Influence of different transplantation methods on liver cell survival in spleens of rats

Isolated hepatocytes, liver tissue suspensions, or liver tissue cylinders from biopsies were transplanted into the spleens of adult male rats. Donors were syngenic fetuses, syngenic or allogenic adult rats, or autologous material was obtained from the rat's own liver. The outcome of the different transplantation procedures was evaluated at 1 and 6 months after surgery. Additionally the influence of a 30% hepatectomy (HX) on the result of the transplantation was investigated. When fetal material was transplanted, the best results in sequence with respect to the number of viable hepatocytes within the spleens were obtained (1) after transplantation of syngenic fetal liver tissue suspensions, (2) syngenic fetal liver tissue cylinders and (3) syngenic fetal isolated hepatocytes. HX only improved the results with transplantation of syngenic fetal isolated hepatocytes. After transplantation of syngenic fetal liver tissue suspensions and isolated hepatocytes, but not after transplantation of syngenic fetal liver tissue cylinders, the number of hepatocytes was higher at 6 months than at 1 month after surgery. Concerning syngenic adult liver material, only transplantation of isolated hepatocytes lead to a remarkable and increasing number of surviving hepatocytes at both 1 and 6 months after surgery. These results were further improved by HX. With syngenic adult liver, the other transplantation methods yielded no or nearly no viable hepatocytes in the spleens. In comparison to the results after transplantation of syngenic fetal liver tissue suspensions, transplantation of syngenic adult isolated hepatocytes was less efficient, but still yielded more viable hepatocytes than the transplantation of syngenic fetal isolated hepatocytes. After transplantation of autologous liver tissue suspensions, autologous liver tissue cylinders or allogenic adult liver material only few surviving hepatocytes were observed. At 1 month after transplantation of syngenic fetal liver material, syngenic adult isolated hepatocytes or autologous liver tissue cylinders into the spleens 40-80% of the explants consisted of bile ducts independent from the transplantation method. At 6 months after surgery the bile ducts were much less and in some cases no longer visible. After transplantation of autologous liver tissue suspensions or allogenic adult liver material only very few bile ducts were seen, but anyhow in those cases only poor results were obtained. Thus, with respect to transplantation outcome and long-term liver cell survival, intrasplenic transplantation of both syngenic fetal liver tissue suspensions and syngenic adult isolated hepatocytes seem to be the most suitable methods and should be chosen for further investigations on explant morphology and function.