The origin of reactive cells in retrograde and Wallerian degeneration. Experiments with intravenous injection of 3H-DFP-labeled macrophages.

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.