Schwann cell multiplication in Trembler mice

Peripheral nerves of the mutant mouse Trembler are characterized by a severe myelin deficit and an increased number of Schwann cells. On the basis of radioautographic and quantitative morphologic investigations, the present study documents: i an abnormal persistence of post-natal Schwann cell proliferation in Trembler mouse nerves which, in unaffected animals, are composed of myelinated fibres; ii normal morphology, numbers and proliferation of Schwann cells in the unmyelinated (Remak) fibres of Trembler mice; and iii replication of the increased rate of Schwann cell multiplication as well as the myelin deficit, when segments of Trembler sciatic nerves are transplanted into the sciatic nerves of normal mice. Thus, the continued proliferation of Trembler Schwann cells must be related to the primary inability of these cells to produce and maintain a normal myelin sheath; axonal or general systemic abnormalities do not appear to play a major role in the pathogenesis of these disorders in the Trembler mouse.