What Is Wallerian Degeneration?

Wallerian degeneration, also known as secondary degeneration, refers to the sequential changes in the nerve fibers that occur at the distal end of a nerve axon due to trauma. Due to the interruption of the axoplasm transport, the distal part of the axonal stump quickly degenerates and disintegrates from the proximal end to the distal end. These fragments are engulfed by neural membrane cells and macrophages. The same changes occurred in the axons and myelin sheaths near the stump, but usually only one or two Lang Fei knots to the proximal end did not progress. Nerve membrane cells proliferate, forming the nerve membrane tube of the Bungner zone in the basal layer, and the regenerating branch of the proximal axon at the stump extends to the distal end. If the axon breaks near the cell body, it will cause necrosis of the cell body. ^[1]
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Wallerian degeneration, also known as secondary degeneration, refers to the sequential changes in the nerve fibers that occur at the distal end of a nerve axon due to trauma. Due to the interruption of the axoplasm transport, the distal part of the axonal stump quickly degenerates and disintegrates from the proximal end to the distal end. These fragments are engulfed by neural membrane cells and macrophages. The same changes occurred in the axons and myelin sheaths near the stump, but usually only one or two Lang Fei knots to the proximal end did not progress. Nerve membrane cells proliferate, forming the nerve membrane tube of the Bungner zone in the basal layer, and the regenerating branch of the proximal axon at the stump extends to the distal end. If the axon breaks near the cell body, it will cause necrosis of the cell body. ^[1]

Chinese name

Wallerian degeneration

Foreign name

Wallerian degeneration

nickname

Secondary degeneration

The cell body of a nerve cell is its trophic center. If a protrusion leaves it, it will break down and eventually disappear. Therefore, when the axon (peripheral nerve) is severed by trauma, the rupture of nerve fibers first occurs at the stump. In 1850, Waller first made a classic description of this lesion, when he observed it on fresh, unfixed tissue. Waller observed that when the nerve was traumatically cut, the nerve fibers at the distal end of the cut had a phenomenon called "coagulation", and then broke to form neatly arranged broken particles. Later, scholars such as Cajal and Nageotte described the lesions seen under the light microscope. This condition is commonly seen in trauma and can affect the entire neural trunk or several nerve bundles. In addition to traumatic severance, any pathological process that affects the connection between the soma and nerve fibers can produce this change. Therefore, some scholars call similar lesions caused by non-mechanical injuries "Wailer / Wallerian-like degeneration." Such as cerebral cortex infarction, neuron degeneration and necrosis can cause Wallerian degeneration of the corresponding nerve fibers in the white matter. ^[2]