ANTIHISTAMINERGIC PRETREATMENT PREVENTS TISSUE EXTRAVASATION OF ALBUMIN FROM INTRAABDOMINAL 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 H-1 and H-2 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 nonpretreated (n=9). In the traumatized rats, given pyrilamine 10 mg kg(-1) (H-1) plus cimetidine 25 mg kg(-1) (H-2) 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 wail and the pancreas. In the nontraumatized 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.