Measurement of D-xylose gut absorptive capacity in conscious rats

Recently, it has become evident that the gut plays a central role in the development of multiple organ failure in the critically ill patient after trauma-hemorrhage and sepsis. However, it remains unknown whether gut absorptive capacity (GAC) is altered under those conditions. The aim of this study, therefore, was to use a rat model for GAC measurements independent of the function of other organs and to determine whether GAC is altered after trauma. Rats (n = 79; 250-325 g) were lightly anesthetized with ether, and a 6-cm midline laparotomy was performed (i.e., trauma induced). A nasogastric tube was inserted and after cannulation of various blood vessels, the animals were allowed to recover from anesthesia. They were then divided into various groups for determinations of GAC over a period of 5 days. Control animals had GAC measurements without any surgery being performed on them. GAC was determined using the 1-h D-xylose absorption test and measuring D-xylose concentration in the portal blood. Results demonstrate that GAC 1) is significantly depressed for the first 48 h after trauma, 2) returns to normal 72 h after trauma, and 3) is further depressed by hemorrhage and resuscitation and by sepsis after trauma. Thus the model described here can be used to investigate the effects of trauma, trauma plus hemorrhage, trauma plus sepsis, hemorrhage alone, and sepsis alone on GAC, independent of the function of other organs.