New method for isolation of both kidneys for studies of vascular reactivity in rats

The isolated perfused rat kidney technique is one of the most widely used methods in renal research. It has proven useful to investigate biochemical, physiological, pharmacological and pathophysiological aspects of renal function, allowing variables to be changed in a controlled manner and eliminating systemic influences. This study was designed to test a new surgical procedure to isolate both kidneys for their utilization in this technique, mainly as a vascular preparation. The viability of the resulting preparations was compared with those obtained by the classical method, analyzing the responsiveness to the vasoconstrictor phenylephrine and to the endothelium-dependent vasodilator acetylcholine. Vascular reactivity was evaluated under normal conditions and in endothelium-denuded preparations. The dose response curves to phenylephrine and to acetylcholine were similar in the three experimental groups, regardless of the procedure used for kidney isolation, in both endothelium-intact and endothelium-denuded preparations. We give a step-by-step description of the isolation method and key points for the success of the technique. In conclusion, the surgical procedure proposed in this paper reduces the number of animals required by half and hence reduces the cost of the experiments. This novel procedure is of special interest for acute experiments to test new vasoactive drugs and for analysis of the action mechanisms of these drugs. It could also be used in chronic studies or in genetically modified animals when different experimental protocols are performed on the left and right kidneys and to improve the accuracy of the results by analyzing cases in duplicate.