Effects of preservation of rat lungs in a hypothermic medium on alveolar morphology

The increasing use of organs such as liver, lung, heart, pancreas, kidney a nd small intestine for transplantation purposes necessitates the developmen t of optimum preservation techniques. The aim of our study was to investiga te time-related morphological changes in alveoli during preservation of rat lungs in hypothermic Euro-Collins solution. Lungs were perfused via the pu lmonary arteries with Euro-Collins solution at a temp of 19 degrees C. Tota lly perfused lungs were placed in Euro-Collins solution and stored for 6, 1 2 and 24 h at 4 degrees C. Biopsies were taken and prepared for examination at the light and electron microscopical level. Light microscopic examinati on revealed good preservation of the alveoli after storage for 6 h and mode rate damage of alveolar architecture after 12 h of preservation. Severe deg eneration of alveoli was found after 24 h of storage. The main ultrastructu ral changes were observed in lungs stored for 12 h and 24 h. After 6 h of s torage, tissue damage was not found. Pneumocytes type II lost their apical microvilli and lamellar bodies were electron-lucent, indicating lamellar de generation after 12 and 24 h of storage. Pneumocytes type I were also damag ed. Their cytoplasm contained many vacuoles. Endothelial lining of the capi llaries was contracted. Endothelial cells also showed many vacuoles. Edema around the capillaries was observed. We conclude on the basis of our morpho logical study, that Euro-Collins solution at low temperature is a good pres ervative for a short period of time only, but serious tissue damage occurs after periods of preservation longer than 12 h.