The fate of Schwann cells isolated from axonal contact.
J Neurocytol 1978 Oct; 7(5):555-569
Distal tibial nerve stumps in 14 rats and 6 rabbits were prepared to study the behavior of Schwann cells in chronically denervated stumps and after transplantation from the stumps to the cornea. Following tibial nerve transection, all nerve fibers in the distal stump of the tibial nerve underwent degeneration involving dissolution of the axon and myelin sheath, degradation, and eventual removal from the nerve fascicle. A few regenerated myelinated and unmyelinated fibers were found after 15, 18, and 58 weeks. By 7 weeks, the nerve stump in rabbits was almost completely free of debris, but this took longer in rats. Transplantation of the Schwann cells to the cornea in rabbits resulted in cell death, and breakdown and dissolution of the transplant within 6 weeks. The authors conclude that loss of axonal contact causes Schwann cells to undergo division and alignment into columns, which progressively atrophy and may eventually disappear. Maintenance of Schwann cells in distal nerve stumps is dependent partly on axonal contact. The presence of myelin debris and lipid vacuoles, coupled with the scarcity of macrophages, indicate that Schwann cells play a major role in myelin degradation. These findings are pertinent to surgical management of peripheral nerve injuries in man, because loss of Schwann cells would hinder axonal growth and target tissue reinnervation.
NIOSH-Publication; NIOSH-Grant; Neurotoxic-effects; Laboratory-animals; Peripheral-nervous-system; Cellular-function; Neurolysis; Nerve-fibers; Neurophysiology; Membrane-dysfunction; Nuclear-membrane; Research-laboratories
Pathology Albert Einstein Coll of Med 1300 Morris Park Avenue Bronx, N Y 10461
Neurotoxic Disorders; Neurotoxic-effects
Journal of Neurocytology
Yeshiva University, New York, New York