Ultrastructure of kidney preservation: varying the amount of an effective osmotic agent in isotonic and hypertonic preservation solutions.

Currently the level of effective (i.e., impermeant) osmotic agent necessary to prevent cell swelling during the cold storage of kidneys is not known. In the present investigation, we used light microscopy and transmission electron microscopy to evaluate the amount of the osmotic agent sucrose which is needed to protect the rat kidney parenchyma from damage over 24 and 48 hr of cold storage. Our observations indicate that when sucrose contributes 140 mOsmol or more to the total osmolality of phosphate-buffered solutions, most cell swelling and associated ultrastructural damage can be prevented over 48 hr of cold storage. We also found little difference between the quality of kidney ultrastructural preservation which results when kidneys are stored in isotonic (300 mOsmol) versus hypertonic (400 mOsmol) solutions that contain the same amount of sucrose. The overall quality of preservation seen with solutions which contain 140 or 200 mOsmol of sucrose is dramatically better than that which we previously observed with such clinically popular kidney preservation solutions as Collins, Euro-Collins, and Sacks.