The pathogenesis of primary internodal demyelination produced by acetyl ethyl tetramethyl tetralin: evidence for preserved Schwann cell somal function.
Sterman AB; Spencer PS
J Neuropathol Exp Neurol 1981 Mar; 40(2):112-122
The pathogenesis of primary internodal demyelination induced by acetyl-ethyl-tetramethyl-tetralin (88299) (AETT) was studied in rats. Sprague-Dawley-rats were administered 0 or 50mg/kg AETT daily in their diet for up to 14 weeks. One or 2 days after treatment started the left sciatic nerve complex was traumatized by placing a perineurial window in the peroneal nerve, producing a distal nerve stump in the tibial nerve, or inflicting a focal seral nerve crush lesion. Selected animals were killed at 6, 10, and 14 weeks and the tibial nerves were isolated. Fibers teased from tibial nerve branches were subjected to morphometric analysis. Internodal lengths and numbers of Schmidt-Lanterman incisures (SLIs) were determined. At 6 weeks AETT significantly increased the number of SLIs per internode. The number of SLIs visible per internode increased proportionately with internode length. Juxtanodal and internodal myelin bubbles were seen by 10 weeks. By 14 weeks myelin stripping by intramyelinic phagocytes beginning in the paranodal regions and advancing toward the somal region of the Schwann cells was observed. Many large diameter fibers composed almost entirely of short remyelinated fibers were seen. The Schwann cells responded to the surgical injuries by developing myelinated and unmyelinated fibers. The Schwann cell response was not affected by AETT. The authors conclude that AETT damages myelin directly. SLIs undergo changes before demyelination. AETT induced demyelination is not associated with a major dysfunction of Schwann cells.
NIOSH-Publication; NIOSH-Grant; Neurotoxic-effects; In-vivo-studies; Laboratory-animals; Histopathology; Laboratory-techniques
Pathology Albert Einstein Coll of Med 1300 Morris Park Avenue Bronx, N Y 10461
Neurotoxic Disorders; Neurotoxic-effects
Journal of Neuropathology and Experimental Neurology
Yeshiva University, New York, New York