We developed a model for screening drugs to reduce ischemic liver damage using Hep G2, a hepatoblastoma cell line, and examined the effect of OP 2507, a stable analogue of prostacyclin, on hypoxic cell damage. Hypoxic exposure of the cells was done for 16 hr in an air-tight chamber which was placed inside an incubator and was purged with 5% CO2/95% N2. Adding OP 2507 (0.01-10 ng/ml) to the incubation medium during hypoxic exposure reduced mitochondrial damage estimated by MTT-reducing activity, while it failed to inhibit lactate accumulation in the medium. OP 2507 seems to be a good candidate for improving the preservation of liver allografts.