VASCULAR RESISTANCE AND EDEMA IN ISOLATED RABBIT KIDNEY PERFUSED WITH A CELL-FREE SOLUTION

The object of these experiments was to develop a method for the uniform perfusion of isolated rabbit kidneys at +37°C with cell-free fluids, without edema and with normal vascular resistance. We have found that dextran preparations of mean molecular weight 70,000 or 115,000 are not completely retained within the capillaries of the isolated rabbit kidney and their use as the sole colloid in a cell-free perfusion system at +37°C leads to progressive edema throughout the perfusion. If low flows are employed to minimize edema, perfusion is incomplete with many medullary vessels remaining full of blood. Filtration of the perfusion solution, the prevention of vascular spasm with papaverine, and the inclusion of 6%, w/v, dextran permit perfusion for short periods at normal vascular resistance, but there is strong evidence that the integrity of the vascular endothelium is impaired, leading to a progressive rise in resistance and an increase of edema. Improved results will require the development of a perfusion fluid which permits the capillary membrane to retain its normal permeability characteristics, and which prevents a rise in vascular resistance. It is possible that these two basic requirements are linked, and that the solution of one problem will eliminate the other. © 1969.