CAPSAICIN PRETREATMENT OF RATS DOES NOT PREVENT TISSUE EXTRAVASATION OF ALBUMIN FROM INTRAABDOMINAL TRAUMA

Intra-abdominal surgery causes a loss of plasma into tissues within and around the abdomen, predisposing to a decreased tissue viability and postoperative complications. In a rat model of intra-abdominal trauma, we investigated whether neuropeptides released from thin afferent nerve endings may contribute to this extravasation. Newborn male Wistar rats were pretreated with capsaicin 50 mg/kg s.c., leading to a lifelong degeneration of thin afferents. The same animals, when adult, were subjected to experiments under chloralose anesthesia in which tissue clearances of radiolabelled albumin were determined by a double isotope technique. Non-pretreated animals served as controls. In non-traumatized animals, pretreated rats had a higher loss of labelled albumin in calf muscle. In animals subjected to the standardized intra-abdominal trauma, the pretreatment did not decrease the trauma-induced loss of albumin. In neck skin, the loss of protein was higher in pretreated animals, possibly due to a decreased trauma-induced sympathetic activation. In conclusion, degeneration of thin afferent fibers may alter the autonomic reflex response to intra-abdominal trauma, but neuropeptide release from afferents apparently plays no role in the relocation of albumin.