Dobutamine maintains intestinal villus blood flow during normotensive endotoxemia: an intravital microscopic study in the rat.

PURPOSE: The gut plays a pivotal role in sepsis. Intestinal hypoperfusion with subsequent ischemia leads to translocation of endotoxin. Dobutamine has been demonstrated to increase mesenteric blood flow during endotoxic shock; however, its effects on mucosal blood flow especially in intestinal villi is not known. Therefore, we investigated its influence on the blood flow and the arteriolar diameters in intestinal villi in a model of normotensive endotoxemia.

MATERIALS AND

METHODS

Twenty-one male Wistar rats were divided into three groups: (1) control, saline; (2) endotoxin, endotoxin 1.5 mg/kg during 60 minutes; and (3) dobutamine, endotoxin 1.5 mg/kg (60 minutes) and dobutamine 2.5 micrograms/kg/min during 120 minutes. Villus blood flow and arteriolar diameters were determined at 0 minutes, 60 minutes, and 120 minutes in each group using intravital microscopy.

RESULTS

Villus blood flow was constant in the control group, significantly reduced at 120 minutes in the endotoxin group (120 minutes, 55.1 +/- 7.4%), and remained at baseline values in the dobutamine group. The arteriolar diameters remained constant in the control and the dobutamine groups, but they were significantly reduced in the endotoxin group at 120 minutes (7.8 +/- 0.2 to 6.5 +/- 0.7 micron).

CONCLUSION

Our results indicate that in rats with normotensive endotoxemia, arteriolar diameters and blood flow in intestinal villi were reduced. Dobutamine prevented arteriolar constriction and maintained villus blood flow at preendotoxemic values.