The response of the dog colon mucosa one hour's ischaemia.

Segments of dog colon were subjected to one hour's ischaemia, and their morphology and function were studied either immediately after the ischaemia or 24 hours later. As functional tests, net sodium transport across the mucosa in vitro, the transport capacity in vitro for sugars and amino-acids, tissue respiration, lactate production, and the liberation of acid phosphatase were applied. Immediately after the ischaemia, all parameters differed significantly from the control mucosa: net sodium transport was abolished; amino-acid and sugar uptake, oxygen consumption and lactate production were reduced; and lysosomal enzyme release was increased. All parameters, except sugar uptake, had normalised 24 hours after the trauma. Histological examinations revealed much variation in the lesions occurring after the ischaemia, varying from slight epithelial desquamation to considerable mucosal destruction. In most cases, the mucosa had almost normalised 24 hours later. Morphometric analysis revealed decreased mean mucosal thickness immediately after the trauma, though 24 hours later, there was again no significant difference with the control group.