The origin of reactive cells in retrograde and wallerian degeneration

Summary In order to examine the possible haematogenous origin of phagocytes in anterograde and retrograde degeneration, rabbit peritoneal macrophages were labeled in vitro with ³H-DFP and injected intravenously into host animals. Four or five days prior to the injection, the facial nerve was avulsed and the sciatic nerve ligated in five recipients. The animals were killed 24 h after the injection of the macrophages. Labeled cells were found in that part of the sciatic nerve which was mechanically damaged and in the liver and spleen but not in areas with retrograde or Wallerian degeneration. The possible interpretation of these findings is discussed.The present experiments were performed by M.O. after suggestions by A.T. These studies were supported by a grant from the Deutsche Forschungsgemeinschaft