Lymphatic obstruction and lymph node changes--a study of the rabbit popliteal node

Dense cortical lymph node fibrosis is associated with primary lymphedema and proximal obstructive hypoplasia. The fibrosis is not related to the duration of disease nor to episodes of clinical cellulitis. This suggests that the disease may start in the nodes but the effects of obstruction in the adjacent lymph vessel must be elucidated before the assumption is made. The popliteal nodes of 49 rabbits were studied following the ligation of either afferent or efferent lymphatics, and compared with nodes following a sham operation. The efficacy and late effects of ligation were assessed in half the rabbits by cinelymphangiography. In the rest Patent Blue Violet and not Lipoodol was used to minimize any spurious effect on node histology. The rabbits were sacrificed between 6-84 days. Node area was measured on serial x-rays and node volume after removal of the node. Afferent ligation resulted in a significant and permanent decrease in size (p less than 0.005) and lymphocytic congestion; efferent ligation resulted in an increase in size (p less than 0.02) and large lymph spaces. The dense node fibrosis of primary lymphedema was not seen.