats under chloralose anaesthesia, tissue clearances of labelled albumin were determined by a double isotope technique. Four groups were studied: Traumatized rats, pretreated (n = 10) and non-pretreated (n = 9): non-traumatized rats; pretreated (n = 10) and non-pretreated (n = 9). In the traumatized rats, given pyrilamine 10 mg kg-1 (H1) plus cimetidine 25 mg kg-1 (H2) just before the trauma, the blockers prevented the haemoconcentration from loss of plasma and the drop in arterial pressure during the very trauma procedure, observed among non-pretreated rats. Furthermore, they significantly decreased the clearance of albumin in the abdominal wall and the pancreas. In the non-traumatized animals, the blockers lowered arterial pressure and heart rate. In conclusion, the anti-histaminergic pretreatment decreased the trauma induced leakage of albumin, by mechanisms which may involve readjustments of pressures and flows in capillaries as well as a prevention of histamine effects on capillary permeability.