Effects of anesthesia on renal function and metabolism in rats assessed by hyperpolarized MRI.

PURPOSE: Anesthesia is necessary for most animal studies requiring invasive procedures. It is well documented that various types of anesthesia modulate a wide variety of important metabolic and functional processes in the body, and as such, represent a potential limitation in the study design. In the present study, we aimed to investigate the renal functional and metabolic consequences of 3 typical rodent anesthetics used in preclinical MRI: sevoflurane, inaction, and a mixture of fentanyl, fluanisone, and midazolam (FFM).

METHODS: The renal effects of 3 different classes of anesthetics (inactin, servoflurane, and FFM) were investigated using functional and metabolic MRI. The renal glucose metabolism and hemodynamics was characterized with hyperpolarized [1-13 C]pyruvate MRI and by DCE imaging.

RESULTS: Rats receiving sevoflurane or FFM had blood glucose levels that were 1.3-fold to 1.4-fold higher than rats receiving inactin. A 2.9-fold and 4.8-fold increased 13 C-lactate/13 C-pyruvate ratio was found in the FFM mixture anesthetized group compared with the sevoflurane and the inactin anesthetized groups. The FFM anesthesia resulted in a 50% lower renal plasma flow compared with the sevoflurane and the inactin anesthetized groups.

CONCLUSION: This study demonstrates different renal metabolic and hemodynamic changes under 3 different anesthetics, using hyperpolarized MR in rats. Inactin and sevoflurane were found to affect the renal hemodynamic and metabolic status to a lesser degree than FFM. Sevoflurane anesthesia is particularly easy to induce and maintain during the whole anesthesia procedure, and as such, represents a good alternative to inaction, although it alters the blood glucose level.