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(3)Study on role of Kupffer cells in the induction of tolerance after liver transplantationFigure 7　The survival rate after liver transplantation was 80% or more in groups 1, 2 and 3, but all died within 24 hours in groups 4 and 6 and all died within 28 days in group 5, no long term survival was obtained.Figure 8　Liver tissue ATP during hepatic cold preservation was significantly lower in the 72-hour fasting group.Next, we conducted a study on “Role of Kupffer cells in the induction of tolerance after liver trans-plantation”2）.The subjects used DA rats as donors and Lewis rats as recipients. This combination is a rejection model, in which acute rejection occurs within 12 days and all rats die. Group classification is as follows: control group; group in which only liver transplantation was performed, donor specific blood transfusion (DST) group; group which administered to recipient 1 ml of blood collected from donor 7 days before liver transplantation, and Gd+DST group; group in which gadorinium was administered to recipient 9 and 8 days before trans-plantation, and DST was performed 7 days before transplantation. In order to investigate the effect of gadorinium on phagocytes of Kupffer cells, the rats were euthanized. They received colloid carbon intravenously and died fifteen minutes later; liver tissue was observed by light and electron micros-copy. The measurement items were the survival rate and average survival time of recipient after liver transplantation, and hepatic histopathological findings 4 and 7 days after liver transplantation.Gadorinium is a type of metal salt that suppresses the activity of the reticuloendotherial system, including hepatic Kupffer cells. Electron micro-graphic examination clearly shows the presence of numerous carbon particles within the cytoplasmic vacuoles of Kupffer cells (Figure 9). In contrast, Kupffer cells in gadorinium-pretreated rat showed almost no carbon uptake (Figure 10).The mean survival time was significantly increased to 52.7 days in the DST group compared to 11.6 days in the control group. In Gd+DST group, the survival time was 27.7 days, which was signifi-cantly shorter than that in the DST group.The survival rate of recipients after liver trans-plantation was up to 70 days in the DST group, and Figure 9　Electron micrographic examination clearly shows the presence of numerous carbon particles within the cytoplasmic vacuoles of Kupffer cells.435