Cold- and cryopreservation of dog liver and kidney slices.

The use of tissue slices in culture could decrease the number of animals used in health-related research and decrease experimental variation. This reduction may come about particularly if the methods of cold- and cryopreserving tissue slices are perfected, and one can conduct sequential in vitro experiments into xenobiotic metabolism, organ-specific toxicity, or organ-specific biochemical processes with tissue slices. With this goal in mind, dog liver and kidney slices were placed in cold storage at 0 degrees C using Viaspan (UW), Euro-Collins (EC), Sacks + prostacyclin (SP), and V-7 (V7) cold-preservation solutions for 10 days. Viability was assessed each day by measuring K+ content and protein synthesis after 4 h of incubation in Waymouth + 10% fetal calf serum (FCS). Dog liver slices can be cold-preserved in V7 for up to 7 days using K+ retention as the viability criterion but only up to 4 days using protein synthesis. Dog kidney slices can be cold-preserved in UW, EC, and V7 for up to 10 days using K+ retention, but only V7 could maintain protein synthesis for 10 days. Cryopreserved dog liver and kidney slices retained 63-68% of control viability after 4 h of incubation in FCS. The cryopreservation regimen included using 10% dimethyl sulfoxide in FCS as the cryoprotectant, a freezing rate of 0.5 degrees C/min for liver slices and 12 degrees C/min for kidney slices, and thawing in 37 degrees C FCS. Continued development of cold- and cryopreserving tissue slices could reduce the numbers of animals used and provide accurate and reproducible data.

The use of human lung slices in toxicology.

1. Successful use of agar-filled precision-cut rat lung slices in dynamic organ culture prompted the use of this technology with human lung. 2. The larger tissue mass of a human lung required that the trachea be cannulated with a balloon catheter and subsequently inflated with 4 liters of warm agar/medium mixture and then cooled before being precision-cut into 500 microns thick slices. 3. To characterize the human lung slices, viability and the effects of acrolein and nitrofurantoin were assessed over a period of 24 h using protein synthesis and nonprotein sulfhydryl content. 4. Control human lung slices synthesized protein at a linear rate and maintained a stable nonprotein sulfhydryl content for 24 h. 5. Slices incubated with acrolein exhibited no significant decrease in protein synthesis or nonprotein sulfhydryl levels until 24 h. 6. Incubation with nitrofurantoin exhibited a definite time- and dose-dependent inhibition of protein synthesis, and depletion of the cellular thiol pool. 7. These results indicate that this human lung tissue slice system may be used as an in vitro model to identify and screen pneumotoxicants.