Antiinflammatory properties of IL-10 rescue small-for-size liver grafts

The present study aims to investigate the potential therapeutic role of interleukin-10 (IL-10) in small-for-size liver transplantation. A syngenic rat orthotopic liver transplantation model was performed using either whole or 40% liver volume of Lewis rats as grafts according to the experimental design. IL-10 was given to the 40% grafts right after reperfusion, and also at 24 and 48 hours after transplantation. When no treatment was given, less than 40% of the small-for-size grafts survived indefinitely, whereas IL-10 treatment could increase the long-term survival rate of the small-for-size grafts to 80%. The 40% grafts presented with extensive areas of necrosis and increased number of apoptotic cells at the early phases after reperfusion. In addition, upregulation of plasma protein carbonyl content (PCC) levels was also detected in the 40% graft group. IL-10 treatment suppressed the upregulation of allograft inflammatory factor-1 (AIF-1) on macrophages in the 40% grafts, and at the same time, decreased the levels of plasma PCC, and improved the histology and function of the 40% grafts. The expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-alpha, and caspase 9 in the 40% grafts were upregulated after reperfusion, whereas the augmentation could be suppressed by the administration of IL-10. Finally, IL-10 culture could block AIF-1-mediated NO production and downregulate the expression of iNOS and TNF-alpha in a macrophage cell line. In conclusion, IL-10 rescued the small-for-size liver grafts by its antiinflammatory properties, through inhibition of AIF-1 mediated proinflammatory and proapoptotic activities of the macrophages during the early period after ischemia/reperfusion.