BACKGROUND:A suitable perfusate is very important in reducing various problems in liver preservation,prolonging the time of organ preservation and enhancing the quality of donor tissue.University of Wisconsin(UW)solution is the most successful solution for preserving multiple organs at present,but it has many shortcomings.We set out to develop a new liver preservation solution(KYL solution) and study its effects on apoptosis in rat liver undergoing cold preservation. METHODS:Using non-circulated isolated perfused rat liver(IPRL),we randomly preserved Sprague-Dawley rat livers for 0,4,8,16,24,and 48 hours with KYL solution or UW solution.The effects were assessed by measuring the content of free radicals in Krebs-Henseleit solution and the intracellular calcium content of hepatocytes,assessing hepatocellular apoptosis and related-gene expression,and observing the morphological changes in liver.To evaluate the protection by KYL and UW solutions in rat liver perfusion and preservation,we chosed normal saline for negative comparison. RESULTS:The intracellular calcium content of the liver preserved in KYL solution was less than that preserved in UW solution.At every different period of preservation, the malonaldehyde and superoxide dismutase content in Krebs-Henseleit solution,the percentage of apoptotic cells and the expression patterns of apoptosis-related-genes were similar in livers preserved in KYL and UW solutions. Morphological changes in the two groups were almost the same.The variables in both groups were better than those of livers preserved in normal saline.Both KYL and UW solutions protected rat liver from ischemia-reperfusion injury. CONCLUSIONS:KYL solution is superior to UW solution in preventing calcium overload.More severe hepatocyte damage may appear in the KYL group than in the UW group and the effect of KYL solution on apoptosis in rat liver preservation is similar to that of UW solution. BACKGROUND: A suitable perfusate is very important in reducing various problems in liver preservation, prolonging the time of organ preservation and enhancing the quality of donor tissue. University of Wisconsin (UW) solution is the most successful solution for preserving multiple organs at present, but It has many shortcomings. We set out to develop a new liver preservation solution (KYL solution) and study its effects on apoptosis in rat liver undergoing cold preservation. METHODS: Using non-circulated isolated perfused rat liver (IPRL), we randomly preserved Sprague -Dawley rat livers for 0, 4, 8, 16, 24, and 48 hours with KYL solution or UW solution. The effects were assessed by measuring the content of free radicals in Krebs-Henseleit solution and the intracellular calcium content of hepatocytes, assessing hepatocellular apoptosis and related-gene expression, and observing the morphological changes in liver. evaluation of the protection by KYL and UW solutions in rat liver perfusion and preservation, we RESULTS: The intracellular calcium content of the liver preserved in KYL solution was less than that preserved in UW solution. At every other period of preservation, the malonaldehyde and superoxide dismutase content in Krebs-Henseleit solution, the percentage of apoptotic cells and the expression patterns of apoptosis-related-genes were similar in livers preserved in KYL and UW solutions. Morphological changes in the two groups were almost the same. the variables in both groups were better than those of livers preserved in normal saline .Both KYL and UW solutions protected rat liver from ischemia-reperfusion injury. CONCLUSIONS: KYL solution is superior to UW solution in preventing calcium overload. More severe hepatocyte damage may appear in the KYL group than in the UW group and the effect of KYL solution on apoptosis in rat liver preservation is similar to that of UW solution.