Assessment of histocompatibility of different hemoglobin solutions using mesenteric perfusion on the small bowel of the male Wistar rat.

Histocompatibility assessment of 70 g/l stroma-free hemoglobin solutions pyridoxylated or not, and purified or not, was carried out using vascular perfusion of the intestine of rats. Mechanical and ultrastructural changes in the organ and the arteriovenous difference of PO2 were compared to those obtained with albumin, gelatin and dextran. Overlapping epithelium conserves its structure in the presence of hemoglobin, whereas it is partially or totally destroyed with the plasma substitutes. Nevertheless, with non pyridoxylated hemoglobin there is a strong detachment of the epithelium from the lamina propria. The intestine, irrigated by the hemoglobin solutions shows efficient peristalsis, but this totally disappears with plasma substitutes. For similar arterial PO2, for all the solutions, the arteriovenous difference was of 100 mmHg for the hemoglobin solutions, whereas they never exceeded 60 mmHg for the plasma substitutes. Hemoglobin pyridoxylation led to an arteriovenous difference significantly superior (p less than 0.001) to those obtained using non modified hemoglobin. With their O2 supply hemoglobin solutions appear able to limit the development of hypoxia in the tissue. The continuation of peristalsis and the weak ultrastructural modifications confirm the slight histological improvement gained when using pyridoxylated hemoglobin. Nevertheless an extravasation appeared constantly, as well as flow reduction during perfusion with the hemoglobin solutions.